Institutt for geologi og bergteknikk Hovedoppgaver 2008

2008

Amadou, Ibrahim (S. Lippard)

1D Basin Modelling and Hydrocarbon ResourceAssessment of the Taoudeni Basin, Mali. The intracratonic Taoudeni Basin is the largest sedimentary basin in NW Africa covering large parts of Mali and neighbouring Mauritania. The basin was formed during the mid-late Proterozoic and subsidence continued through to the mid-Paleozoic when Hercynian deformation and uplift occurred. Up to 6000 m of late Precambrian and Paleozoic sediments are found in the basin. A preliminary phase of drilling in the 1970s and 1980s penetrated most of the sedimentary succession and two potential petroleum systems, Late Precambrian and Paleozoic, have been defined. The Late Precambrian system has proven source rocks (algal stromatolites) and black shales and reservoirs in carbonates and sandstone sequences. The Paleozoic system comprises Silurian-Devonian marine shale source rocks and reservoirs in overlying Devono-Carboniferous sandstones and underlying Cambro-Ordovician sandstones. Potential trapping styles are unconformity traps and large scale Hercynian folds. There are several risks to exploration in the Taoudeni Basin. There is a lack of knowledge on the volume and distribution of source, reservoir and seal rocks in the basin, and the detailed structural architecture of the basin itself is poorly understood. Poblems with petroleum generation modelling in the basin include the thermal effects of Hercynian uplift and erosion and the intrusion of Mesozoic dolerites. Using a uniform low heat flow, appropriate for intracratonic basins, the provisional results indicated that the Paleozoic source rocks may have been only marginally mature prior to Hercynian uplift, whereas the Late Precambrian source rocks were probably mature to overmature prior to uplift. The resource assessment and hydrocarbon potential of the Infracambrian petroleum system has been carried out focusing on the source and reservoir rocks development in relation to hydrocarbon generation, migration and entrapment. The conditions that favour the discovery of a potentially commercial volume of hydrocarbons in the basin are: i. The distribution of the source and reservoir rocks within the basin. ii. The time relation between entrapment and maturation, heat flow and migration of the hydrocarbons. The basin‟s hydrocarbon resources are estimated using the “GeoX/Starter” software. Because of the limited data base on the Mali side, the data from Mauritania have been used to some extent to generate data base for the prospect evaluation. The recoverable oil resources in a single prospect are estimated to be 565.9 MMBL.

Árnason, Stefán Geir (B. Nilsen)

Prognose for tettingsinjeksjon i Rogfast undersjøiske tunnel. Prognosis for rock grouting in the planned Rogfast subsea tunnel. E39 Rogfast is an approximately 25 km long subsea road tunnel which is being planned by Statens vegvesen (Norwegian Public Roads Administration). The tunnel will cross the Boknafjorden and Kvitsøyfjorden between Randaberg and Vestre Bokn in the south-western part of Norway. The deepest point of the tunnel will be at around 360 m below sea level, so when completed, the Rogfast tunnel will be the longest and deepest subsea road tunnel in the world. A prognosis for rock grouting in the Rogfast subsea tunnel has been prepared based on knowledge about engineering geological conditions along the trace of the tunnel and experience from other tunnels in similar rock types in the Boknafjorden area. The grouting requirement is evaluated in the form of relative lengths of the tunnel which are assumed to require grouting for control of water leakages. The grouting requirement is characterized as minor if the relative length of tunnel sections which are assumed to require grouting is less than 10%, relative length of grouted sections of 11 - 20% is characterized as moderate, 21 - 30% as large and greater than 30% very large. The tunnel is expected to be excavated in rocks belonging to the Ryfylke schist group, the Karmøy ophiolite, the Torvastad group and the Precambrian basement. The grouting requirement in phyllite and greenstone belonging to the Ryfylke schist and the Torvastad group respectively is estimated to be minor, while it is considered to be minor to moderate in gabbroic rocks belonging to the Karmøy ophiolite and moderate in gneissic rocks belonging to the Precambrian basement. It is a general trend that the hard rock environment in the vicinity of large fault zones is commonly associated with areas with increased permeability, especially the jointed side rock of faults, the so called transition part. Due to their orientation in the in situ stress field, the side rocks of N - S trending faults are considered to have the largest grouting requirement. Results from a systematic prognosis shows that 66% of the total tunnel length is considered to have a grouting requirement which can be characterized as minor, while only 6% of the tunnel length is assumed to have a grouting

1 Institutt for geologi og bergteknikk Hovedoppgaver 2008 requirement which can be characterized as large or higher. The largest grouting requirement in the rock mass along the trace of the tunnel is considered to be in jointed side rocks of weakness zones and faults. A large part of the Rogfast tunnel will be under considerable water pressure. Norwegian subsea tunnels have been constructed successfully where grouting has been carried out against water pressures of 20 - 30 bar. Modern grouting equipment is capable of handling grouting pressures which are well above the water pressure expected in the Rogfast tunnel. Consequently it is assumed that grouting in the Rogfast tunnel will in general not be bound with any big problems. Circumstances may of course come up where grouting can be difficult because of difficult ground conditions. It is therefore very important that probe drilling ahead of the tunnel face is taken seriously so that possible problem zones are discovered in time. Norm for maximum allowable permanent water inflow into the Rogfast tunnel are briefly addressed. Due to the length of the tunnel it seems reasonable to suggest that a norm is set for the subsea section of the tunnel which is at the lower boundary of what has commonly been accepted before, or around 200 l/min/km. Under land in Randaberg and Vestre Bokn the tunnel passes natural areas which are considered to be sensitive to changes in groundwater level. Due to increase in environmental concern, lower norms are suggested for maximum allowable permanent inflow in the tunnel land.

Anders S. Bratholm (R. Sinding-Larsen)

OPECs prisscenarioer i forhold til fremtidig produksjon av syntetisk olje og dets konsekvens for norske produksjonsscenarioer. OPECs pricescenarios relative to the future global production of synthetic crude oil and its possible impact on existing Norwegian production scenarios. I en verden med stadig økt etterspørsel etter olje, fallende produksjonstall i flere land, samt høy oljepris over en lengre periode, fører dette til at substitutter til konvensjonell olje blir stadig mer aktuelt. Det finnes i dag gode alternativer, som lar seg konsumere med få eller ingen endringer. Et av alternativene er syntetisk olje som kan lages fra biomasse, gass eller kull. Disse omtales ofte som biomass-to-liquids (BTL), gas-to-liquids (GTL) og coal-to-liquids (CTL). Denne teknologien ble utviklet som et resultat av Tysklands behov for drivstoff under første og andre verdenskrig. Tyskland hadde ikke tilgang på olje, men forekomster av kull. Teknologi for å omdanne kull til olje ble derfor utviklet. I dag planlegges det flere fabrikker som skal starte opp produksjon av syntetisk olje. De landene som er mest interessert er USA, Kina, India og Sør-Afrika. Både USA, Kina og India har et høyt forbruk av olje og er nettoimportører av olje. Samtidig har disse landene rikelig tilgang på kull, noe som gir muligheter for stor innenlands produksjon av syntetisk olje fra kull. Ved å øke den innenlandske produksjonen av olje, vil disse landene få tilgang til olje til 26-45 dollar per fat, redusere sin avhengighet av produksjonslandene, samt redusere utslipp ved håndtering av klimagasser. Hovedutfordringen for produksjonen av syntetisk olje i dag, er usikkerheten rundt fremtidig oljepris. Dersom oljeprisen faller under produksjonskostnadene, vil produsentene av syntetisk olje tape penger. I tillegg er ikke all teknologien helt på plass, samt tilgangen til kvalifisert personell er begrenset. Dersom oljeprisen holder seg på et høyt nivå fremover, vil det være å forvente at produksjonen av syntetisk olje øker. Et økt tilbud av olje i markedet, vil føre til at prisene synker, eller ikke stiger like mye. Hvor mye prisene endres vil være avhengig av hvor stor den fremtidige produksjonen blir. For å finne den fremtidige produksjonen av syntetisk olje, brukes International Energy Outlook 2007. Denne rapporten benytter seg av tre ulike scenarioer, hvor prisbanene er en viktig driver for hvordan den fremtidige produksjonen av syntetisk olje vil bli. International Energy Agency (IEA) har anvendt forsiktige prisbaner i sine prediksjoner. Det forventes at høyere prisbane bør anvendes. Ved å bruke en lineær sammenheng mellom prisbanene fra IEA og egen prisbane, kommer det frem en annen prediksjon på syntetisk olje, som er høyere. Hvordan vil denne produksjonen av syntetisk olje påvirke Norges produksjon av olje? Norge går nå inn i en reduksjonsfase, hvor produksjonen faller år for år. I en slik fase er oljeprisen viktig. Høy oljepris vil gi muligheter til å bruke mer penger på forskning, teknologi, som igjen vil gi en økt produksjon. Motsatt fall om oljeprisen er lav. Norges forhold til Russland og politisk enighet om produksjon i omstridte områder som Barentshavet, Norskehavet og Jan Mayen, vil også være viktig for fremtidig produksjon på norsk sokkel. Oljedirektoratet har gitt ut en rapport som omfatter Norges fremtidige produksjon av olje, hvor det tas hensyn til fremtidig oljepris og spillerom og politisk enighet for aktørene på norsk sokkel. Det blir av Oljedirektoratet presentert fire ulike scenarioer. Disse er ”full gass”, ”teknolab”, ”stengetid” og ”blod, svette og tårer”. Hver av scenarioene representerer enten høy eller lav oljepris og høyt eller lavt spillerom og politisk enighet på norsk sokkel. Som grenseverdi for om oljeprisen blir høy eller lav, anvendes referanseprisbanen gitt av EIA i ”IEA World Energy Outlook 2006”. Dette gir at

2 Institutt for geologi og bergteknikk Hovedoppgaver 2008 dersom oljeprisen faller under 55-60 2005-dollar per fat, vil lavprisscenarioene slå til. Spillerommet og politisk enighet er gitt av Norges hensyn til miljøet og forholdet til Russland. Hvorvidt den økende produksjonen av syntetisk olje vil påvirke oljeprisen fremover, blir bestemt av FRISBEE-modellen utviklet av Statistisk Sentralbyrå (SSB). Bruk av FRISBEE-modellen gir et kvantitativt anslag av endringseffekter gitt av et økt tilbud av olje til markedet fra syntetisk olje. I masteroppgaven sammenliknes referansescenarioet til SSB med scenarioet som inneholder et økt tilbud gitt av syntetisk oljeproduksjon. Basert på det økte tilbudet av olje til markedet, gir FRISBEE-modellen en lavere oljepris enn for refransescenarioet. FRISBEEmodellen gir sammenliknet med referansescenarioet en oljepris som er 6,41% lavere i 2010, 9,97% i 2015, 12,22% i 2020, 13,78% i 2025 og 14,93% i 2030. På bakgrunn av prediksjon gitt av EIA, med korrigert prisbane og FRISBEE-modellen, samt Oljedirektoratets antagelser gitt i ”Ressursrapporten 2007” konkluderes det med i masteroppgaven at Norges fremtidige produksjon ikke vil bli påvirket av produksjon av syntetisk olje. Det forventes derfor at Norges produksjon går inn i høyprisscenarioene til Oljedirektoratet, og at fremtidig produksjon på norsk sokkel vil avgjøres av politisk enighet om produksjon i omstridte områder som Barentshavet, Norskehavet og Jan Mayen.

Dyveke Bjørgum Brodal (S. Lippard)

Et termal-stratigrafisk rammeverk og 3D termal-modellering i den norske delen av Nordsjøen. A thermal stratigraphic framework and 3D thermal modelling in the Norwegian North Sea. The thesis study area consists of a large part of the SE Norwegian North Sea centered around the Stord and Egersund basins. The thesis consists of a literature study of the area and the creation of a thermal stratigraphic work for use in a modelling part, the main emphasis of the work has been the thermal stratigraphic work. The thermal stratigraphic framework attempts to relate successions of lithofacies and their boundaries such that facies with similar thermal properties are grouped together. When creating the present model, a good knowledge of the geology in the area is considered important because the thermal conductivity in many cases varies laterally through a layer with the change in facies, and the thermal conductivity has an impact on the heat flow. The modelling work is performed using the IES PetroMod package. The modelling shows that Upper Jurassic source rocks are immature and marginally mature in most of the study area, and discusses the possibility of deeper layers as possible source rocks. The modelling also shows that because of extensive, late Neogene erosion the area is not in thermal equilibrium.

Chandra, Sharad (B. Nilsen)

Engineering Geological Analysis of Tapovan Vishnugad Hydropower Project in Himalayan Region, India. The present study relates to detailed engineering geological analysis of a hydropower project in Himalayan rock mass conditions. It primarily underscores and emphasises upon the aspects of stability and rock support requirements in the similar geologic region as of Himalayas. As special case for this study, Tapovan Vishnugad Hydropower project in India has been analysed. Tapovan Vishnugad is a 520 MW run-of-river project which is planned with an 11.664 km long headrace tunnel, 586 m long pressure shaft, 122 m x 22 m x 50 m large underground powerhouse cavern and a 513 m long tailrace tunnel. The contact for the construction of the project has already been awarded and the construction activities are expected to commence in very near future. The evaluation and discussion of engineering geological condition for all project components has been carried out with respect to engineering geological mapping performed for preparation of detailed project report. In addition to evaluating the alignment and site layout, design aspects of project components have also been touched upon which includes evaluating orientation of tunnel axis, shape and size of tunnels, minimum overburden (rock cover over tunnel crown) requirement along the HRT, pressure shaft and power house. Power house has been evaluated in respect of its long axis orientation, its shape and dimension, etc. The alignment, site layout and project design has generally been found in order. The fragile and young Himalayas exacerbate some special challenges for underground excavation works. The challenges may be compounded due to natural phenomena like monsoon rainfall, high seismic activities, etc., as well as due to man made activities like deforestation, excessive drawdown of water table, etc. Some of the prominent special challenges dealt in detail in the present study for Tapovan Vishnugad hydroelectric project are choice of excavation method for HRT, rock stresses, seismicity, landslides and slope stability, groundwater and permeability condition, geothermal interferences, and availability of construction material and equipments. The solution to deal with the problems has also been suggested.

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To decide upon the excavation method time and cost prognosis has been carried out for drill and blast method vis-á-vis TBM excavation method. Comparison of weekly advance rate and cost per meter indicates a clear edge for adoption of TBM method. However, the aspects need to be revisited after precise determination of rock mass characteristics viz. DRI, BWI, CLI, etc. Further, for firm conclusion, detailed investigations related to joints/weakness zones, porosity of rock mass, stress situation, etc. are required. The three main prevalent practices for support design in case of underground works are past experience based, rock classification systems and numerical analysis. All three methods have been employed to predict the rock support requirements for head race tunnel and power house cavern. This provided a sound basis for comparison and discussion upon the three methods. The merits, demerits, differences, limitations, etc. of each method have been discussed in detail. Numerical modeling has an added advantage for the analysis of rock supports and stability of the tunnel. The Phase2 code has been adopted and the Hoek- Brown Failure criterion has been used to determine the state of stress, strength factor and displacement around the periphery of the tunnel and powerhouse cavern. Two sections of headrace tunnel representing different rock quality, overburden and stress conditions have been analyzed. However, it needs to be realized that numerical modeling is a mere tool and its result needs thorough and precise interpretation. Also, the results from numerical analysis can never be better than input parameters. Hence, the emphasis on improving the quality of input data should always be there. All analytical methods as well as classification system require sound engineering geological judgment and knowledge of actual ground conditions. Hence, the experience can also not be substituted. Finally, based on the analyses, recommendations have been made for rock support, further engineering geological investigations required and monitoring during construction. Particular emphasis needs to be given for in-situ stress measurements and identification of areas with groundwater problem. Before zeroing on the excavation method for HRT, we need to learn lessons from Dulhasti experience. As far as method to be adopted for rock support design is concerned, each needs to be applied critically and preferably in conjunction as results by one method supplements the results of other method. None of the method is conclusive and at best can only complement each other. Back analysis and 3-D modeling are recommended for further refinement of modeling parameters.

Dammyr, Øyvind B. (B. Nilsen)

Analyse av effekten av sprøytebetong som bergsikring i vegtunneler. Analysis of the effekt of shotcrete for rock support in road tunnels. The aim of this master thesis has been to analyze the effect of shotcrete as rock support in road tunnels. How zones of weak rock containing swelling clay can be supported has been the main goal of the assignment, primarily by looking at the behaviour of reinforced ribs of sprayed concrete under these weak rock conditions. How to design the reinforced ribs has been part of the research together with looking at the potential for ribs to replace cast concrete in the weakest type of rock. Zones of weak rock in four road tunnels under construction have been visited and clay samples collected. An evaluation of each of the zones stability has been undertaken by looking at rock support in place, tunnel mapping and results from clay analysis. Numerical modeling of the weak zones has also been performed in the program Phase2. The results show promising correlations to the recommendations made by the Q-system for designing reinforced ribs of sprayed concrete. Test results of clay samples taken from the same weakness zone display great variations in swelling capacity. This indicates large local variations and/or uncertainties linked to the test method.

Forseth, Karen K. (B. Brattli)

Ramsund – Miljøkartlegging og tiltaksvurdering. Forurensede sjøbunnsedimenter. Environmental mapping and evaluation of an action program for polluted marine sediments at Ramsund. I Ramsund er det per i dag gjeldende kostholdsråd som en følge av forurensning av PCB og TBT. Forsvarsbygg fikk i 2005 pålegg fra SFT om å utføre nødvendige tiltak i Ramsund slik at kostholdsrådet kan oppheves. I den forbindelse har Multiconsult AS fått i oppdrag å gjennomføre en omfattende miljøundersøkelse for å kartlegge forurensningen, samt å gjøre en videre vurdering av tiltak for å bedre miljøkvaliteten. Feltarbeidet i Ramsund ble gjennomført i oktober 2007. Det ble da tatt sedimentprøver ved til sammen 428 prøvestasjoner fordelt på tre områder. I tillegg ble det gjort strøm- og turbiditetsmålinger, og samlet inn materiale til

4 Institutt for geologi og bergteknikk Hovedoppgaver 2008 toksisitetstester. Sedimentprøvetaking ble gjort med grabb, pistoncorer eller prøvetakingssylindere. Prøvene ble sendt til laboratorium og analysert for PCB, TBT og metaller samt innhold av organisk materiale. Analyseresultatene er sammenstilt, og det er gjort en risikovurdering, trinn 1. Sammenstillingen og risiko-vurderingen viser at deler av sedimentene i Ramsund ligger i tilstandsklasse III – V, moderat til svært dårlig miljøkvalitet. Risikovurdering, trinn 2, viser at det er nødvendig med gjennomføring av tiltak for å bedre miljøkvaliteten i sedimentene, og for videre å kunne oppheve det gjeldende kostholdsrådet. Resultatene fra toksisitetstestene viser veksthemmende effekter i både porevann og ekstrakt i noen av prøvene. Analyseresultatene finnes presentert i tabeller og ved hjelp av temakart. Ulike tiltak for å bedre miljøtilstanden i sjøbunnsedimenter er gjennomgått på generelt grunnlag før det videre er gjort en enkel tiltaksvurdering for Ramsund. Sundet er delt inn i fem ulike områder hvor det er behov for tiltak. Forholdene i de fem områdene er ulike med hensyn til forurensningsgrad, sedimenttype og strømforhold. Mudring foreslås i tre av de fem tiltaksområdene, mens vanlig tildekking og tynntildekking foreslås i de resterende to områdene. Av mudremetoder inngår både hydraulisk og mekanisk mudring. Mudrede masser foreslås deponert i dypvannsdeponi, eller behandlet ved biologisk nedbrytningsanlegg. Geotekniske vurderinger er ikke gjort i rapporten. Gjennomførte tiltak bør følges opp av en periode over flere år med måling og overvåking for å vurdere tiltakenes effekt på spredning av forurensning og innholdet av miljøgifter i fisk og skalldyr.

Halsne, Svein Magnus (E. Broch)

En teknisk-økonomisk analyse av injeksjonsarbeidene utført i jernbanetunnelene på strekningen Skøyen - Asker. A technical-economical analysis of the grouting works carried out in the railway tunnels between Skøyen and Asker. Jernbaneverkets pågående utvidelse av jernbanesporet mellom Skøyen og Asker inkluderer Bærumstunnelen, totalt ca. 5,5 km. Fare for grunnvannssenking fører til at det stilles store krav til tett tunnel og dermed nød-vendige injeksjonsarbeider. Tunnelene går hovedsakelig i Oslofeltets sedimentære bergarter. Disse bergartene er vanligvis relativt tette, med tynne, ofte leirfylte sprekker og har erfaringsmessig vært vanskelige å tette. For å nå kravet om maksimum 4 liter innlekkasje per minutt per 100 m tunnel er det lagt opp til et omfattende injeksjonsopplegg. Det skal gjennomføres systematisk forinjisering langs hele traséen. Injeksjonen utføres med industrisement i et stort antall injeksjonshulll (foreløpige skjermer er på 75 hull). Dette injeksjonsopplegget står i kontrast til det Jernbaneverket utførte i de to ferdigstilte tunnelprosjektene (JA-tunnelene) Skaugum- (2004) og Tanumtunnelen (2005) noen få kilometer mot øst på den samme jernbanestrekningen. I disse tunnelene ble det med samme tverrsnitt og tetthetskrav injisert fra betydelig færre hull mens injeksjonen ble utført med en kombinasjon av mikrosement og industrisement. Der injeksjon med industrisement tidligere er brukt hovedsakelig for tunneler med lave tetthetskrav og lettere injiserbart fjell, brukes det nå nesten utelukkende industrisement i Bærumstunnelen, som har strenge krav og relativt vanskelig injiserbart berg. Dette kan gjennomføres ved å bruke høye trykk, lave v/c-tall og tett injeksjonsskjerm. Potensialet er stort for å spare kostnader ved rimeligere massekostnader. Foreløpige arbeider har vist at dette injeksjonsopplegget ved normale forhold sannsynligvis gir tilfredsstillende tetteresultater. Det har vært noe større behov for kontrollskjermer enn i JA-tunnelene. Foreløpig har metoden gitt dårligere tetteresultater ved lav overdekning, og muligens også ved vanskelige forhold som svært tett oppsprekning. Det har derfor vært behov for å justere metoden betydelig, eventuelt utføre gjentatte skjermer når slike forhold oppstår. Injeksjonsmetoden ved JA-tunnelene var ved slike forhold mer anvendbar. Massekostnadene per kilo er betydelig lavere ved bruk at industrisement samtidig som masseforbruket muligens blir noe høyere. Massekostnadene vil likevel sannsynligvis bli betydelig lavere i Bærumstunnelen. Det er brukt en tettere injeksjonsskjerm enn ved tilsvarende tetthetskrav på JA-tunnelene. Foreløpig erfaring viser at tetteresultatene likevel ikke ser ut til å ha blitt bedre. Dette kan derfor tyde på at den tettere skjermen i noen grad kompenserer for billigere injeksjonsmasse. På grunn av tettere injeksjonsskjerm blir tidsforbruket og mengdene injeksjonsboring i Bærumstunnelen noe høyere enn for injeksjonsmetoden i de tidligere tunnelprosjektene. Forskjellen i kostnadsfordeling mellom de to metodene er hovedsakelig større massekostnader ved JA-tunnelene og større borekostnader i Bærumstunnelen. Størrelsen på kostnadene vil avhenge mye mellom entreprenører og kontraktsbetingelser. Det kan som følge av de utførte kostnadsberegninger se ut til at metoden som er benyttet i Bærumstunnelen gir noe høyere kostnader enn metoden i Jong - Asker hadde gitt. Gjeldende injeksjonsmetode i Bærumstunnelen gir lenger injeksjonstid på grunn av mer injeksjonsboring. Den foreløpige analysen av injeksjonsmetoden i Bærumstunnelen gir grunnlag for å hevde at injeksjonsarbeidet ved JA- tunnelene ga like god måloppnåelse med gunstigere økonomisk og tidseffektiv metode.

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Hauge, Lene (S.O. Johnsen)

Petroleumleting i Gjallarryggen, Norskehavet. Petroleum Exploration in the Gjallar Ridge, Norwegian Sea. The Vøring Basin in the Norwegian Sea has undergone several extension and subsidence episodes. The most important extension phase took place during late Middle Jurassic to Late Cenomanian, creating the deep basin area and gave rise to prominent structures. The Gjallar Ridge is one of these structures, an area of tilted and eroded fault blocks located in the west of the Vøring Basin, Norwegian Sea. One of the main areas of uncertainty concerning hydrocarbon exploration in the Vøring Basin is the question of reservoir presence. Provenance studies play a key role in the exploration of the region, since reservoir presence is partly governed by location of the clastic source regions. Potential sources of coarse clastic sediments lie both to the east in Mid-Norway, and to the west in East Greenland. Throughout the Late Cretaceous the faults of Gjallar Ridge were periodically active, forming the Fenris Graben in the west and the Vigrid Syncline in the east. The Surt and Bivrost Lineaments were the main sand entry points with a pronounced sedimentation of basin-floor turbidite systems of the Nise and Springar Formations during the Late Cretaceous times. The North-East Greenland are interpreted to be the provenance area of these Campanian-Maastrichtian deposits. Two possible prospects/leads have been mapped and evaluated. Lead 1 is a stratigraphic trap with the reservoir in the Maastrichtian Springar Formation located in block 6705/10 and 6705/11. It is situated on the eastern flank of the Gjallar Ridge leading into the Vigrid Syncline. Lead 2 is a structural trap with a fault and a three-way dip closure, located in block 6705/10 in the Nise sandstone. The reservoir is situated in a rotated fault block in the center of the ridge. Both of the leads have been risked and volume calculated.

Hovland, David (C. Li)

Numerisk analyse av samvirket mellom berg og bolt i kullgruven Svea Nord. Numerical Analysis of the Interaction between Bolts and Rock Mass at the Svea Nord Coal Mine. Sommeren 2007 ble målestadjon 5 installert i DT2 tv 7 + 30 m. Stasjonen som besto av instrumenterte bolter og ekstensometere, ble montert på stuff i gruva. Etter som det forelå gode data fra målinger i felt, var det et ønske å benytte disse verdier i en numerisk modell som simulerte samvirket mellom berg og sikringssystemet i gruva. Tanken var at dersom en god kalibrert numerisk modell forelå, ville endringer i sikringssystemet i den samme modell kunne gjenspeile effekten av endret sikringssystem i virkeligheten. Etter som de mekaniske egenskapene til bergartene forandres fra sted til sted i gruva, ble det utført kjerneboringer i nærheten av målestasjonen. Formålet med boringene var å kartlegge geologien samt å skaffe tilveie kjerneprøver av sandsteins- og leirsteinslaget som senere skulle testes av SINTEF. Mekaniske verdier for kullaget ble anslått ut fra tidligere utførte laboratorieforsøk på kullaget i Svea Nord. De mekaniske verdier for bentonittlaget ble anslått ut ifra litteraturstudier. Resultatene fra laboratorieforsøkene på de ulike bergartene ble benyttet som inngangsparametere i formelverket som er utledet for å gjøre et estimat av bergmasseverdier til de ulike bergartene i modellen. De utregnede verdier ble så benyttet videre i PHASE 2D. Den numeriske modell som ble konstruert i dette programmet, representerte et vertikalt snitt gjennom målestasjon 5. Modellen ble bygget med tilsvarende lithologiske grenser som ble kartlagt mellom tv 7 – 8 i DT2B. Spenninger i modellen ble anslått med basis i en rekke spenningsmålinger utført i gruva. Inngangsparameterne for sikringssystemet ble anslått ut ifra data fra produsentene av boltene. Etter en rekke kjøringer av modellen i PHASE 2D, kom forfatter frem til et sett med residualverdier som medførte at den numeriske modell stemte godt overens med data innsamlet fra gruva. Etter at den kalibrerte modellen forelå, endret forfatter boltemønsteret. Endret bruddutvikling ble så studert for hvert tilfelle med endret sikringsmønster. Vesentlige konklusjoner fra denne analyse er at det registreres en markant øking i aksiell pålastning på boltene i og under svake bergartslag som kull og bentonitt. Ut fra den numeriske analysen i PHASE 2D, vil bruk av en senterbolt i hengen medføre at det er mulig å gå ned fra seks til fem bolter i hengen, uten at dette får konsekvenser for dannelsen av brudd rundt tverrsnittet av stollen. Det er ikke påvist noen betydelig endring i bruddutvikling ved å endre stikning på boltene som er montert mot sidepallene i hengen. For å studere den tredimensjonale effekt av hvordan deformasjon og spenninger endres etter som stuffen driver seg inn i kullaget, har forfatter valgt å modellere sikringssystemet i FLAC 3D. Resultatet fra modelleringen viser omtrent samme spenningsfordeling og deformasjonsutvikling som ble observert i PHASE 2D. Forfatter anser at et av de viktigste resultat fra analysen i FLAC 3D, er plottet som beskriver utvikling av deformasjon i heng og sidepall i utvalgte punkter ved målestasjonen før og etter passering av stuffen. Deformasjon som oppstår i sidepallen, indikerer at sidepallen stabiliseres like etter at stuffen passeres. Resultatet kan benyttes for å støtte opp om at dagens sikringssystem i

6 Institutt for geologi og bergteknikk Hovedoppgaver 2008 sidepallene fungerer tilfredsstillende. Dette fordi kamstålboltene i sidepallene i gruva stikker 15 cm lenger inn i sidepallen, enn boltene i de numeriske modellene. Resultatene fra de numeriske modeller, indikerer derfor at det er mulig å korte ned dagens kamstålbolter med opptil 15 cm.

Hugaas, Espen (R.A. Kleiv)

Nasa Kvarts – Vurdering av ulike kvaliteter for optisk sortering. Optical Sorting of Nasa Quartz – An Evaluation of Different Feed Qualities. For å imøtekomme en økende etterspørsel etter råmateriale til produksjon av rent silisiummetall, er den hydrotermale kvartsforekomsten Nasafjell blitt nærmere undersøkt av Elkem. Forekomsten består av to linser, der den vestlige er mest aktuell for drift. Tidligere undersøkelser konkluderer med at kvartsen har en kvalitet som gjør den interessant med tanke på anvendelse innenfor silisiummarkedet. En høyaktuell oppredningsteknikk for denne typen materiale er optisk sortering. Dette er en automatisering av den tradisjonelle, manuelle håndskjeidingen. Siden 1950-tallet er det utviklet en rekke sofistikerte løsninger som stadig effektiviserer sorteringsprosessen, og i dag dominerer bruk av digital fototeknikk og pneumatiske ventiler i det kommersielt tilgjengelige utstyret. Kvarts fra Nasa varierer i utseende, og det er absolutt mulig å definere optiske skillelinjer i materialet. Det er gjort en undersøkelse som belyser sammenhengen mellom den optiske kvaliteten og den kjemiske kvaliteten. Korrelasjonen er ikke perfekt, men det fremkommer en viss sammenheng mellom de ulike kvalitetsparametrene, noe som bygger opp under påstanden at Nasa-kvartsen kan sorteres optisk i en automatisert prosess. Da en del av kvartsmaterialet naturligvis vil sorteres bort i forhold til de primære råstoffkravene, er potensialet for eventuelle b-produkter undersøkt. Kvarts benyttes som råstoff i en lang rekke prosesser og det bør absolutt være mulig å finne bruk også for Nasas lav-kvalitets materiale. I forhold til kjemiske kvalitetskrav er også dette materialet godt nok for flere bruksområder, herunder glassproduksjon. Forekomstens beliggenhet gjør det imidlertid vanskelig å slå fast om det er et marked for eventuelle b-produkter fra Nasa med de priser som dominerer i dag. Mye av urenhetene i materialet fjernes ved hjelp av kjente teknikker, men dette medfører at materialet må males ned til svært fine fraksjoner. Dette er ikke aktuelt for kvarts til smelteformål, men kan være aktuelt om bruken er produksjon av for eksempel glass, keramiske produkter eller silisiumkarbid.

Kleppe, Henriette Indine (M. Thornhill)

Undersøkelse av en pilot anaerob SRB våtmark rensepark i Folldal. Monitoring of a pilot scale anoxic SRB treatment system in Folldal, Norway. The Folldal Mines have a history of mining in sulphide ore for about 250 years. Waste rock dumps, tailing deposits and polluted mine water all contribute to elevate metal concentrations and acidity, also called acid mine drainage (AMD), in the run off from the area even after closure. The Directorate of Mining with the Commissioner of Mines at Svalbard (the Directorate) have accepted the responsibility to reduce the AMD in Folldal to meet a new pollution command from the Norwegian pollution Control agency (SFT). In fall 2006, the Directorate initiated the construction of a pilot treatment system in Folldal. The system is designed as a constructed anoxic (anaerobe) wetland and is in addition inoculated with sulphate reducing bacteria (SRB). The SRB uses simple carbon compounds and excess sulphate in the mine water to form sulphides that facilitates precipitation of metal sulphides. Results from monitoring of this pilot system since start-up until October 2007 are discussed in this report. The main purpose for this report is to ienvestigate the fate of copper and iron in the system and to find out if the environment in the basins is reducing. Measurements of Eh and the ratio Fe(II)/Fe(III) indicate that the basins are developing a reducing environment and that Fe(II) dominates over Fe(III) throughout the system. Episodes of clogging of the system have lead to varying retention times. This has shown to have a significant effect on copper removal as copper removal increases as the retention time increases followed by a decrease in copper removal as the waterflow reinitializes. The varying retention times has complicated the interpretation of the effect of seasonal variations and copper loading on copper removal. However, the last measurements show an increasing copper removal as copper concentrations in the influent are relatively high and stable. The average percentual removal for cations is: 25% for Al, -62% for Pb, 25% for Cd, 17% for Ni, 25% for Zn, 35% for Cu and 20% for Fe.

7 Institutt for geologi og bergteknikk Hovedoppgaver 2008

Lu, Hui (L. Blikra)

The Nordnes rockslide – Analysis of monitoring data and deformation mechanisms.

The purpose for this master thesis is generally to try to understand the deformation and sliding pattern of the Nordnes rockslide based on monitoring instruments. The main instruments are crackmeters, tiltmeters and lasers, but other monitoring instruments are also taken as a reference. In order to understand the deformation pattern, geology at the Nordnes site has been introduced. By describing engineering geology factors of the site, the failure mechanism sliding compression cracking has been considered as the main failure type. The rockslide is also compared by another large-scale rockslide, the Åknes rockslide in western Norway. In order to understand the deformation monitoring data better, instruments and other affecting factors have been well studied. Firstly, basic principles of instruments have been introduced, which can help us to know their characteristics better; secondly, the identification of installation position and orientation as well as installation notice is critical to the later analyses. The last and most important factor is the understanding of error and bias information, which includes errors of the data, temperature variation and unsure part. Temperature variation has been emphasized. The correlation coefficient of deformation and temperature change has been calculated, and in order to understand average temperature change per deformation change, statistical methods have been used, by assuming a linear trend. Due to the sunshine on instruments, the relationship between large degree and small degree variation has also been studied. By combining the 2 points mentioned above, deformation or tilting obtained by monitoring instruments have been plotted on structure map. Interpretations have been carried out for the individual instruments and by combining different instruments. Both possible interpretation and contradiction have been listed. Finally, based on monitoring data, the unstable area has been classified into 4 different clusters, and the characteristics of each cluster have been specified.

Lundli, Anders (M. Thornhill)

Vurdering av avgangsmasser fra Hustadmarmor AS for tildekkingsformål ved Fiskerstrand Verft. An Appraisal of Waste Materials from Hustadmarmor AS for the Purpose of Remedial Covering of Contaminated Sediments at Fiskerstrand Verft. Hustadmarmor AS er verdens største produsent på kalsiumkarbonat til papirindustrien. Under produksjon dannes det store mengder avgang som Hustadmarmor AS er interessert i å finne alternative bruksområder for. I denne sammenheng holder Hustadmarmor AS på med et omfattende arbeid for å undersøke om avgangsmassene deres er egnet for tildekking av forurensede sjøsedimenter. Dette arbeidet gjøres opp mot SFT sin veileder ”Veiledende testprogram for masser til bruk for tildekking av forurensede sedimenter” [Eggen et al. 2005]. Dette er en veileder på fire trinn der de to første trinnene består av mer generelle undersøkelser for godkjenning av massene. Undertegnede har jobbet opp mot denne veilederen i sin prosjektoppgave og gjennomført påkrevde undersøkelser i de to første trinnene. Denne masteroppgaven er en direkte fortsettelse på dette arbeidet og tar for seg de to siste trinnene i veilederen. Hustadmarmor AS har innledet et samarbeid med Fiskerstrand Verdt som ligger i Sula kommune da sedimentene utenfor verftet (Kavlesundet) er svært forurenset som følge av verftsaktiviteten på stedet. Det er utformet en tiltaksplan for området og en tildekking av sedimentene anbefales som behandlingsmetode. Det er foretatt stedsspesifikke vurderinger som blant annet strømningsmålinger og en topografisk kartlegging i Kalvesundet i forbindelse med trinn 4 av veilederen. Fra resultatene produsert i denne masteroppgaven kommer det frem at massene fra Hustadmarmor AS innehar flere gode egenskaper som tildekkingsmateriale. Det ble påvist at ved å dekke til forurensede sedimenter med et tynt masselag ble mengden diffundert PCB og PAH redusert voldsomt. Det ble også utført ristetester på forurensede sedimenter blandet med masse fra Hustadmarmor AS. Testene viste en tydelig reduksjon i utlekket mengde tungmetaller, PAH og PCB, men en overraskende økning i utlekket TBT. Det er en problemstilling når det gjelder innholdet av flotasjonskjemikalier i massene til Hustadmarmor AS da SFT på det nåværende tidspunkt ikke vil anbefale massene for tildekkingsformål pga. dette innholdet. Dette diskuteres utfyllende i denne masteroppgaven.

Moen, Bjørnar R. (B. Nilsen)

Åknes skredområde – Analyse av mulig effekt av dreneringstiltak. Åknes Landslide Area – Analysis of possible effects of drainage. Masteroppgaven er en fortsettelse av prosjektoppgaven som ble skrevet andre semester 2007. Oppgaven er rettet mot Åknes/Tafjord prosjektet, med hovedvekt på vurdering av drenering som stabiliserende tiltak.

8 Institutt for geologi og bergteknikk Hovedoppgaver 2008

Hoveddelen i oppgaven er en stabilitetsberegning for å se på effekten av en eventuell drenering av Åkneset. Beregningene er kjørt i analyseprogrammet SLIDE, hvor en todimensjonal modell av fjellsiden er lagt inn. På grunn av stor usikkerhet ved parametere og antagelser, er det valgt å bruke tre ulike sett med antagelser. Dette viser først og fremst hvor stor betydning inngangsparameterne har for resultatet, men det viser også at drenering vil ha stor betydning uansett hvilke parametere som ligger til grunn. Det er gjort antagelser om andelen intakt fjell i skredområdet. Beregningene viser at andelen fast fjell har stor betydning på sikkerhetsfaktoren. Stabilitetsberegningene viser at drenering maksimalt kan øke sikkerhetsfaktoren 27% slik dreneringsløsningene er skissert. Ved bruk av bare dreneringstunneler vil aldri så stor effekt kunne oppnås, men om bare halvparten av dette oppnås, vil det trolig ha stor betydning for bevegelsene. Dreneringsalternativ 3 gir den største effekten og anbefales som det beste alternativ. Videre i oppgaven er det med et nytt kostnadsestimat og en vurdering av sprengningsrystelsenes effekt på skredområdet. Kostnadsestimatet er en oppdatert utgave av det som ble lagt frem i prosjektoppgaven. Det gamle estimatet var for lavt på flere punkter som er rettet opp i det nye. Det er fortsatt en del usikkerhet rundt noen poster i kostnadsberegningen, men den bør gi en pekepinn på kostnaden knyttet til byggingen av selve dreneringsløsningen. Kostnadene for alle tre alternativene er beregnet til å bli i overkant av 100 millioner kroner. Den delen som havner utenfor selve anleggsaktiviteten er ikke tatt med. Rystelsene er vurdert til å være det største usikkerhetsmomentet ved en eventuell bygging. Det er derfor gjort en del beregninger av rystelsene fra sprengninger under skredområdet. Beregningene baserer seg på generelle formler og antagelser og disse kalibreres før nøyaktige data kan legges frem. Med de muligheter som finnes for å redusere rystelsene fra tunnelsalver vurderes det slik at rystelsene trolig ikke blir noe problem for driving av en tunnel under skredmområdet. På grunn av debatten som går angående valg av sikringsløsning er det tatt med noen vurderinger og beregninger rundt de alternative løsningene til drenering. De analysene som er gjort viser at det ikke finnes noen andre realistiske løsninger enn drenering. Grunnen til dette er at de mer eksterne forslagene til løsning stoppes av økonomiske, praktiske eller tidsmessige faktorer. Selv med ubegrensede økonomiske rammer virker bruken av fjellanker eller nedsprengning urealistisk.

Nag, Silje (B. Brattli)

Tynn tildekking av forurensede sedimenter – småskala diffusjonsforsøk og modellering av diffusjon gjennom ulike dekklagsmaterialer. Thin-layer capping of polluted sediments. Microcosm diffusiontests and modelling of diffusion through caps of different materials. Four materials were examined with respect to their ability to reduce diffusive flux of PAHs and PCBs from a polluted sediment, when applied as a thin cap on top of the sediment. The material were a lime slurry consisting of fine-grained by-product from marble production by Hustadmarmor AS, a gypsum slurry from NOAH, marine clay, and pulverized activated carbon (AC). A laboratory microcosm test was utilized to measure the diffusion of native PAHs and PCBs from a polluted sediment during 101 days, in the presence and absence of 0,5 centimeters thin capping layers of the different materials. Diffusive flux was also modelled and calculated by using measured parameters from the sediment and capping materials. A comparison between measured and calculated diffusive flux was performed as a quality insurance of the data. Steady state diffusive flux from uncapped sediment proved to be linear for most compounds, and were 1384 ± 88 and 5,6 ± 0,6 ngm-2 dag-1 for sum PAH 15 and sum PCB 7, respectively. Average steady state diffusive flux were overestimated in the microcosm test compared to calculated flux by 20 prosent for PAH, and 425 prosent for PCB. Diffusion through capped sediments only occurred when the capping layer consisted of clay. The lime slurry, gypsum slurry and AC had enough sorption capacity to prevent PAH and PCB from breaking through the cap during the test period. A comparison of measured and modelled diffusive flux proved that the sorption abilities of clay and gypsum slurry employed in the modelling were underestimated. This was anticipated to be due to the calculation of distribution coefficient between the compounds and the capping material based on TOC values, rather than BC values. Steady state diffusive flux from sediments capped with 0,5 centimeters thin caps of the different materials, was calculated to be reduced by 75 percent compared to uncapped sediments. Based on modelling and laboratory tests, it was assumed that AC was superior to the other materials with respect to sorption abilities towards PAHs and PCBs. Lime slurry and gypsum slurry were assumed better sorbents than clay.

9 Institutt for geologi og bergteknikk Hovedoppgaver 2008

Which material best fitted for thin capping of polluted sediments, depend upon different factors such as the purpose of the action, economy, availability, how the material can be handled, and site-specific conditions.

Ongstad, Andreas (C. Li)

Vurdering av spenningsforhold i planlagte Toventunnelen. Estimate of rock stress conditions in the planned Toven tunnel. En vurdering av spenningsforhold i planlagte Toventunnelen er gjort ved hjelp av numerisk modellering. Fjellryggen tunnelen skal gå igjennom vil resultere i en overdekning på opptil 556 meter, og erfaring fra andre tunneler i liknende forhold tilsier at høye horisontalspenninger parallelt fjellryggen kan medføre stabilitetsproblemer i form av sprakefjell, avskallinger og bergslag. Bergmassen i Tovenfjellet består av, og er modellert med, porfyrisk granitt og glimmerskifer, gjennomsatt av marmorganger og en rekke knusningssoner. Grunnlagsmaterialet for bestemmelse av inngangsparametere i modellene er hovedsakelig materiale samlet ved litteraturstudier, supplert med bergmasseklassifisering fra befaring på Rv. 78 og bergmekanisk testing av innsamlede prøver av granittiske bergarter. Det endelige elementprogrammet Phase2 er benyttet som analyseverktøy, og som bruddkriterium er det generelle Hoek- Brown kriteriet valgt. Et in situ spenningsprofil i lengderetning er simulert sammen med fire tverrsnittprofiler, og stabiliteten er vurdert for forskjellige bergmassekvaliteter og spenningsscenarioer. Basert på primærspenningsscenarioet med største horisontalspenning orientert parallelt fjellryggen, viser resultatene at store spenningskonsentrasjoner vil kunne skapes i tunnelens heng og hjørner. Lokale geologiske strukturer som knusningssoner, bergartsgrenser og marmorsoner vil imidlertid påvirke spenningsbildet og lede deformasjonene. Bruk av spenningsnivåkriterier indikerer et spenningsnivå som tilsier at moderat til kraftig avskalling kan finne sted i porfyrgranitten etter kortere til lengre tid. Vurdering av muligheten for utglidninger av blokker fra knusningssonene tunnelen krysser, viser at potensielle utrasninger ved gitt spenningstilstand kan forekomme. Modellering med sikringsmidler sier lite om samvirke mellom sikring og berg, og hva de har å si for stabiliteten av svakhetssoner og høyspent kompetent berg. Sammenligning gjort med to andre tunneler med horisontale spenningsproblemer i henget indikerer et noe høyere spenningsnivå i Toventunnelen. Manglende kalibreringsdata for Toventunnelen gjør det imidlertid vanskelig å si noe konkret om hvor omfattende bergslagsaktiviteten kan komme til å bli.

Mohmmad M. Rahman (S. Lippard)

1D and 2D PetroMod Basin Modelling of the Northern North Sea. This master‟s thesis project is carried out during the spring semester from February to June, 2008. 1D and 2D basin modelling, together with seismic interpretation, has been done on a regional seismic line (NVGT 88-08) of the Northern North Sea. The report presents the basin development from a structural point of view and includes the results of thermal and maturity history using numerical tools of basin modelling. The stratal architecture of the study area was reconstructed based on seismic and data from three wells to correctly account for the complex tectonic and thermal history. The burial history shows that the basin developed in 4 phases of subsidence episodes. The basin started to form in Permo-Triassic time. At the end of Jurassic, crustal stretching accelerated in the Viking Graben caused rapid subsidence of large rotational fault blocks, the development of a submarine relief and local uplift of footwall blocks above the erosional base level. The rifting activities come to an end during the early Cretaceous and the basin was then affected by thermal subsidence and sediment loading. Progressive infilling of sediments and shallow water conditions prevailed up to Pliocene when thick prograding sediments was deposited in the proximal and distal parts of the basin. The major source rock system is the Upper Jurassic marine shale. Modelling results indicate that this reached its maximum temperature at about 200°C in the deeper part of the basin. Transformation ratio of the source rock shows that it reached its maximum maturity during the Early Palaeocene to Eocene. Oil generation reached its maximum level of maturity and consequent expulsion at the end of the Eocene. During middle to late Tertiary, significant gas generation in the Upper Jurassic shale occurred when higher formation temperatures were attained. Overall, the source and reservoir rock of the study are shown a significant prospectivity of hydrocarbon generation and accumulation. Calculated reserves of the study area, roughly estimated by the Petromod software, are about 1180 MMbbls of oil in subsurface condition and about 990 MMbbls of oil at surface condition.

10 Institutt for geologi og bergteknikk Hovedoppgaver 2008

Svendsen, Ole Magne S. (R.A. Kleiv)

Aspekter ved partikkelforurensning i borevæsker og optimalisering av Shale Shakere. Aspects of Particle Contamination in Drilling Fluid and Optimization of Shale Shaker Performance. Drilling fluid is charged with several critical tasks which is crucial to the success of a drilling operation. The properties of water base drilling fluid are sensitive to the influence of particles and therefore the removal of these is important to maintain the performance. The removal process is done mainly by shale shakers and this equipment is influenced by several internal and external factors. The optimization of shale shaker performance will lower drilling cost by improving drilling fluid life-expectancy, lessen consumption of screens and loss of fluid in shaker discharge. This thesis has through literature and experimental investigation addressed the influence of particles on the performance of water based drilling fluid. This has been done by looking into how particles influence the properties of water based drilling fluid and how this relates to performance. A special interest has been paid to rheology, clay mineralogy and colloid chemistry because of its large influence. A literary study of the factors influencing the performance of shale shakers and how it can be optimized has also been done. The work focused on the factors controlling both shaker and screen performance because of their dependency. An illustrative experimental investigation was conducted to highlight and support the influence of particle contamination of water base drilling fluid on viscosity and fluid retention. The investigation showed the influence of particle concentration, size, distribution and type on the fluid properties and showed support for the contention of 20 wt% as the limiting level for low gravity solids concentration. The study showed that influence of particle concentration, size and distribution has its greatest affect on density, rheological behaviour and filtration for water base drilling fluid. Clay and colloid material will have an increased affect due to their large surface area and high degree of electrostatic activity. Shale shaker performance is influenced by motion, g- factor, deck angle and fluid properties along with screen panel factors such as construction, material, maintenance and cut-point accuracy. The greatest optimization of shaker performance may be done by empirical configuration solutions of shaker and screen options, use of automatic shaker control and continuous particle monitoring and training of operating personnel to ensure proper maintenance.

Thoresen, Kristine (B. Nilsen)

Betydningen av hulldiameter og ingeniørgeologiske parametere for boring av injeksjonshull ved jernbanetunnel Lysaker – Sandvika. The significance of hole diameter and engineering geological parameters for grouthole drilling at railway tunnel Lysaker – Sandvika. Lysaker – Sandvika tunnelen er en del av dobbeltsporutbyggingen gjennom Asker og Bærum. Tunneltraséen går igjennom et tettbygd område og det stilles strenge krav til innlekkasje, kun 4 l/min/100 m tunnel er tillatt. Dette kan kun oppnås ved systematisk forinjeksjon, noe som innebærer at man på hele prosjektet vil komme opp i ca. 850.000 bormeter. Sandvik Tamrock AS har utviklet et borstålkonsept hvor man kan benytte 54 mm hulldiameter for injeksjonsboring, dette stålet benyttes av samtlige entreprenører på Lysaker – Sandvika prosjektet. Tidligere har det vært vanlig å benytte 64 mm hulldiameter for denne type boring. Ved bruk av 54 mm hulldiameter kan man forvente en høyere borsynk og dermed en reduksjon i den totale bortiden. Samme borstålet kan brukes for både salveboring og injeksjonsboring, man trenger bare bytte borkrone. Da man borer med en mindre diameter, medfører dette også mindre produksjon av borkaks, noe som gjør renseprosessen av tunnelvannet mindre omfattende. Teoretisk sett vil også pakkere som brukes under injeksjon sitte bedre i hullet. Parameterne borsynk og matertrykk er forsøkt korrelert mot de geologiske parameterne Q og RQD. Man fant her ikke noen signifikant sammenheng. Heller ikke mellom borsynk og inngått injeksjonsmasse fant man noen korrelasjon.

11 Institutt for geologi og bergteknikk Hovedoppgaver 2007

2007

Bjørklund, Hermod (C.C. Li)

Spenninger i berg og fjellsikring ved SILA-prosjektet i Narvik. Rock Stresses and Rock Support for SILA Project at Narvik.

Brenna, Asbjørn (M.B.E. Mørk)

En feltkarakteristikk av sprekkdannelse og tap av boreslam på Granefeltet. Field Characterization of Fracturing and Drilling Fluid loss Events on Grane.

Burås, Geir (M.B.E. Mørk)

Petrografi og diagenese av triassandstein, Kobbeformasjonen, Nordkappbassenget. Petrography and Diagenesis of Triassic Sandstones from the Kobbe Formation, Nordkapp Basin.

Cock, Christian Haug (S.O. Johnsen)

Forbedret avbildning av den dype geologien i Vøringbassenget ved bruk av bred-vinklet seismikk. Improved imaging of the deep Geology of Mid Norway Vøring Margin using wide-angle seismic data. Wide-angle seismic reflection data shot in 2004 and 2005 in the Norwegian Sea (MNR) provides a structural overview and high quality deep imaging of the Vøring Margin. Selected parts of the data shot in 2004 (MNR04) have been revived and improved by reprocessing it with focus on multiple attenuation. The available MNR data have been interpreted down to the Base Cretaceous unconformity which exceeds depths of 7 sec twt in the area. The interpretation verifies previously publicized interpretations.

Dew, Peter (K. Nielsen)

Naturressursforvaltning i et markedssamfunn. Natural resource management in a market orientated society.

Eggum, Anne I. Bjerke (E. Broch)

Romsåsen vegtunnel, felt- og laboratorieundersøkelser. Romsåsen road tunnel, field and laboratory investigations. Faget ingeniørgeologi har kommet frem i fokus etter noen uheldige hendelser i enkelte tunneler den siste tiden. Det kan nevnes raset i Hanekleivtunnelen i romjulen 2006 som ett eksempel. Dette har ført til at det ønskes økt omfang av ingeniørgeologisk oppfølging under driving på kommende tunnelprosjekt, i tillegg til utvidet etterkontrollering av eksisterende tunneler. Statens vegvesen region Øst bygger ny E18 fra kommunegrense Akershus til riksgrensen Sverige. Det innebærer blant annet en toløpet vegtunnel på parsell Krosby – Knapstad, Romsåsen vegtunnel. De to tunnelløpene deles omtrent på midten av en dagsone, hvor vegbanene her skal legges i kulvert. Det er gjennomført nye felt- og laboratorieundersøkelser på anlegget, og disse vurderes og sammenliknes med de eksisterende undersøkelsene og forholdene under driving. Feltundersøkelsene som er utført er bergartsbestemmelse, undersøkelse av sprekkeretninger og bestemmelse av bergmassekvalitet på enkelte blotninger. Prøvetaking til laboratorieundersøkelser av bergartsmateriale er gjort fra fjelltunnelene, samt sleppemateriale fra en sprekk i den nordvestlige tunnelen. Laboratorieundersøkelsene som er gjennomført på bergartsmaterialet er bestemmelse av mineralsammensetning, borbarhet, sprengbarhet og materialets evne til bruk i vegformål, og de undersøkelsene som inngår under dette. Undersøkelsene på sleppematerialet er utført for å få kjennskap til svellepotensialet i materialet. Resultatene fra feltundersøkelsene i åpnet anlegg tilsier at tunnelen bygges gjennom en glimmerrik gneis, hvor fjellkvaliteten er god. Det er lite problemer med innlekkasje av vann, og inndriften har vært godkjent. De seismiske undersøkelsene viser tre svakhetssoner i tillegg til dagsonen. Kun en av disse svakhetssonene bød på problemer ved passering, og krevde tyngre sikring enn resten av tunnelen. Resultatene fra laboratorieundersøkelsene viser en grovkornet bergart med god kvalitet med tanke på borbarhet og sprengbarhet, mens høyt glimmerinnhold fører til at sprengsteinen er uegnet i vegformål. Undersøkelsene av

12 Institutt for geologi og bergteknikk Hovedoppgaver 2007 sleppematerialet viser et innhold av svellende mineraler, som må holdes under nøye oppfølging under drift og etter åpning av anlegget. Etter litteratursøk i Statens vegvesens håndbøker og Miljø- og samfunnstjenlige tunneler om omfang av forundersøkelser, er det gjort funn som tilsier at kravene til kartlegging foran stuff under driving burde vært bedre spesifisert.

Eliassen, Tollef (T. Myran)

Overvåking av luftkvalitet og styring av ventilasjon i gruver. Monitoring of air quality and regulation of ventilation in mines. Hovedmålet med denne masteroppgaven har vært å presentere og samle kunnskapen de norske gruvene trenger for å møte de skjerpede kravene fra myndighetene, med særlig vekt på styring av ventilasjonen og detektering av NO2 i arbeidsatmosfæren. Den administrative normen for NO2 er redusert fra 2,0 ppm (T) til 0,6 ppm. Dette gjør at en økt innsats må til for å overholde myndighetenes krav.

Siden det i de fleste norske bergverk er NO2 som er den dimensjonerende faktoren, er det kun fokusert på denne gassen i masteroppgaven. Klarer man å holde NO2-konsentrasjonen under den administrative normen, har man også i de fleste tilfeller klart å overholde myndighetskravene til andre luftforurensinger som forekommer i en gruve. I tillegg til å samle og presentere kunnskap om lovverket, luftforurensinger og helseeffekter av disse, forurensningsbegrensende tiltak og ventilasjon er det utført ventilasjons- og luftkvalitetsmålinger ved Norcems gruve i

Brevik. Luftmengden er målt i hovedventilasjonen og i lokalventilasjonen og NO2-konsentrasjonene er målt ved de fleste arbeidsoperasjonene på flere ulike arbeidssteder. Dette gir informasjon om hvordan luftkvaliteten endrer seg ved ulik bruk av maskiner, tilført luftmengde og de generelle fysiske forhold på de ulike arbeidsstedene. I tillegg benyttes ventilasjonsmålingene for å se hvordan utbedringer av skader på dukene påvirker luftstrømmen og luftmengden ved utløpet. Der kjøretøy er benyttet er det anvendt to identiske NO2-målere. En av disse er montert på utsiden av kjøretøyet og den andre inne i førerhytten. Slik er det mulig å kartlegge rensingsgraden for hyttefiltrene.

Ventilasjonsmålingene viser at det i teorien tilføres frisk luft til gruva. Dette blir bekreftet av NO2-målingene, men siden operatørene i enkelte tilfeller eksponeres for NO2-konsentrasjoner over administrativ norm når ikke tilstrekkelige luftmengder arbeidsstedene i gruva. Ventilasjonsmålingene viser også at det har en positiv effekt å utbedre skader på ventilasjonsdukene. Målingene viser imidlertid at denne effekten ikke er så stor som først antat, og at skadene skal være omfattende før store forbedringer finner sted.

NO2-målingene viser at lasting og banking er de mest utsatte arbeidsoperasjonene. Særlig ved banking har man overeksponering for NO2. Dette skyldes utslippene fra motoren og at bankeren er stasjonær på stuff. I tillegg er rensingsgraden mellom førerhus og stuff ca. 20%, noe som er for lite til å overholde normen. Det bør derfor monteres aktivt kullfilter eller ved innkjøp av ny maskin sørge for at slikt filter er på plass. Ved alle arbeids-operasjoner som involverer kjøretøy anbefales det å kjøre med vinduer og dører igjen da dette senker NO2-konsentrasjonen i førerhuset med 20 – 40%. Ut ifra resultatene av ventilasjons- og gassmålingene viser det seg at dimensjoneringsreglene for ventilasjon er udaterte. Særlig dimensjoneringsmetoden som benytter effekt (kW) som parameter er for unøyaktig. Det bør derfor etableres nye dimensjoneringsmetoder for ventilasjon ved gruvedrift som benytter forbrukt diesel som parameter. Målingene i denne masteroppgaven bekrefter antagelsen om at måleapparatene med elektrokjemiske celler er for unøyaktige. Dette kan det til dels kompenseres for ved å kalibrere apparatene oftere enn anbefalt av produsent. Dette gjør apparatene egnet til gassalarmer. Ved arbeidsmiljøundersøkelser anbefales imidlertid å benytte mer nøyaktig utstyr, som diffusjonsprøvetagere.

Holsbrekken, Elisabeth (B. Nilsen)

Åknes skredområde – analyse av sammenheng mellom bevegelse og klima/nedbør (i samarbeid med ICG og Åknes/Tafjord-prosjektet). Åknes landslide area - correlation between displacement and climate/precipitation (in co-operation with ICG; International Centre of Geohazards, and the Åknes/Tafjord-project). Potential correlations between displacement and climate/precipitation for the Åknes rockslide area in western Norway have been analysed. The thesis work was included in a comprehensive research programme on rock slope stability, and also represents a follow-up of project work carried out by this student in the fall semester 2006, focusing on collecting engineering geological background data and reviewing previously published correlations between displacement and

13 Institutt for geologi og bergteknikk Hovedoppgaver 2007 climate/precipitation for large rock slides. In the thesis work, most of the effort has been spent on reviewing and systemizing available climatic and precipitation data for climatic stations close to Åknes and results from extensometer measurements at the back scarp. Interesting correlations between displacements and precipitation/temperature have been established, but in some cases considerable uncertainty in correlation is caused by insufficient data or lack of relevant data.

Johansen, Lene K. (T. Myran)

Utslipp av luft fra aminprosessen i et fangstanlegg for CO2 – Ytre miljøkonsekvenser.

Emissions to air from the amine process in a capture plant for CO2 - Environmental consequences.

CO2 er den største kilden til de menneskeskapte klimagassene og viktigste bidragsyter til den globale drivhuseffekten, og er i dag et problem som er ønskelig å gjøre noe med [Stortingsmelding nr. 9]. I 2005 lanserte Aker Kværner og

GassNova et samarbeid om ny teknologi for CO2-fangst. Anlegget vil være omtrent ti ganger større enn det største fangstanlegget som eksisterer i dag [Christensen, 2006]. I forbindelse med dette er Aker Kværner interessert i å vite om aminet MonoEtanolAmin (MEA) som brukes i renseprosessen ved CO2-fangst har noen effekt på det ytre miljø når de slippes ut til luft.

Oppgavens problemstilling omhandler CO2-fangst ved eksosforbrenning fra gasskraftanlegg, og skal gi en oversikt over hvilke ytre miljømessige effekter som kan oppstå når aminet MEA og dets degraderingskomponenter, som hovedsakelig er ammoniakk, slippes ut til luft fra absorberen under aminprosessen. I tillegg skal oppgaven, om mulig, gi et forslag til relevante verdier som kan brukes for å fastsette utslippsgrenser i forbindelse med MEA-utslipp til luft fra gasskraft- og fangstanlegg. Det kommer fram i litteraturen at aminer har liknende oppbygning som ammoniakk og dermed er det mulig å anta at de også kan ha samme egenskaper som ammoniakk. Det vil si at det er muligheter for at de kan være med å bidra til forsuring og gi avrenning av nitrater til vassdrag. Når det gjelder ammoniakkutslipp, er dette en kilde til stor bekymring når det gjelder luftkvalitet regionalt og nasjonalt i Amerika, samt globalt [Gay, Knowlton, 2005]. Nedfall av ammoniakk som er sluppet ut til luft kan føre til flere negative effekter. I overflatevann kan nedfall føre til økt algevekst, redusert tilgang til oksygen for dyr og andre planter som lever i vannet og dermed fiske- og plantedød. I tillegg kan dyrkede frukter og grønnsaker som tomater og slangeagurker, samt nåletrær bli skadet ved overgjødsling grunnet ammoniakk hvis de befinner seg i området rundt ammoniakkilden [van der Eerden et al., 1998. Gjengitt i Gay, Knowlton,

2005]. Ammoniakk bidrar også til å forsure jordsmonnet ved at ammoniakk oksiderer til NO3 direkte eller tas opp i jord og + planter. Et ionebytte tar plass og på denne måten dannes H -ioner som gjør jorden sur [Miljøstatus, 2007c] . Det har ikke vært mulig å komme med forslag til grenseverdier for utslipp av MEA fra fangstanlegg. Årsaken er at det ennu ikke er forsket på hvilke effekter MEA vil ha både når det gjelder spredning og virkning på resipienter når MEA slippes ut fra pipa i fangstanlegget. Det finnes imidlertid HMS-datablader som fastsetter normverdier i forbindelse med arbeidsmiljø. Disse verdiene går på direkte kontakt med ren, konsentrert MEA, og det antas at de samme effektene ikke vil oppstå ved utslipp til luft fra fangstanlegg, da det ikke lengre er snakk om at de samme mengdene vil nå eventuelle resipienter. Dermed vil normverdiene kun, om mulig, gi en liten pekepinn på effekter MEA kan føre til ved utslipp til luft. De framstillingene i rapporten som er gjort av MEA er kun antagelser. Det er dermed vanskelig å komme med noen konkret og 100% sannsynlig påstand om hva som kreves for å forhindre negative miljøeffekter. For å oppnå dette, anbefales det at det utføres tester på både planter og dyr med reelle konsentrasjoner av MEA over lengre perioder. Langvarige tester og forskning på utslipp av MEA til luft fra fangstanlegg er muligens den eneste måten å erverve resultater som er nøyaktige nok til å bekrefte eller avkrefte teoriene om MEA, samt konsekvenser et utslipp av MEA vil få.

Kalstø, Trond K. (S. Lippard)

Sen kritt/paleocen oppløftning av Utsirahøyden avgrenset ved hjelp av seismisk tolkning og sekvensstratigrafi. The Late Cretaceous-Paleocene exhumation of the Utsira High constrained by seismic/sequence stratigraphy. The Upper Cretaceous – Early Paleocene Shetland Group chalk facies in blocks 16/2 and 16/3 on the Utsira High are examined using a semi-regional sequence stratigraphic 3D analysis. Using seismic 3D and 2D data in addition to well logs the Hod formation is subdivided into the Magne and Thud formations. Two important sequence boundaries resulting from tectonic uplift combined with eustatic sea level fall are recognized, Top Magne (Campanian) and Top Tor (latest maastrichtian). The Campanian event is ascribed to transpressional stress along the Sorgenfrei-Tornquist Zone, while the Late Maastrichtian – Early Danian event is of a different character and possibly related to tectonic relaxation de to influence of the Iceland Plume. A large canyon structure occurs within blocks 16/2 and 16/3, inferred to the result of submarine current erosion during Late Cretaceous - Early Paleocene, later to be infilled with Paleocene sediments.

14 Institutt for geologi og bergteknikk Hovedoppgaver 2007

Influence of strong bottom currents during chalk deposition stands in marked contrast to the conventional picture of quiet pelagic deposition of the chalk. The possibility of subaerial exposure of the chalk on the Utsira High in the latest Cretaceous is examined by analysing cores from the top chalk interval in wells 25/11-16 and 25/11-17. No evidence of karst topography is seen on seismic data, but local subaerial exposure and karst development is suggested based on well data. Numerous slide scars are interpreted on the top chalk surface as well as a turbidite mass flow resulting from an unstable chalk slope, spossibly induced by flexural uplift in latest Maastrichtian. Isopach maps for Cretaceous – Lower Paleocene sediments show that the chalk depositional pattern changed during this time due to influence of tectonic uplift and infilling of earlier relief. Paleogeographic maps for earliest Cenomanian and latest Danian are reconstructed using seismic data flattened on Top Balder surface. The most important implication for future hydrocarbon exploration is that the Late Cretaceous sea floor topography was of considerable relief and that stratigraphy traps may have been created during Paleocene infilling of this topography.

Khan, Shagufta Naz (T. Myran)

Steinmaterialets betydning for finstoffproduksjon. The Significance of Rock Material for Products of Fines. Oppgaven inngår som en del av et prosjekt ved Statens Vegvesen, Vegdirektoratet, der målet er å finne og bruke de steinmaterialene i vegen som skaper minst støv og støy. Støvet som dannes ved piggdekkslitasje av vegdekket kan medføre problemer og skape helsefare. Analyse av prøver fra ulike typer steinmaterialer har blitt utført for å få en indikasjon på hvilke materialer som skaper mest støv og størst helsefare. Prøvene ble tatt fra 6 steinmaterialer som kom fra 6 ulike pukkverk: gabbro fra Vassfjell, mylonitt fra Ottersbo, hornfels fra Lierskogen, mylonitt (durasplitt) fra Tau, kvartsitt fra Kråkmo, kvartsitt fra Dalbo. Prøvene ble analysert for andel vekt i støv mindre enn 0,063 mm og andel vekt i støv større enn 0,063 mm. Det ble påvist at vekten til støv mindre enn 0,063 mm er høyere, noe som kan tyde på at når piggdekk sliter vegdekket, dannes partikler i de minste fraksjonene. Prøvene gjennomgikk densitets- og kulemølletesten, hvor materialet ble siktet både før og etter kulemøllen. Steinmaterialet gikk ikke gjennom en vanlig kulemøllemetode, men det ble utført en modifisert utgave av metoden. Veieskjemaet til 3 ulike asfalttyper, Ska11, Ab11 og Da11, ble fulgt for å sette sammen prøvene som ble kjørt i kulemøllen. Analysene viste at det ble dannet mye finstoff (kornstørrelse < 0,063 mm) for alle 3 asfaltdekker, hvor Ab11 skilte seg litt ut ved å produsere mest støv. Det ble også utført en mineralogisk vurdering av steinmaterialene for å finne de prøvene som kan skape mest potensielt helseskadelig (giftig) støv. Prøvene som nådde høyest på den relative giftighetsskalaen kom fra de sterkeste steinmaterialene. Vurderingene viste at de prøvene som hadde høyest andel innhold av kvarts, var de prøvene som endte på den øverste delen av giftighetstabellen. Resultatene indikerer at hvilken type steinmateriale som blir brukt har mye å si for hvor mye støv/finstoff som blir produsert og hvor farlig dette støvet/finstoffet er. De viser også at variasjonen og usikkerheten er stor. Det kreves mer omfattende undersøkelser for å kunne komme med anbefalinger og trekke klare slutninger.

Kjesbu, Kristian (C.C. Li)

Sigunit sprøytebetongakselerator til fjellsikring. Sigunit shotcrete accelerator for construction in rock. The goal with this project was to look closer on the Sigunit´s properties related to use in water filled areas in rock. This accelerator is known for giving a high early strength, but sadly also for having some problems related to water in rock in underground projects. A project based on this was started between the companies Sika Norge AS, AF anlegget and the university NTNU. Testing of different accelerators for shotcrete, which differences these had and how they tackled water filled rock have been the focus for this work. The methods used in the project involved determination of early – strength by use of penetration needle and Hilti pistol, close follow–up of the spaying process and important factors here, measurements of temperature development and literature studies. The maturity – principia have been used for comparing the different accelerators. Calibrations of equipment have been performed in laboratory. The 2 chosen building projects for colleting data was Leirfossen project in Trondheim and Saudafaldene project in Sauda. Sadly, both were relatively dry under the testing periods, so the problems with water have not been much tested. According to strength development, number of downfalls, and the little water that was found, it looks like Sigunit Type 3 is the best choice for use in water filled rock in rock construction.

15 Institutt for geologi og bergteknikk Hovedoppgaver 2007

Lindhjem, Rune (C.C. Li)

Økonomiske fordeler ved bruk av Devico-metoden for “Sidetracking” og retningsstyrt kjerneboring i malmprospektering. Economical benefit by use of the Devico method for sidetracking and directional core drilling in deep hole exploration. The purpose of this thesis is to show the economical benefit in the use of the Devico method within ore prospecting. The first part includes a comparison of the Devico method with different directional methods and conventional core drilling from the surface. Advantages and disadvantages with the various methods are listed and later discussed. It is described how the Devico method has great benefits in simplicity, efficiency and accuracy. Thereafter most focus is put on the Devico method versus conventional drilling from the surface. This is first done in a theoretical manner where a simple calculation method based on penetration rate and target position is used to illustrate the saving tendencies in various situations. The main parameters that affect the economical picture are discussed and presented mathematically. The results only show the effect under near ideal conditions with favorable geology and no logistical or technical problems. Under these conditions it seems obvious that the depth and the distance to the target greatly affect the savings, while the leasing fee of the Devico system gives clear limitations in the achieved results. After that, it is discussed how the economical situation often is influenced by factors and limitations related to geology, operation, technology, etc. These are some of the reasons why the mathematically optimal solutions are rarely as accurate and optimal as expected. The discussion is limited to the parameters related to directional drilling with the Devico system. The section that finalizes this thesis includes actual data from a few Devico projects which is analyzed to demonstrate the real economical benefit and optimal solutions. The results show that cost savings of up to 80% can occur, while time savings of 50-60% are common.

Lorentsen, Bjørn S. (S.O. Johnsen)

Reservoarmodellering ved hjelp av SBEDStudio. Reservoir modelling using SBEDStudio. A good reservoir model is of great importance for the recovery from an oil field. The problems related to reservoir modelling are caused by de limited amount of available data. SBED is a program that take depositional processes into consideration and that also include small scale structures even during upscaling. In this thesis the parameters in SBED models of point bars have been upscaled and put into SBEDStudio models. On these models the program RocDoc has been used to produce synthetic seismic. The results show that there are hardly any differences in the parameters in the upscaled models and it is not possible to observe any differences on the seismic. This is because the SBED cores are in cm-scale and the seismic in m-scale. However, it is possible to observe the mud filled channels on the seismic.

Mekonnen, Kassahun D. (B. Nilsen)

Rock slope stability analyses for Tekeze hydropower project, Ethiopia. This thesis is discussing engineering geological challenges for hydropower projects with particular emphasis on potential problems related to the rock slope stability of dam site and reservoir areas. As introduction, relevant cases concerning stability problems related to reservoir areas and dam sites for hydropower projects are described and discussed on a general basis. As special case for the study, the Tekeze Hydropower project in Ethiopia is analysed. Tekeze is a 300 MW project at an early stage of construction with a 188 m high arch dam, rock tunnels and an underground powerhouse cavern. Feasibility- and more detailed study for the project, including core drilling, laboratory testing of rocks etc. have been done by Harza. The thesis work has been focusing on the engineering geological aspects of the project, with main emphasis on dam site and reservoir slope stability based on review of literature and relevant reports, identification of critical areas based on stereographic projection techniques and stability analysis of critical areas. Relevant computer software; i.e. Dips and SLIDE, was used for the stability analysis. It has been found that the rock slopes that have been analysed are fairly stable. A considerable degree of uncertainty is however connected to the input-parameters, and further investigations are recommended in order to improve the reliability.

Mosnesset, Ina N. (E. Broch)

Vann- og frostsikringshvelv i norske vegtunneler. Inner linings in Norwegian road tunnels.

16 Institutt for geologi og bergteknikk Hovedoppgaver 2007

En rekke systemer for vann- og frostsikring har opp gjennom årene blitt testet og tatt i bruk i norske vegtunneler. Per dags dato er det kun et fåtall av disse som er typegodkjente av Vegdirektoratet, og denne rapporten gir en kort innføring i hvilke løsninger som er tilgjengelige på dagens marked. Et utvalg vann- og frostsikringskonstruksjoner deriblant PE- skum, en løsning kalt WaPro-vannavskjermingssystem som er på veg inn på markedet, og løsninger med prefabrikkerte betongelementer både i vegger og tak og en Giertsendukløsning er valgt ut og blir presentert. Herunder kommer fordeler og ulemper, samt erfaringer gjort av entreprenør som har tatt i bruk disse metodene. I tillegg er det gjort vurderinger rundt hvordan hver av vann- og frostsikringsløsningene legger til rette for inspeksjoner og etterkontroll bak hvelvene. Hovedfokus vil ligge på konstruksjonen med betongelementer både i vegger og tak som monteres i Ny Kleivene tunnel på E18 sør for Drammen, og de utfordringene entreprenøren Mesta har støtt på der i forbindelse med et svært trangt sikringsrom for montering av vann- og frostsikringshvelvet. I tillegg vil et av hovedtemaene i denne rapporten være aktuelle regelverk, krav, forskrifter og retningslinjer som finnes når det gjelder vann- og frostsikring og inspiserbarhet bak hvelv i tunneler. Det vil i den sammenheng særlig rettes et kritisk blikk mot Håndbok nr. 163 Vann- og frostsikring i vegtunneler. Etter som det hele tiden kommer nye vann- og frostsikringskonstruksjoner på markedet og kravene til for eksempel sikkerhet og estetikk i tunneler endrer seg både internasjonalt og innad i Norge, arbeider Vegdirektoratet hele tiden med å revidere og oppdatere kravene og forskriftene som finnes. Og særlig nå i etterkant av raset som gikk i Hanekleivtunnelen 1. juledag 2006, er det satt ytterligere fokus på om regelverket er godt nok. Både Samferdsels-departementet, Vegdirektoratet og bransjen generelt er på banen i diskusjonen som har fulgt hendelsen i Hanekleivtunnelen, og et representativt utvalg av denne debatten presenteres og kommenteres i denne rapporten. I denne delen av oppgaven vil også Hanekleivrapporten, som ble utarbeidet av en utnevnt undersøkelsesgruppe i etterkant av raset 1. juledag 2006, stå sentralt. Et gjennomgående hovedfokus i denne oppgaven vil som nevnt tidligere være inspiserbarhet og etterkontroll av stabilitet i vegtunneler. Ved å studere regelverket, se på et representativt utvalg av aktuelle vann- og frostsikringskonstruksjoner på markedet og å skaffe et overblikk over bransjens tanker rundt temaet, viser det seg at det ikke skal store endringer til på selve vann- og frostsikringshvelvene for å muliggjøre etterkontroll bak hvelvene i fremtiden. Utfordringen ligger i å utforme et regelverk som er spesifikt nok og behandler dette med inspeksjonsmuligheter bak hvelv på en bedre måte enn det gjøres i dag, og det må bevilges nok penger til at det blir mulig å installere det nødvendige klatre- og sikkerhetsutstyret i tunnelene. Og ikke minst må det gås inn for å drive tunnelene med et større sikringsrom enn det som er vanlig i dag, dersom det i det hele tatt skal bli mulig å komme bak vann- og frostsikringshvelvene under en inspeksjon.

Nesje, Linda (B. Nilsen)

Rogfast-tunnelen – Analyse av nøyaktigheita av geofysikk for kartlegging av svakheitssoner (i samarbeid med Statens vegvesen vest). Rogfast subsea tunnel - analyses of the usefulness of geophysical investigations for mapping of weakness zones (in co- operation with Statens vegvesen vest). As a follow up of introductory analysis in project work (fall 2006), the reliability of geophysical investigations for mapping faults/weakness zones has been analysed in detail. Main focus has been on projects in the Boknfjord area, with the planned Rogfast tunnel as main object for study. For the 24 km long Rogfast subsea tunnel, presently under planning by the Norwegian Public Road Authorities, comprehensive seismic investigations have been carried out by Geomap, and magnetometry, lineament studies etc. by NGU. Comprehensive investigations also have been carried out for several nearby projects, of which some have been constructed, thus making possible comparison between prognosis and reality. Main emphasis has been placed on: 1) Previous experience of such correlation based on literature review, 2) Extensive analysis of correlation between geophysical parameters and as-built conditions for selected subsea tunnels in the Boknfjord-area, Finnfast, Ryfast, IVAR, Karmøy-Kårstø and T-forbindelsen, and 3) Evaluation of probable faults/weakness zones along Rogfast. The main conclusion is that refraction seismics gives the best correlation (up to 50-67%), while magnetometry and lineament studies give poorer correlation (33% and 16%, respectively).

Pathak, Surendra Raj (B. Nilsen)

Engineering geological analyses for Upper Hewa Khola hydropower project, Nepal The thesis work is focusing on engineering geological challenges for hydropower projects in Himalayan rock conditions. As introduction, the rock engineering problems that may occur during construction and operation of such projects, with main emphasis on underground excavations, are discussed. Relevant cases from Himalayan conditions are also described and discussed. As special case for the study, the planned Upper Hewa Khola Hydropower project in the eastern region of Nepal has been analysed. Upper Hewa is a 10 MW run-of river project which is planned with a 2870 m long headrace tunnel and a surface powerhouse. Feasibility study for the project, including core drilling, laboratory

17 Institutt for geologi og bergteknikk Hovedoppgaver 2007 testing of rocks, etc. has been done by NEA (Nepal Electricity Authority). The bedrock in the project area consists of quartzite, phyllite and intercalations of those two rock types. Main emphasis in the thesis is placed on the engineering geological aspects of the project, with main emphasis on the following issues (in order of priority): 1) Stability and support requirement of the headrace tunnel, 2) Slope stability of the tunnel entrance- and powerhouse pit areas, and 3) Alternative option of locating the powerhouse underground. Relevant computer software; i.e. Phase2 and/or SLIDE, have been used for stability analysis. Supplementary field work is recommended for improving the reliability of input parameters for calculations and analyses.

Shirinov, Ramin (M.B.E. Mørk)

Diagenetic study of the Åre Formation, Norwegian Sea.

Shrestha, Prabhat M. (B. Nilsen)

Engineering geological analyses for Seti Trisuli hydropower development, Nepal. This MSc-thesis is focusing engineering geological challenges for hydropower projects in Himalayan rock conditions. As introduction, the rock engineering problems that may occur during construction and operation of such projects, with main emphasis on rock slope stability, are discussed. Relevant cases from Himalayan conditions are also described and discussed. As special case for the study, the planned Seti Trisuli River Hydropower Development in Nepal has been analysed. This project is planned with a 80 m high rock fill dam, an approximately 800 m long headrace tunnel, 4 diversion tunnels and a surface powerhouse as the most likely option. The project area belongs to the meta-sedimentary unit of lesser Himalaya, with phyllite as the predominant rock type. Feasibility study for the project, including core drilling, laboratory testing of rocks, etc. have been done by NEA (Nepal Electricity Authority). The thesis is focusing mainly on the engineering geological aspects of the project, with main emphasis on (in order of priority): 1) Slope stability of the dam site and reservoir areas, 2) Stability and support requirement of the tunnels and 3) Alternative option of locating the powerhouse underground. The use of relevant computer software; i.e. Phase2, has been included in stability analysis. Based on the analyses, recommendations have been made for rock support, further geological investigations and monitoring during construction.

Shukla, Ashwini Kumar (E. Broch)

Engineering Geological Evaluation of a Hydropower Project in India. Lohari Nag Pala H.E. project (4 x 150 MW), located in Indian Himalaya, consist of underground water conveyance system as well as powerhouse. The main rock types in the area are various kinds of gneisses with the bands of metabasics and quartz veins. The objective of the thesis work was to carry out engineering geological evaluation of the project in the light of Norwegian design practices. Four different alignments of the head race tunnel were studied and the best one with the provision of surge shaft was selected for the further study. Further, four alternatives of the water conveyance system (head race tunnel, surge shafts, pressure shaft, penstock and tail race tunnel) i.e. fully concrete lined, single unlined, fully shotcreted and two parallel unlined tunnels (horse shoe shaped, drill and blast tunnel) were studied. The rock support was designed with the help of Q system. Time prognosis for the head race tunnel indicated that one adit would be enough for the timely completion of the project. The rock stress situation was evaluated in the tunnels system and powerhouse with the help of empirical methods and was found that there would not be any stress induced problem. However, vulnerable locations in the head race tunnel were identified with the help of Norwegian experience. The orientation of the long axis of the powerhouse and the internal arrangement was evaluated according to the Norwegian principles and was found in agreement. At last, the cost prognosis based upon Indian rates as well as Norwegian rates was made for the alternatives of the HRT to find the most viable solution. The shotcreted tunnel was found as the cheapest followed by the unlined and concrete lined with a small cost difference. It was found that the concrete lined tunnel in India is 4.8% more costly than the unlined while in Norway concrete lined tunnel will cost just double of the unlined tunnel. It was found that ratio between “cost of excavation” per m3 and “cost of concrete lining” per m3 in Norway is approximately 1:16, while the same in India is merely 1:2.4. Since, the concrete lining in Norway is very costly as compared to the cost of excavation, unlined tunnel fetches substantial saving. While in the India, the same ratio is quite low hence, in the unlined tunnels the saving made on the concrete lining is neutralized by the cost of excavation. So, the concrete lined tunnels become more suitable. Similarly, the cost prognosis was prepared for all the alternatives of the pressure shaft, penstock and tailrace tunnel. It was found that steel lined pressure shaft was three times costlier than the concrete lined or unlined pressure shaft.

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Hence, it is recommended to provide concrete lined pressure shaft instead of steel lined. Final cost prognosis for the different alternatives of the water conveyance system was made by putting all the pieces together. It was found that the unlined water conveyance system in India costs almost equally as the concrete lined alternative. But the concrete lined tunnels offer greater safety and moreover instill a greater degree of confidence in the lenders, investors and developers. Hence, it becomes the natural choice.

Stenerud, Jørgen (C.C. Li)

Skråningsstabilitet i dagbrudd på Stjernøy, Nord-Norge. Open pit mine slope stability on Stjernøy, Northern Norway. Computer based probabilistic and deterministic analysis of slope stability has been performed with software from RocScience, using the Barton-Bandis shear failure criterion. Initial fieldwork was carried out in the existing mine tunnels in close proximity to the future pit mine, and consisted of mapping joints and measuring shear parameters joint roughness, friction angle and joint wall compressive strength. The stability is expected to be determined by joint spacing, orientation and shear strength. Stereographic projection shows two main joint directions with unfavourable orientation in respect to the pit mine. The possibility of sliding along one joint plane will be significant in some areas of the mine, and reducing the slope angle will have a positive effect. The high joint spacing however makes it difficult to predict the possibility of slides occurring. The probability of wedge slides is relatively low, but local reinforcement with bolts or cables could be necessary as the slope angle is shown not to affect wedge stability. Occurrence of large scale slides is considered improbable.

Sviland, Anita (S. Lippard)

Irap RMS Facies modellering av den jurassiske Pelion-formasjonen ved Lias elv, Øst-Grønland. Irap RMS Facies Modelling of the Jurassic Pelion Formation at Lias Elv, East Greenland. The idea behind the work documented in this thesis was to refine a crude geo-model of shallow marine sandstone units in the Pelion Formation that was finished in December 2006. The work includes structural modelling and facies modelling, and thus covers the first two steps of the Reservoir Modelling Workflow in Irap RMS. The Pelion Formation is considered an analogue to the Garn Formation at Haltenbanken on the Norwegian Continental Shelf (NOCS). The fact that this model is based on an outcrop analogue and not on a subsurface reservoir makes it interesting, but also challenging. The model is built using sedimentological logs, logged by Statoil representatives in the period 2004-2006, instead of well logs. GPS data collected from Greenland together with nine different logs constituted the basis for the coordinate system and the surface model. LIDAR data was used for visualisation in the area in addition to serve as a terrain model in RMS. LIDAR technology is able to give field geologists both image data and positional accuracy and the technologh is believed to improve field work where used. In this thesis it was not realistic (due to the late arrival of the LIDAR data and the time frame) to fully incorporate this data into the modelling workflow. Trend maps were constructed in RMS based on base maps (interpretation of the facies distribution in the different sequences). Trend maps were necessary to implement some of the geological observations and concepts into the model. Three facies models of the Pelion Formation in East Greenland were made with different degrees of complexity. The simple model was only constrained by well data. Well data was in this thesis the only “hard data” available. The simple model was made to give an example of the information available in most real cases, where the model often has only well data and seismic data to rely on. The second model constructed was constrained by both well data and vertical proportion curves. Vertical proportion curves were obtained from RMS and show the vertical distribution of facies in the formation based on the well information. Thus, this model is also vertically constrained. The final and most advanced model has, in addition to the input used in the two other models, three trend maps embodied for lateral facies control. The trend maps are based on ideas and interpretation done by Statoil and thus represent what is called “soft data”. This model is considered the model closest to the Pelion Formation during the Mid Jurassic.

Tjetland, Gøril (S. Lippard)

Kvalitetskriterier til den blottlagte Sen Kritt – Tidlig Paleosene Finnmark Platform Øst. Characteristics of the Late Cretaceous – Paleocene denudation of the Finnmark Platform East area.

19 Institutt for geologi og bergteknikk Hovedoppgaver 2007

The most prominent Upper Cretaceous seismic reflectors are interpreted in the southeasthern Barents Sea. A restricted core area comprising the northwestern part of the Finnmark Platform East, the southern Nordkapp Basin and the Nysleppen Segment is especially investigated. The prominent Base tertiary reflector provides evidence of a denudated Late Cretaceous platform in the eastern Finnmark Platform area and on the Nysleppen Segment. Seismic sections and mapped structure contour maps of the Base Tertiary reflector show concave down and concave up structures that link in large (km x km) longitudinal drainage systems and highs/ridges on which large collapse structures have developed in places. The drainage systems trend NE-SW and NW-SE and preferably developed on positive high(s) on the Finnmark Platform East. Most of the Upper Cretaceous sequence is removed during Quaternary erosions and Late Cretaceous – Early Paleocene erosive features are only preserved along the c. 20 km wide transition between the southern Nordkapp Basin and the Finnmark Platform East. Two major incisions (generally 1.3 – 2 km wide and > 40 km long) trend NW and ENE and have a sharp erosive cliff character along the southern border. Adjacent channelized systems are interpreted with more uncertainty due to wide seismic line spacing. An undulating Base Tertiary reflector is also observed at two smaller locations in the Hammerfest Basin; in blocks 7122/7 and 7122/4. Here the concave down and concave up structures might be both erosion and/or deposition related. In the westernmost part of the study area Danian claystones lie conformable on Maastrichtian mudstones. Combined seismic mapping and interpretation together with stratigraphic studies suggest that the channelized features and bulges observed on seismic images as downcutting seismic reflectors, are a product of erosive events in the Late Cretaceous – Danian period. Based on seismic interpretation at least two main erosional events are distinguished, one by the prominent Base Tertiary reflector and the other by an internal Upper Cretaceous reflector. The first event is suggested to have occurred in the Early Campanian(?) and the last in Danian. Whether the Late Cretaceous platform(s) was subaerial exposed is a matter of discussion, but more than 200 meters of sediments are removed in parts of the study area. In deeper areas submarine erosion by i.e. bottom currents is present, but the undulalting surface observed on the Finnmark Platform East has a more subaerial character in that a significant sediment pile (c. 150 m) is removed in channelized features and angular collapse structures are observed.

Ulla, Kristian M. (B. Brattli)

Oppfølgende undersøkelser av forurenset lokalitet ved Skoddebergvatn, Troms fylke. Following up Investigations of a Polluted Locality of Skoddebergvatn, Troms county.

Vatle, Anders (E. Broch)

Driftserfaringer fra underjordiske lagerhaller. Experience from the operation of underground storage caverns. This thesis discusses the experience from operation of underground storage of oil and gas in unlined rock caverns in Norway. In the first part general aspects like geological pre-investigations, decisions about location and the shape and size of the caverns are discussed. In the second part selected caverns for storage of different oil products and gas are described, and the experience from both the construction phase as well as the operation stage are discussed.

Vingerhagen, Gjermund (K. Rokoengen)

Nidelvdeltaets utvikling med vekt på stratigrafi og skred. Processes in the Nidelv delta, Trondheim, Norway, with emphasis on slides and stratigraphy. The Nidelv delta is located at the river outlet of Nidelva in Trondheim, Mid-Norway. During the last 12.400 – 12.800 years BP the sea level has dropped by approximately 175 meters (575 feet) due to isostasy in this area. The Nidelva river has eroded through marine sediments and glacial deposits from the last glacial period, and transported the sediments to the delta front. In 1888, 1950 and 1990 three sunbmarine slides in the delta damaged construction sites at land. The geomorphology in the submarine parts of the Nidelv delta is divided in two. The eastern part of the delta is characterized by a gently dipping slope towards the deeper part of the fjord in north-east. The river outlet of Nidelva is influencing this part of the delta. The western part of the delta is characterized by steeper ground. A main structure is a submarine channel. This starts close to land and cuts through sediments out to the central fjord. Three main types of investigation methods have been used in this report; high-resolution bathymetry, high-resolution seismic and gravity core samples. Additionally a ROV with camera has been used and marine fossils have been dated.

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The bathymetry results from the western part of the delta show evidences of many slides. The biggest, the W-slide, is 420 meters (1377 feet) wide and 150 meter (492 feet) long. Most of the slides are located in the slopes down to the submarine channel. The slide scarps varies in form, from fresh to well-rounded. The W-slide scarps are still quite fresh. There have been interpreted three different seismic layers. Glacimarine/marine sediments, delta slope sediments and slide influenced sediments. Delta slope and slide influenced sediments are dominating close to land. In the distal part of the delta are glacimarine/marine sediments dominating. Dated fossils in the sediments give sedimentation rates from 0,3 - 5 mm/year. The highest sedimentation rates are found in the eastern part of the delta, closest to the river outlet. The sedimentation rates in the central part of the fjord are higher than in the western part of the delta. Estimating the ages of light grey clay layers found in core samples gives an overweight of ages around 1900 ± 100 years BP. These layers can be deposits from landslides along the Nidelva River.

Østre, Stig Kjellesvik (S. Lippard)

Integrert tolkning av seismiske data og brønndata i utviklingen av en oppdatert geologisk modell for X-segment på Heidrun East Flank. Integrated Interpretation of Seismic Data and Well Data in the Development of an Updated Structural Geologic Model for the X-segment on the Heidrun East Flank. The Heidrun field off the coast of Mid-Norway is an oil and gas field that has been on stream since 1995. At a mature stage in an oilfield‟s lifespan it becomes critical to discover new reserves and to develop these. These reserves are often characterized by small volumes and are frequently situated in complex structures. Within the recent years, several compartments of the Heidrun Field have been and are being developed in order to mature new reserves from proven resources. One of these areas is the X-segment on the Heidrun East Flank. This segment is a hanging wall fault block, down-faulted relative to the Heidrun main field and is divided into two main structures; X_south and X_ north. The area shows varying degree of complexity, where the northern structure has proven to be the most complex part. Previous development of the Heidrun X-segment includes the generation of an integrated segment reservoir model. Seismic data and wells from other parts of the field were utilized in this work. The goal was to create a functional segment model to use in well planning, volumetric calculations and production prognosis. The poor quality of the seismic data in the X-segment and the lack of X-segment wells made this work challenging. The wells drilled in the X-segment proved that the segment had not been fully understood when the initial model was made. In an attempt to explain some of the observations done in the wells, a new scenario for the structural development of the X-segment was introduced. This suggested that the segment was the combined result of late Jurassic extensional faulting and late Cretaceous unconstrained gravitational collapse. This gravitational collapse was believed to be induced by migration of Triassic salt deposits beneath the Grinda Graben. As a part of this diploma thesis a complete seismic re-interpretation of the x-segment was carried out. The goal for this work has been to integrate seismic interpretation with well and production data that have become available after the first detailed interpretation of the X-segment was carried out. Integration of several types of data will reduce uncertainties associated with the seismic and geologic interpretation. The results of this re-interpretation led to a new proposal for the structural development of the X-segment and this has been compared with the previous interpretation/scenarios.

Aardal, Ingrid Buvarp (B. Nilsen)

Åknes skredområde – analyse av korrelasjonar mellom borehullsgeofysikk og bruddfrekvens frå kjernelogging (i samarbeid med NGU/IGC). Åknes landslide area – analysis of correlation between borehole geophysical data and fracture frequency from core logging (in co-operation with NGU/IGC). Correlations between borehole geophysical data and fracture frequency have been analysed for the Åknes rockslide area in western Norway. The thesis is included in a comprehensive research programme on rock slope stability, and also represents a follow-up of project work carried out by this student during the fall semester 2006, including extensive field work, literature review and review of geophysical data for Åknes. One core-drillhole from each of 3 main locations in the Åknes landslide area is included in the study, and as assumed reference for stable rock, one drillhole from the Lunner road tunnel project is also included. In the thesis, main emphasis is placed on analysing 1) Mutual correlations between main geophysical parameters (P- and S-velocity and resistivity), 2) Correlations between the main geophysical parameters and fracture frequency based on core drilling, and 3) Correlations between secondary parameters (Poisson‟s ratio, porosity, semblance) and fracture frequency. Correlation analyses between main geophysical parameters (seismic

21 Institutt for geologi og bergteknikk Hovedoppgaver 2007 velocities, resistivity, semblance) and fracture parameters have been found to show obvious trends, but also emphasize that the velocity range is wide. Poisson‟s ratio has been found to represent a poor rock quality indicator for Åknes.

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2006

Aktar, Mosammat N. (M.B.E. Mørk)

Petrography and Diagenesis of Sandstones from the Stø Formation, Western Barents Sea.

Akter, Salma (M.B.E. Mørk)

Petrography and Diagenesis of Sandstones from the Furuholmen Formation, Nordkapp Basin, Barents sea.

Bremnes, Kari (E. Broch)

Factors influencing the choice of excavation method for urban tunnels excavated in rock mass. This thesis analyses the factors influencing the choice of excavation method when tunnelling in urban areas in a rock mass. There are several factors influencing this choice such as environmental factors, construction time, geological and geomechanical factors along with the total cost of the project and many more. The most important factors has been analysed in this thesis. A specific example from the Martignano tunnel in Italy is also given. This is a large diameter urban highway tunnel that has been excavated successfully with a single shield TBM. Also the planned Lysaker – Sandvika tunnel in Oslo has been analysed. This is a large diameter urban tunnel too, like the Martignano tunnel, but will be excavated with traditional Drill & Blast method. Due to the very similar environmental, technical and geological aspects between these two tunnels a comparison of the excavation methods was done based on the results obtained in the Martignano tunnel project. The conclusion from this and the analyse made of the different factors is that when excavating in an urban area, excavation with a TBM has many environmental advantages compared to the Drill & Blast, and should always be considered in urban tunnel projects. What regards the Lysaker – Sandvika tunnel, it can be mentioned that several of the negative environmental impacts that are expected during construction of the tunnel, can be reduced to a minimum if choosing TBM as excavation method.

Bådsvik, Camilla Y. (R.A. Kleiv)

Fysiske effekter på rauåte (Calanus finmarchicus) ved eksponering av partikler fra vannbasert boreslam. Psycial Effects on Calanus Finmarchicus after Exposure to Particles of Waterbased Drilling Mud. The purpose of this paper is to describe the biological effects of drilling mud and cuttings discharged into the sea during offshore drilling. Calanus finmarchicus has been used in these experiments as an indicator species for the effects. C. finmarchicus is a zooplankton that lives along the Norwegian coast, and in the western parts of the Barents Sea; making it a relevant. Many fish species such as capelin, herring and cod depend on this plankton as a food source. The intension of this research is to identify the potential physical effects on C. finmarchicus when it is exposed to mud particles. This paper attempted to describe if these plankton ate the mud particles and whether they were able to dispose it of, or whether it accumulated inside of them after being exposed to the mud particles. This paper also examined if the ingestion of the mud particles had any effect on their ability to float in the water column. Many experiments were carried out through the course of this research. Mud was analyzed to determine its chemical composition. Toxicity to C. finmarchicus was measured to determine if exposure to the mud was harmful, and to decide which concentrations to use in the main experiment. In the main experiment two different exposure concentrations were used. One concentration was similar to the concentration expected when drilling mud is discharged to the sea, and the second concentration was used to determine the effect of extreme exposure. After the exposure period the C. finmarchicus were sedated, examined under magnification and photomicrographs recorded. Image analysis was applied to the photos to determine the lipid content of the animals as the calculated volume of the lipid sac. The sex of the animals was also noted. After examination, their rate of descend were measured. C. finmarchicus was able to feed on the mud particles. The amount of mud ingested by the individual animals appears to be correlated to the fat content in the animals. It was found that the animals with lower fat ate more of the mud then animals with a higher fat volume. It was found, that females ingested more mud than male C. finmarchicus copepods. During the recovery period the C. finmarchicus were unable to get rid of the ingested particles, even though the time period was theoretically long enough for them to go through the digestive process. While the presence of the mud particles does not affect their ability to stay afloat, the fat content in the animals does. The results from these studies are insufficient to determine whether or not C. finmarchicus is adversely affected by drilling mud discharges.

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Carlsen, Jane Helen (B. Brattli)

Oljeforurensning i marine løsmassesystemer – penetrering og retensjon av olje i sedimenter. Oil Contamination in Marine Deposits – Penetration and Retention of Oil in Sediments. This diploma thesis describes mainly experimental studies of oil behaviour in sediments related to possible environmental consequences from oil spills reaching the shore. The experimental work is discussed in connection with the petroleum activities at the Norwegian Continental Shelf with possible discharge scenarios and typical characteristics of seashores and beach sediments. A column system is used at SINTEF Marine and Environmental technology to study penetration and retention of oil in sediments. Experimental methodoloby and strategy is developed based on previous research at SINTEF and internationally. Different parameters is studied and involve type of oil, different disintegration mechanisms, amount of oil loaded and sediment grain sizes. The results show significant destiny differences of different type of oils. The disintegration mechanisms are vital for the oil interaction in sediments and depend on the water content and degree of evaporation. It is shown that a thicker oil film results in a deeper penetration and retention and that increasing grain size gives corresponding results. These results can be explained from the physical properties of the oil as density, viscosity and pour point. Oils with pour point over the experimental temperature show not to interact with the sediment. The viscosity will be of major importance for oils with pour point under the experimental temperature.

Daniloff, Roger (K.L. Sandvik)

In-situ burning of oil spills. In-situ burning is the controlled ignition and burning of an oil spill at or near an oil spill site. In-situ burning is recognised as a suitable oil spill response tool under arctic conditions, where it can be the only available and effective response tool. The main concern connected to in-situ burning is emissions of combustion products to the atmosphere and compromised safely to humans and human resources in the vicinity of in-situ burning of oil. Feasibility of in-situ burning is strongly related to oil specific properties and weathering processes. The potential to minimize environmental impact of an oil spill, high removal rates, high removal efficiency and low cost connected to this response tool are factors that promote use of in-situ burning in future oil spill situations. This master thesis consists of three parts; a literature study, a laboratory burning experiment and a field experiment. The overall object of this thesis has been to find differences in feasibility of in-situ burning dependent on oil type, degree of evaporation and water content. Temperature measurements of the burning oil have also been a part of the thesis work. Three different oils have been investigated in the laboratory; the Statfjord A crude oil, the Troll B crude oil and the Balder crude oil. The Statfjord A fresh crude oil burned with an efficiency of 69,9%, the Troll B fresh crude oil burned with an efficiency of 57,7% and the Balder fresh crude oil burned with an efficiency of 51,7%. The laboratory burning experiments confirmed that burning efficient decreases with increasing degree of evaporation and water content. Burning efficiency of the Statfjord A and Balder oil decreased with increasing degree of evaporation, with burning efficiencies respectively of 46,5% and 44,0% when burning the 250+ evaporated oils. The Troll B oil burning efficiency decreased with degree of evaporation, but proved to be less vulnerable to evaporation than the other oils. The water-in-oil emulsions burn with lower efficiencies than the fresh and evaporated oils. The Statfjord A water-in-oil emulsions are ignitable and burnable after extensive weathering, the 250+ evaporated, 60% water content burned with an efficiency of 22,7%. This particular emulsion is equivalent to maximum weathering of this oil and it is likely that it can be burned after more than five days of weathering at sea. The Balder and Troll B water-in-oil emulsion proved hard to ignite and burn. The Balder 150+, 25% water content burned with an efficiency of 17,6%, whereas the Troll B 150+, 33% water content burned with an efficiency of 26,4%. The window of opportunity for in-situ burning of these oils is in the order of a few hours at sea. The efficiencies found in the laboratory burning experiments are lower than burning efficiencies found in other laboratory experiments, but the results obtained from this study illustrate the relative differences between the oils and water-in-oil emulsions investigated. Feasibility of in-situ burning is highly dependent on oil specific properties and weathering. The temperature in the combustion exceeds 600oC in most burning experiments. Temperatures do not deviate significantly considering different oil types, degree of evaporation and burning of water-in-oil emulsions. The field experiment took place in van Mijenfjorden on the Svalbard archipelago. This experiment was part of a joint research program, where in-situ burning was evaluated as a clean-up tool. 3400 litres of Statfjord crude oil was pumped under the ice in March. This oil melted up through the ice and was burned in-situ in the end of May. The in-situ burning of this oil resulted in a burning efficiency of 95,3%. Not all oils are appropriate for in-situ burning, this has to be taken into

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account when planning oil spill response. In-situ burning may be the only practical and effective oil spill response tool in arctic areas, particularly in situations where ice is present on the sea surface.

Gjestland, Ida Camilla (K.L. Sandvik)

Ytelse til siktemaskiner og sikteduker med et eksempel fra Oseberg B. Performance of Shale Shakers and Shaker Screens with an Example from Oseberg B. The drilling fluid has several functions, but the most important function is to bring excavated cuttings from the borehole to the surface. To be able to perform its functions, the drilling fluid is given viscosity and density. Cuttings must be removed from the well and separated from the drilling fluid before disintegrated into smaller particles. Smaller particles are more difficult to remove, and the amount of drilling fluid attached and discharged together with cuttings is proportional to the size of the cuttings. If the solids removal equipment does not work properly, the amount of cuttings in the drilling fluid can be decreased by dilution. A shale shaker is the first stage of cuttings removal at the flow line. The purpose of the shale shaker is to remove as much cuttings as possible without removing too large a quantity of drilling fluid. The shale shaker transfers vibration to a screen. The motion can be unbalanced, circular, linear or balanced elliptical. The shaker screens consist of a cloth mounted on to a frame. The screen can be flat, three-dimensional, have one or multi layers, be tensioned on the rig or pre-tensioned from the supplier. The drilling fluid together with cuttings smaller than the screen aperture passes through the cloth and is returned to the active drilling fluid system. The cuttings larger than the screen aperture, with appendage of drilling fluid, are conveyed off the screen. It is desirable to minimize the amount of discharged waste to reduce expenses and environmental impact. The efficiency, dilution factor and drilling fluid expenses per drilled meter are calculated from data presented in a Field Service Report (FSR). The FSR contains results from a mud check performed at the rig. Four scenarios are chosen to evaluate the efficiency on different terms based on days where the efficiency is above 0% and up to 100%. The four scenarios are based on different terms: Number 1 uses all days when the efficiency is above 0% and up to 100%, number 2 is based on days when the activity is drilling, number 3 is based on days with good dilution factor and number 4 is based on the four days in each well with the largest amount of excavated cuttings. Expenses related to the daily usage of drilling fluid per drilled meter are calculated from the dilution factor. The results indicate that the dilution factor, efficiency and expenses have not improved significantly in any of the chosen scenarios after installation of new shaker on Oseberg B. The efficiency of both the old and new shakers is calculated to be slightly above 80% even though the motions are quite different. To find the overall shale shaker efficiency and expenses, three different ways to evaluate the efficiency must be evaluated together and the calculations are only based on the two first principles: The amount of cuttings that the shale shaker can separate from the drilling fluid, the amount of drilling fluid that is lost at the solids control equipment and the flow rate that the shale shaker can handle. Expenses are in addition related to screen usage, which is dependent on the life of the screens. The efficiency is high if large amounts of cuttings are separated from the drilling fluid, if the amount of drilling fluid lost at the shakers is low and the flow rate that the shale shaker can handle is high. It could be concluded that the best choice is to keep all five shale shakers and save expenses related to new installations. A suggested improvement cannot be made based on the calculations in this report.

Holthe, Mari Kristina (B. Brattli)

Grunnvannskvalitet ved prøvepumping av løsmassebrønner til Støren vannverk. Asplan Viak AS has on behalf of Midtre Gauldal kommune investigated the possibility for groundwater as water supply to Støren waterworks. Based on investigations performed by NGU and Asplan Viak, two production wells are established on Folstadøra, south of Folstad bridge. Both chemical and physical processes in the ground will contribute to the groundwater characteristics. Weathering and dissolving of minerals, adsorption of ions and transport of ions along with the groundwater flow are important mechanisms that eventually will give the groundwater its character. Test pumping of both the production wells was started 27.01.06 and is still going on. Water samples have been collected during the test pumping and samples have been sent to NGU for chemical-pyhysical analyses. For bacteriological analyses, samples have been sent to Gaia lab. Lowering of the water table has been measured during the test pumping except during periods of flooding.

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The bacteriological analyses show that there are periods when bacteria‟s occurs in the production wells. According to the water supply law (Drikkevannsforskriften), there shall not be bacteria‟s in the drinking water. The bacteria‟s is most likely to come from Folstadbekken that passes through the well area. The sides and the bottom of Folstadbekken have been covered with clay and sand to try and stop water drawing directly into well 2. From the results it seems that the project has been partly successful. The recipient time is possibly shorter than 60 days since bacteria‟s are found in both well 1 and well 2. The recommended disinfection method is UV-treatment; which is effective against both bacteria‟s and other micro organisms.

Høien, Are Håvard (B. Nilsen)

Steinbergtunnelen – Ingeniørgeologiske problemstillinger for rundkjøring i berg (i samarbeid med Statens vegvesen, Sør-Trøndelag). Tunnel Steinberget – engineering geological considerations for subsurface roundabout (in co-operation with Statens vegvesen, Sør-Trøndelag). Engineering geological aspects of planned underground roundabout in the Steinberget tunnel, at the time of the thesis work under construction as part of the “Nordre avlastningsvei”-project in Trondheim, have been analysed. The thesis represents a follow-up of a project work carried out by the student in the autumn semester 2005, reviewing the engineering geological conditions of this tunnel project. As an introduction, experience from roundabouts previously built in rock is discussed. Main emphasize is then placed on discussing the following factors regarding the roundabout: 1) Alternative principles for excavation and optimization of excavation relatively to the geological conditions, 2) Stability conditions and alternatives for rock support, including support prognosis and time/cost estimate, and 3) Possibilities for adjustment of planned geometry and location. Supplementary engineering geological mapping in the tunnel has been done as part of the thesis work, and for analyses of the roundabout numerical modelling based on Phase2 and CATIA 3D has been carried out.

Kruuse-Meyer, Randi (T. Myran)

Avrenning fra tunnel. Analyser av vann- og slamprøver under drivefasen med sprengningsarbeid. Runoff from tunnels. Analysis of water and mud samples during construction of tunnels by blasting. Runoff from tunnels and depositing of rocks from blasting and mud during construction of tunnels may pollute the areas around the construction site. Sampling and analysis of water and mud from three different tunnels, that is Frodeåsen tunnel (Tønsberg), Sørdalstunnelen (Lofoten) and Eiksundtunnelen (Møre og Romsdal), have been performed to get an indication of the extent of the pollution. The samples were analysed for content of nitrogen compounds originating primarily from blasting, as well as oil and PAH, suspended solids and organic materials. Furthermore pH, alkalinity, conductivity, heavy metals, as well as some other elements such as natrium and calcium were analysed. Most of the samples had elevated pH-values and a high content of calcium, which could indicate cement residues from injection and shotcrete in the samples. There was also detected ammonium and other nitrogen compounds, which is associated with residues from un-detonated explosives. The contents were greatly reduced from the blasting area to the outlet, but sedimentation seems uneffective for nitrogen reduction. The content of oil and PAH was negligible, but the samples from Eiksundtunnelen had much higher contents than samples from the other tunnels. The contents of suspended solids in the water samples from the outlet of the sedimentation containers at the construction site of Eiksundtunnelen and Frodeåsen was 730 mg/l and 956 mg/l. These values would in many cases have exceeded specific water regulations, that customarily indicate levels in the region 100-400 mg/l, depending on the type and vulnerability of the recipient. One mud sample from each is characterized morphologically and mineralogically. The analysis showed that the sample material had a high content of particles with sizes < 74 µm, and the content of particles with roundness < 0,5 was below 20% in all the samples. The percentage was slightly higher in the sample with the lowest grain sizes than in the sample with coarser grains. There was also performed mineralogically characterisation of rock samples from two of the tunnels. The bedrock at the locations of the tunnels consisted of igneous rocks with porphyritic texture (Oslofeltet) and different types of gneisses. The analysis showed that there was a high content of feldspar in all the rock samples. The mud samples differed from the rock samples with a content of calcium carbonate (CaCO3), which is the main compound in cement. The findings in this study indicate that the processes running in the tunnel, such as blasting and the use of shotcrete, influence the contents in runoff. It also indicate great variations and the need for a more thorough study to draw conclusions and generalize.

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Napit, Dinesh Kumar (S. Lippard)

3D Seismic Interpretation and Wireline Log Analysis to Study Seismic Stratigraphy, Lithofacies and Features in the Lower Tertiary Sequence of the Glitne Area, North Sea. Seismic stratigraphy, lithofacies and features are described in the Lower Tertiary sequence of Glitne area, North Sea based on 3D seismic interpretation and wireline log analysis. The Lower Tertiary rocks of the Glitne area are divided into the Rogaland and Hordaland Groups. The seismic characteristics of the Rogaland Group show laterally persistent sub- parallel reflections between the prominent Base Tertiary and Top Balder reflectors. The Hordaland Group shows two different units: Chaotic Facies and Faulted Facies. The Chaotic Facies is characterized by chaotic internal reflections and V-shaped brights. The chaotic internal reflection zones comprise short, disconnected internal reflections and low amplitude reflections. Based on wireline log analysis this facies is further subdivided into Lower, Middle and Upper Chaotic Facies. The Lower Chaotic Facies is characterized by thick succession of low density-velocity smectite rich shale, the Middle Chaotic Facies is characterized by thick sandstone succession with intervals of low density shale and the Upper Chaotic Facies is characterized by both high and low density shale. The Faulted Facies is more organized and is further subdivided into Lower and Upper Faulted Facies. The Lower Faulted Facies is characterized by a thick succession of shale and the Upper Faulted Facies is characterized by a thick succession of shale with thin intervals of sandstone. The seismic features of the area include local to regional seismic reflectors, fault systems and sand intrusions. Base Tertiary, Top Heimdal, Top Balder and Top Hordaland reflectors are most prominent in the area. On a regional scale they show the effects of the underlying Jurassic high forming a domal or anticlinal structure in the Glitne area which extends up to the top of the Rogaland Group (Top Balder) but it is not clear by the top of the Hordaland Group. Several different fault systems in the area are recognized : N-S and E-W trending normal faulting at Top Heindal and Top Balder possibly related to the domal structure of the Glitne Field over the underlying Jurassic high; NW-SE trending normal faulting at Top Balder possibly related to deeper Jurassic structures representing regional structural trend; NW-SE trending reverse faulting at Top Balder possibly related to sand intrusions underneath, and polygonal faulting in upper part of the Hordaland Group which is apparently unrelated to the deep structures. Two types of sand intrusions are identified: tabular wing-like sand intrusions below Top Balder and conical sand intrusions in the Lower Chaotic Facies of the Hordaland Group.

Oanes, Ole Jakob Tau S. (K.L. Sandvik)

Optimalisering av malekrets ved Titania AS. Optimization of Grinding Circuit at Titania AS. The main scope of the work presented in this report has been to provide Titania AS with a summary of the potential for optimization of their grinding circuit. Optimization can only be seen in relation to the following separation processes, and an evaluation of losses caused by slime production or poorly liberated ilmenite has been an important part of this project. The evaluation of the product produced in the grinding circuit, and its distribution downstream, shows a slime loss of about 10% of the total tonnage and about 9% of the total feed of TiO2 in the secondary cyclones. Ilmenite liberation studies show a total liberation of the ilmenite of about 83%. For the remaining 17% of non-liberated ilmenite approximately 5% is in the fractions above 212 µm. The statement that fractions above 212 µm are poorly liberated has earlier been a weighted factor when revising changes in the grinding circuit. However, the interpretation of survey provided in this report shows that the amount of non-liberated ilmenite in these only comprise of about one tenth of the total amount of material produced over 212 µm and only about 2% of the total tonnage produced in the grinding circuit. Two preliminary experimental campaigns were conducted in order to evaluate a full scale experiment initiated by Titania, and to evaluate the potential for changes in the grinding product/circuit by adjusting circuit variables. The campaigns show a potential capacity increase of up to 30% for mills 1, 2 and 3 if a relatively coarser grinding product can be accepted. The campaigns also show a potential decrease in slime production as a consequence of a coarser grinding product. The results from the work presented in section 1 and 2 of the report gives a good basic when considering what can be interpreted at an optimized grinding product at Titania given their available grinding and separation circuits. Considering the results given in sections 1 to 3, it is the author‟s opinion that Titania, with the equipment available at present, relatively simple can achieve a two-stage grinding situation where only the non-liberated ilmenite is sent to regrinding. By this Titania may potentially achieve:

 Increased total capacity  Lowered slime production

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 Increased liberation of ilmenite  Increased amount of material to gravimetric separation circuit  Less regrinding of liberated gangue and ilmenite

Rabben, Elisabeth L. (B. Brattli)

Effekt av tildekking med hyperitt over PAH-forurenset sjøbunn i Drammensfjorden. Effect from Covering PAH-Polluted Seabed Sediments within Hyperite in Drammensfjorden. Over the last few years, investigations of Norwegian fjord and harbour sediments have shown that they contain large amounts of pollutants. Years of release of pollutants from different types of industry have led to large accumulation of heavy metals and organic pollutants. The sediments in Gilhusbukta in Drammensfjorden contains among others, PAH (Polyaromatic hydrocarbons), a group of organic pollutants. Leaking of pollutants from the sediments may cause risk to the environment and ecosystems, and lead to serious health-effects like reproduction problems and damage to DNA, both on humans and marine living organisms. A possible remediation method is to cover up the polluted sediments with a layer of clean masses. NCC has available masses of a type of gabbrorock, hyperite. They wish to use this as a capping material. Hyperite has earlier proved to be a good adsorbent for organic material, and there is therefore reason to believe that it will work well as a capping material, on top of organic pollutants, as well. To try to decide how well the hyperite will work as a capping material, several experiments have been conducted. The hyperite‟s ability to prevent leaking of pollutants from the sediment has been tested through a diffusion experiment. Molecular diffusion of PCB and PAH from a polluted sediment has been registered, both with and without capping. Transport of PAH through capping by capillary forces has also been measured. In addition, the effect on the sedimentation process by adding capping materials to a suspension of sediment and water, and the effect on the PAH content in the water are tested. The results are compared with similar experiments conducted with capping layers of fluvial sand, Svelviksand. The results from the diffusion experiment shows that the tests including a capping layer of hyperite retains 73% of the total diffusion from tests on sediment without capping. The tests capped with Svelviksand retain 60% of the total diffusion. The retention capacity of hyperite is therefore considerably better than Svelviksand. Diffusion of PCB from polluted sediment was not detectable with the analysing methods that were used. The transport of PAH through layers of capping is not very high, neither for capping with hyperite nor Svelviksand. Adding capping materials to a suspension of sediment and water increases the sedimentation rate, as a consequence of increased flocculation in the suspension. There is no evidence that the adding of hyperite causes other effects on the process than adding Svelviksand. Analyses of PAH-contents in water samples show that adding Svelviksand to the suspension decreases the PAH-content compared to adding hyperite. This may be caused by the fact that hyperite contains more fine-grained particles that will stay in suspension compared to Svelviksand. These fine-grained particles may adsorb PAH compounds, and therefore increase the concentration in the water samples. When taking the results from all experiences carried out into account, it appears that the capping performance of hyperite is better than of Svelviksand for the polluted sediments in Gilhusbukta.

Ragvin, Sissel Nicole (B. Nilsen)

Åknes skredområde – numerisk modellering ved hjelp av PLAXIS (i samarbeid med ICG, NGI og Åknes/Tafjord- prosjektet). Åknes landslide area – numerical modelling based on PLAXIS (in co-operation with ICG, NGI and the Åknes/Tafjord- project). As a follow-up of project work carried out in autumn 2005, focusing on collection and interpretation of extensive engineering geological data, stability analyses based on PLAXIS 2D finite element code have been carried out for the Åknes landslide area, where distinct signs of displacement are represented by large, open discontinuities. The thesis is included in a comprehensive research programme on rock slope stability. As basis for analyses, relevant models concerning geometry and geology have been designed. Main emphasis in numerical analyses has been placed on: 1) Analysis of the possibility of sliding along complex combined sliding planes, and 2) Analysis of the possibility of failure developing between sliding planes through bridges of intact rock. Extensive parameter studies have been included in the PLAXIS analyses. Most of the situations that have been analysed give FS>1.2, but water in combination with low roughness gives FS<1.2.A very interesting is that deep seated sliding plane (i.e. >100m) gives considerably lower safety factor than more shallow ones. Location and continuity of the sliding plane(s), water pressure and global roughness are found to represent the greatest uncertainties in the analyses and should be looked upon in more detail.

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Sellgren, Kari Charlotte (K. Rokoengen)

Kvartærgeologisk utvikling av Tillerområdet i Trondheim. Quaternary Geological Development of the Tiller Area in Trondheim. This report provides an overview of the Quaternary development of the Tiller-area in Trondheim. The overview was obtained through studies of previous work, geotechnical drillings, ground penetrating radar, soil properties, air photo- studies, fieldwork in specific areas and radiocarbon dates. The interpretations are based on research material gathered from Ekle Gravel pit, the area around Gamle Tiller Kirke, Kvammen and Quality Hotel in the Tillerbyen-area. The report has been divided into two main sections: Investigations of depositions in connection with the Younger Dryas-glacial deposits in the Ekle-Melhus-Torgård-Skjøla-ridge (Ekle Gravel pit, Kvammen and Quality Hotel), and investigations of deposits younger than the Younger Dryas-deposits (the area of Gamle Tiller Kirke). The depositions at Ekle Gravel pit, Kvammen and Quality Hotel, were examined to illustrate the formation of the ice marginal-deposit. The deposits were divided into three main units at Ekle Gravel pit; 1. Clay located in the lowest part of the gravel pit, 2. Sand and gravel, 3. Clay located on top of the gravel pit. The over-consolidated clay, discovered in the lowest part of the gravel pit, was probably deposited as glaciomarine clay during the Allerød chronozone (11.800- 11.000). During the ice front advance from the Klæbu-area during the Younger Dryas chronozone, the glaciomarine clays were consolidated to form till. Overconsolidated clay from the Quality Hotel-area was examined and radiocarbon dated 11.000±60BP, which indicates a later ice front advance. This ice advance may be a result of a glacier moving in from the fjord. Structures in the sand and gravel deposits at Ekle Gravel pit indicate that glaciotectonics may have influenced the area. The very firm clay on top of the Ekle-Gravel pit indicate that glaciotectonics may have influenced the area. At the Gamle Tiller Kirke-area mainly a remaining gravelridge was examined. Two theses have been proposed for the deposition of this gravelridge: 1: The ridge is a supply-esker, and 2: The ridge is part of a fluvial delta. The main purpose of the surveys at Gamle Tiller Kirke was to determine the deposition characteristics of the gravelridge, and to examine a possible landslide-depression located south of the gravelridge. The ridge was probably deposited 10.100-9.800BP as a Gilbert-type delta. Several landslides have later developed in the same area. In addition to other landslides described earlier, a landslide probably developed further south (by Moan). However, the age of this landslide is unknown.

Sellæg, Torbjørn (E. Broch)

Prosjektering av transportbåndtrasé Ørin – Tromsdal. Design of a Conveyor Belt between Ørin and Tromsdal. Verdalskalk is planning to increase the annual production of limestone in a quarry at Tromsdalen 0.8 to 4.5 million ton. For this increased production a new transport system from the quarry to the harbour has to be established. The thesis analyses an alternative with a 13.255 m long conveyor belt. 9.075 m of the belt is planned to go through a tunnel. The rocks along the tunnel alignment are limestone, phyllite and greenstone of Cambro – Silurian age. Excavation of the tunnel by the conventional Drill&Blast method as well as by TBM has been studied. The study indicates that the fastest and most economical method is Drill&Blast applied on four tunnel faces. The size of the tunnel should be 22 m2.

Størksen, Hanne (B. Brattli)

Miljøvurdering av to deponeringsalternativer for vannbasert borekaks. Evaluation of Environmental Impacts from two Alternative Deposition Methods of drilling Mud from Drilling Operations in the Barents Sea. The petroleum industry has already initiated their activities in the northernmost parts of the Norwegian continental shelf. The fisheries are no longer the only main activity in these areas. As the petroleum industry is becoming more important. A series of laws and regulations apply for all activity in these sea areas, and especially the petroleum industry has to fulfil strict environmental demands. After the investigations of the consequences of all-year petroleum activity in the areas of Lofoten – Barents Sea, it was set as a prerequisite that there should not be any discharge to sea from drilling operations. The exception was for drilling of the upper section of the well, the top hole section. The result of the investigation suggests two alternative solutions: reinjection to the formations or transport and deposition on shore. Eni Norge started the drilling of well 7122/7-3 in October 2005, and drilling waste was shipped to shore, including water-based drill cuttings. This paper will take a closer look on this solution, and compare it with the effects of discharge to sea of water-based drill cuttings. Drilling cuttings and drilling mud was sampled during the drilling operation the winter 2005/2006, and sent to the laboratory Bioforsk before the work with this paper was initiated. The results from the analyses made the base for a risk

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assessment of the two solutions for drilling cuttings, considering it as polluted sediments and polluted ground onshore. By comparing the concentration with limit values set by the pollution authorities (SFT), the risk of environmental impact was assessed. The effects of dilution were also assessed. The dilution factor is expected to be large for discharge of water-based drilling cuttings to sea, both in the water column and in the settled particles. Reduced concentration due to leaching and run-off from the cuttings were also assessed. It is a known fact that the dilution is much more significant with discharge to sea than with deposition on-shore. The drill cuttings must be classified as waste. This was done by comparing the measured concentrations of dangerous components in the cuttings with limit values for dangerous waste set in regulation “avfalls-forskriften”. None of the limit values were exceeded, and the conclusion is that the cuttings can not be classified as dangerous waste. A life cycle assessment was carried out to compare the two alternatives. The assessment focused on some chosen parameters, such as transport route (and length) with CO2 emissions, risk of accidents, ecological risk and land use. Economy was not included in the assessment, as it is on forehand obvious that deposition on shore is significantly more expensive than discharge to sea. The assessment argues for that discharge to sea is the solution with least stress on the environment.

Svendgård, Camilla (T. Myran)

Nitrogendioksyd (NO2) ved tunneldriving – Konsekvens ved reduksjon av administrativ norm Nitrogen Dioxide (NO2) in Tunnelling Works – Consequences by Reducing the Treshold Limit Value (TLV)

Tobiassen, Bård (K.L. Sandvik)

Development of an In-situ remediation Technology for an Aquifer Contaminated with Acid Mine Drainage. This thesis presents a total picture of all AMD generating and releasing sources at IDP. The AMD polluted plume is visualized in a GIS. Earlier AMD studies at this area have mainly focused on only two polluting sources; the old evaporation ponds, and the old waste rock dump. This is probably because those are the immediate eye catchers. The main objectives in this study were to delineate the extent of the polluted aquifer down gradient of the old evaporation ponds, and to find an implemental remedial intervention. During the fieldwork, it came clear that there had to be other sources generating AMD, in addition to the old evaporation ponds, and old waste rock pile. These results reviled that other units than those first assumed, were the largest contributors to contamination of the environment. A pilot scale of an Anoxic Limestone Drain (ALD) was implemented in the AMD polluted groundwater. The ALD pilot consisted of one metric ton of limestone. The ALD failed to treat the acidic water immediately after construction. The main reasons for immediate failure was armouring of lime by aluminium and iron that was not known prior to the experiment. A standard method for monitoring the overall AMD contribution at IDP was implemented. By measuring conductivity and water height at a v-notch, down gradient of the entire study area, estimation of the sulphate flux was made possible. The sulphate flux was then used in prediction of the present oxidation rate, given as mass of pyrite per year. The most suitable technique for remediation would in this case be to cover the AMD generating sources. Covering should include barriers against water and oxygen intrusion, to decrease mobility and generation of AMD. Further characterization of the different types of waste rock deposited in the area can be of economical value in terms of “discovering” new resources.

Aal, Anders (B. Nilsen)

E6 Nidelv bru – Grilstad; Stabilitet og sikring i tunnel under Kuhaugen (i samarbeid med Statens vegvesen, Sør- Trøndelag). E6 Nidelv bridge – Grilstad; stability and rock support in tunnel under Kuhaugen (in co-operation with Statens vegvesen, Sør-Trøndelag). In this thesis stability and rock support requirement have been analysed for the planned, approx. 2 km long, two-tube road tunnel beneath Kuhaugen in Trondheim. Particular emphasis is placed on analysing challenges related to sections of limited rock cover. The thesis represents a follow-up of project work carried out during the autumn semester 2005, which was focusing on a review of the engineering geological conditions and discussion of potential problems due to

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groundwater ingress and blast vibrations. In the thesis work, the following factors have been in main focus: 1) Particular problems related to the entrance areas, 2) Challenges related to crossing of fault zones and sections of weak rock (soapstone), and 3) Possibilities for adjustment/optimization of tunnel alignments and distance between the two tubes. Prognosis for rock support requirement has been made, and cost and schedule estimated. As main tools for evaluation, empirical data, the Q-method and Phase2 FEM-code have been used.

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2005

Bergström, Jani (B. Brattli)

Risk and Status Assessment of Groundwater Resources in Norway. Groundwater is the most important natural resource on Earth. Exploitation and protection of fresh and groundwater is one of the biggest scientific and economic interests. Various countries and scientists developed methods and tools to explore groundwater resources, ensure water constant quality, and perform artificial recharge to supply freshwater for people. Water resource management with international and regional legislations and regulations is one result of this deepening interest. The European Union Committee passed for this purpose the Water Framework Directive (WFD) with the ambitious goal to reach “Good Water Quality” in all European Union countries and Member States. This thesis is an attempt to provide a methodology for the risk assessment of groundwater bodies to help with this cause. For Norway, risk assessment is a rather new subject in hydrogeology. A partial examination of hydrogeological resources, abstraction points and other influence factors was performed, but no unified methodology was developed. To fulfil the WFD criteria, this is a basic requirement and gives additional motivation for this work. Shortly, the factors affecting the water cicle and groundwater are represented. All those factors are described with respect to the conditions for geology, location and climate in Norway. The work concentrates solely on the risk and status assessment for groundwater bodies in Norway, and mentions the other necessary measures to fulfil the WFD criteria just briefly. This work bases on a combination of methodologies and tools from different countries, adapted to the Norwegian conditions. The way of combining those methodologies and the adaptation of those reflects the subjective opinion of the author. In the end, the final product is the result of a thorough screening of all available data. Based on all this data, a new, more generalized, methodology for groundwater risk assessment in Norway was developed. The development of this methodology took place with the purpose, to give an intuitive tool for the assessment of groundwater bodies. To achieve this goal, some limitations had to be taken into account. This concerns mainly the information content of the result. It does not reflect a quantitative description of the risk status, merely a qualitative classification. If a quantitative description of the area is needed, including threshold values for the contamination by specific elements, a closer examination by experts, based on the results of the qualitative assessment, has to be performed. The validity of the methodology was verified by applying it to a case study at the Numedal 2 groundwater body. This verification can be considered as successful with respect to the simplicity of the method and gives in the eyes of the author a good basis for a further and more precise evaluation of the area. Even though only one case study was performed, the author judges the developed methodology as generally valid but can not exclude the need for slight adjustments.

Bich, Le Thi Ngoc (E. Broch)

Tunnel Design for the Ban La Hydropower Project in Vietnam.

Ban La hydropower project is located in Ca River, Yen Na commune – Tuong Duong district – Nghe An province in the central part of the Social Republic of Vietnam. The main objectives of Ban La HPP are to supply electricity for Vietnamese national grid and developing economy and society of project area and to control flood for dolwnstream area. The project also provides water by utilizing water release for irrigation. It is also explected to poritively change the local climate due to creation of the reservoir. The project composes of a RCC gravity dam, a spillway in the middle of the dam, waterway with headrace tunnel and opened powerhouse (320MW) on the left bank. Geological investigastion for the 1st stage of the technical design phase by PECC1 made out that recommended project area is located in sediment rocks having various components of sandstone, aleurolite, argillite, shale, siliceous shale, conglomerate, gritstone, limestone. In this thesis, the headrace tunnel of Ban La has been studied as follows: The location and alignment of openings have been studied based on the available data of weathering rock layers, topography characteristic, joint sets information and stress condition in the area. The shape and dimension of headrace tunnel are optimized and designed by applying Norwegian method including cost curve of construction and electricity price.

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The RMR and Q methods have been used for rock mass classification and by thus the rock support method are designed. The supports have been reviewed in consideration of the results from numerical analysis. The PHASE2 model is also used in the thesis to evaluate stress condition in rock mass, to check strength factor, yielded elements and displacement, the optimum distance between the tunnel and to analyse rock support. Base on the studied results, some recommendations have been made out for the recent design and further studies.

Dahl, Per Kulseth (R. Sinding-Larsen)

A Technical Economic Evaluation of Oil Recovery from a Gas Discovery with a Thin Oil Zone. Troll Field as an Analogue to a Hypothetical Snøhvit Project.

Eikanger, Oddbjørn (S.O. Johnsen)

Use of the modeling program SBED on fluvial deposits. The Lourinha Formation in Portugal is regarded as an analogue to the Statfjord Formation in the North Sea, both consisting of fluvial sandstones and mudstones. Using the modeling program SBED to create three-dimensional geometrical models of the Lourinha Formation, and then populating these models with reasonable petrophysical values, gives a representation of a meandering fluvial system that is comparable to the Statfjord Formation. Variation of input parameters like sand content and channel sinuosity gives predictable and reasonable results when calculating petrophysical values like porosity and permeability. The variations in input parameters have a large effect on these values, making it important to have maximum possible knowledge of these parameters. The upscaling results show increasing permeability and porosity with increasing sand content in channel lags, and with increasing channel sinuosity. Because the main flow direction of the river is set to be along the x-axis, the results also show better permeability in x-direction than in y-direction. SBED proves to be a useful tool in modeling depositions of a meandering river system, and can help giving a better understanding of the characteristics of the Statfjord Formation and other similar reservoirs.

Forfang, Ingunn Kristin (K.L. Sandvik)

Reduksjon av nikkelutlekking fra Titanias landdeponi.

Furseth, Linn M. (R. Myran)

Svevestøv og støvnedfall fra norske pukkverk.

Khadka, Dharma Raj (S. Lippard)

1D Basin Modelling for Assessment of Hydrocarbon Prospectivity: A Case Studies from the Exterior Belt (Terai) and Siwalik Fold and Thrust Belt, Exploration Block 2, Western Nepal.

Long, Le Ba (E. Broch)

Slope Stability Analysis for Ban La Hydropower Project in Vietnam. In Vietnam, slope stability is of great concern, not only for hydropower projects, but also for road cuts and open pit mines. Ban La Hydropower Project is located on Ca River, Nghe An Province, in the central part of Vietnam. Main objectives of the project are power generation, irrigation, water supply and flood control. The project composes of a Roller Compacted Concrete (RCC) main Dam, 2 parallel underground headrace tunnels and an open air powerhouse. At the main dam area of Ban La HPP, slopes are composed of rocks of various types, differing in strength, water- physical property and the degree of weathering, therefore, the structure of these slopes are rather complicated. Their stability during and after excavation in different conditions is of great concern for the success of the project. The thesis aims to analyse the stability of the high rock slopes at the main dam area. Stereographic projection is performed to identify potential failure modes which could control the slope stability. Numerical analyses are best suited for revealing the mechanism of the stability problems. SLIDE 5.0 was used in this study. Stereographic projection study of the respective rock slopes indicates that potential plane and wedge failures are possible for both dam abutments. The numerical analysis leads to a considerable insight into the overall slopes stability

33 Institutt for geologi og bergteknikk Hovedoppgaver 2005 by conducting parametric studies. The excavation design appears feasible. Due to jointing and high degree of weathering, the rock support is recommended for some local stability problems specially at the toe slopes on the right rifer bank. Finally, some conclusions and further studies on rock slopes is recommended.

Mao, Dawei (E. Broch)

Engineering Geological Analysis of Underground Structures at Mugecuo Hydropower Project. The planned Mugecuo Hydropower Project (Mugecuo Pumped Storage Power Plant) is situated in the Kangding county, western part of Sichuan province, P.R. China. The plant is one of the cascade plants on the Wasi River, the tributary of Daduhe River. The designed installed capacity is 210MW, and the pumping capacity is 140 MW. Main structures of the project are Mugecuo dam, water tunnels, powerhouse and downstream gated weir. Rock types including granite, migmatite, quartzite slate and phyllite are found in the project area. Along the tunnel alignment proposed by the Chengdu Hydroelectric Investigation and Design Institute (CHIDI), the rock can be divided into sections of Granite, Migmatite, Mainly Quartzite, Quartzite and Slate, and Mainly Slate. In the Section of Migmatite, an active fault zone named Qisehai is found. In the preliminary draft of the Mugecuo Hydropower Project, water is diverted from the lined headrace tunnel via the sectionalized pressure shaft to the ground powerhouse. The main objective of this study is to search for the better engineering solution for the project, based mainly on engineering geological analysis. The underground powerhouse and un-sectionalized pressure shaft/tunnel have been studied following the Norwegian design procedure, from choosing the location and orientation, to the selection of shape and dimension. Rock classification systems including RMi method, Q-system and RMR system were used to evaluate the rock mass quality. Estimated rock supports from both RMi method and Q system have been given. To check the rock supports suggested and solve problems for which empirical methods are not well suited, the numerical method was used.

Pedersen, Rune Langlo (M.B. Mørk)

Provenans og diagenese av sandsteiner fra Åreformasjonen. Provenance and Diagenesis of Sandstones from the Åre Formation.

Pradhan, Anand (B. Nilsen):

Rock slope stability problems related to major roads in Nepal –a discussion with particular emphasis on Krishnabhir and Jogimara (in co-operation with ICG). The issue of this thesis is rock slope stability problems related to major roads in Himalayan rock conditions. As introduction, the rock slope stability problems that may occur during construction and operation of major roads are discussed on a general basis, and the main factors that may influence on slope stability in typical Himalayan conditions are described and discussed. Two main cases on rock slope stability problems along major roads in Nepal are then described and discussed in detail. These cases are Krishnabhir and Jogimara, both located along the Prithivi Highway West of Kathmandu, where severe stability problems and several slope failures have been experienced. For these slopes detailed stability analyses are carried out. Potential failure modes and input parameters for calculation are defined based on field observations and available background information, and for calculation, the SLIDE 2D limit equilibrium computer software has been used. The analyses have shown that both landslides areas are critical, and that more sliding activity has to be expected in the future.

Sandbæk, Veslemøy Ylva Maria (S.O. Johnsen)

Prediction of permeability for a complex carbonate reservoir. Carbonate reservoir characterisation is generally more complicated than for siliclastic rocks. This paper presents a description of carbonate reservoir rocks and problems associated with petrophysical classification and permeability measurements. Carbonate reservoirs are infamous for their diverse pore textures. Grains come in all shapes and sizes and diagenesis may alter the original rock fabric in dramatic ways. As pore textures (rock fabrics) control permeability, we need to be able to reveal these from commonly available measurements. The South Pars Field, offshore Iran, contains gas in Permian and Triassic Formations. Moderate porosity – high permeability dolomite and high porosity – low permeability calcite are two of the reservoir rock types that are important.

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Simple porosity-permeability relationships do not exist. In order to come up with a usable permeability model for the South Pars Field, three approaches was done. The Powerlaw model predicted permeability based on simple porosity-permeability relationship. As suspected the model did not work, and a dynamic range between the predicted and the measured core permeability did not exist. Secondly an application within Paradigm‟s Geolog called Facimage was used to make a permeability model and to predict facies. The predicted facies does not relate to the proposed core facies, but it relates to the mineralogy. This indicates that sedimentary facies are not decisive for the permeability in the reservoir. According to the correlation coefficient, the predicted permeability does not correlate well to the core permeability. However, the dynamic range is fairly good, and the model seems to work well in the study wells. In order to use this model on the field, an attempt on relating the predicted facies to geological facies (e.g. diagenetic facies) needs to be done. Finally, a classification of the rock fabric based on thin section photos was done. The purpose was to see if different Rock Fabric Classes could relate to different permeability fields.

Shakya, Munna (B. Nilsen)

Rock slope stability problems related to hydropower - a discussion with Kali Gandaki as a special case. In the first part of this thesis, rock slope stability problems that may occur during construction and operation of hydropower projects in Himalayan rock conditions are discussed on a general basis, and relevant cases from Nepal are described and discussed. As a special case for the study, slope stability issues related to the Kali Gandaki project in Nepal are described and discussed in more detail. Kali Gandaki is a 144 MW run-of river project in the Western region of Nepal that was put in operation in 2002. During construction, stability problems and several slope failures occurred. For critical slopes at Kali Gandaki, detailed stability analyses are carried out. Potential failure modes and input parameters for calculation are defined based on available background information, and for calculation the SLIDE 5.0 limit equilibrium computer software has been used. For evaluating potential risk of future failure of the important desander backslope, probabilistic approach has also been used. A probability of failure of this slope of approx. 5% has been found, but there is considerable uncertainty in this result due to uncertain input-parameters.

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2004

Azad, Md Abdus Samad (M.B.E. Mørk)

Seismic and sequence stratigraphic correlation of Upper Tertiary sediments in mid-eastern Bangladesh, and petrography and diagenesis of reservoir Sandstones of the Salda Nadi gas field. Main content: Seismic, wireline log and core data of the mid-eastern part of Bangladesh have been analysed to interpret the depositional environment of the Upper Tertiary sediments using a sequence stratigraphic approach. Sandstone samples from the Salda Nadi well 1 and 2 were studied by optical microscopy and supplementary methods to discuss petrography, provenance, diagenesis and reservoir quality. The composite seismic section and vertical litholog profiles reveal three major sequences that can be broadly correlated with the conventional lithostrati-graphic successions of Bangladesh; the Bhubon Formation, Boka Bil Formation and the Tipam Group.

Brandsegg, Kristian H. (R. Sinding-Larsen)

Favorabilitetsstudie for olje- og gassfunn I Norskehavet. Assessment of Favourability for Oil and Gas Discoveries in the Plays of the Norwegian Sea, Offshore Norway. The objective of a petroleum exploration program is to define areas favourable for the discovery of commercial quantities of hydrocarbons. Mapping favourability for oil and gas discoveries by integrating diverse geoscience datasets has been attempted in this thesis by the use of systematic weighting of geologic factors. Two recently published methodologies with additional improvements have been used in the Norwegian Sea to quantify the favourability for the existence of new oil and gas fields. The methodology for delineating favourable areas is based upon a cell-by-cell basis where GIS is used to express different geologic factors as present or absent. Later the cells are weighted and probabilistically combined to form favourability maps. Discriminant analysis was introduced to separate dry cells from potential hydrocarbon bearing cells. Geologic variables are used to compute the favourability within a cell and statistical Krieging method is used to estimate a potential closure area. Regression of the existing discovery history in the Norwegian Sea is used to estimate reserves corresponding to this closure area. This study from the Norwegian Sea involves extensive use of GIS and geostatistics to compute influence zones that relate faults and structural boundaries to producible quantities of hydrocarbons. The petroleum data are organized in descriptive models and analyzed against the existing discoveries in order to evaluate the remaining potential of oil and gas in target areas. The study shows that statistical distributions based on geologic features can be used to map zones favourable for new discoveries and may help a company to allocate exploration effort to a region. The results imply that the proposed approach can outline favourable areas and is a methodology that includes the spatial nature of exploration variables. The methodology is capable of favourable mapping in both mature and immature areas with different levels of information. Even sparse information levels may indicate favourable areas if additional data from areas with a high levels of information are included. The study shows the capabilities of integrating geologic knowledge with GIS and geostatistics for fast and accurate evaluation of a study area.

Dahle, Halgeir (B. Nilsen / NGU / International Centre for Geohazards)

Analyse av skråningsstabilitet for Oppstadhornet. Slope stability analysis for Oppstadhornet. Oppstadhornet, a steep mountain on the Oterøya Island West of Molde, shows signs of partly collapse with initial sliding and formation of wide, open joints. As a following-up of earlier, detailed engineering geological mapping and testing, stability analysis of the steep Oppstadhornet slope has been carried out in this thesis work. Several alternatives for analyses have been discussed, and introductory empirical analyses have been done. Main emphasis has, however, been placed on numerical analysis based on UDEC-BB. Back calculation of the situation prior to initial sliding has been done as well as analysis of today‟s stability situation. As an important part of the study, extensive parameter studies have been done. A main conclusion based on this work is that the mountain appears to be more stable today than prior to initial sliding.

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Ervik, Mari Nilsen (E. Broch)

Observations of Ground Movements caused by EPB-tunneling in Singapore.

Singapore in one of the most densely populated areas in the world. Underground development can solve a lot of problems in urban areas like this. In recent years, the government of Singapore has made comprehensive plans for underground systems. Among the projects going on today are the Circle Line, a new line in Singapore‟s Mass Rapid Transit (MRT) system. Construction in urban areas can be very complex. Ground movements are one of the biggest concerns. The Earth Pressure Balanced (EPB) shield machine is one method to excavate tunnels in soft ground. This method can provide stable excavation conditions and limit ground deformations in certain types of ground. There are various methods for predicting ground movements before tunneling, and various instruments to monitor and control the ground during and after construction. The 1st Drive of Contract 822 of the Circle Line, Stage 2, was finished in the middle of January 2004. The ground conditions the tunnels went through were mostly Old Alluvium and Weathered Old Alluvium. The monitoring results showed no major settlements or heave at all, even under unexpected incidents. This confirmed the experience in previous tunneling in the same materials: Old Alluvium and Weathered Old Alluvium are very good ground conditions for EPB-tunneling.

Hansen, John Are (S.O. Johnsen)

Paleogeografisk rekonstruksjon av Firkantenformasjonen (Paleosene) I Reindalenområdet, Spitsbergen. Paleogeographic reconstruction of the Firkanten Formation (Paleocene) in the Reindalen area, Spitsbergen. The Firkanten Formation was deposited in the early Paleocene in the Central Tertiary Basin of Spitsbergen, where it represents the basal formation of the Van Mijenfjorden Group. It rests unconformable above the lower Gretaceous Carolinefjellet formation and represents several episodes of delta progradation with an overall transgressive trend. Facies analysis and sequence stratigraphic correlation of six drill cores in the Reindalen area has revealed that the Firkanten here consists of at least eight sequences, bounded by subaerial unconformities or ravinement surfaces. The vertical stacking of these sequences has an overall transgressive trend and shows a gradual transition from an upper delta plain environment into a delta front (shoreface) environment with gradual eastwards onlap onto the basal unconformity. Deposition of the lowermost part of the Firkanten Formation was in this area largely controlled by the topography of the basal unconformity. During deposition of sequence 1 and 2, represented by a fluvial to upper delta plain environment in the study area, the paleodrainage direction had an approximately N-S trending lineation, following a topographic low in the westernmost part of the study area. As this topographic relief was smoothed out during the final stages of sequence 2, sedimentation was fully initiated in the area east and northeast of this low. A change in the paleodrainage direction also occurred at this stage and the deltas were after this building out towards the west-southwest form an area east-northeast of the study area. During sequence 3 there was still a topographic high, with exposure of the basal unconformity, located in the south-western most parts of the study are and this high probably separated the Svea from the Reindalen sub-basins. The topographic relief was however smoothed out during the early stages of sequence 4 and after deposition of sequence 4 the deltas were probably not longer constrained by the topography of the basal unconformity. After deposition of sequence 8 a rapid transgression occurred and the upper bounding surface of this sequence represents the boundary separating the Firkanten Formation from the prodelta/shelf facies of the Basilika Formation.

Hansen, Tom Frode (B. Brattli)

Analyse av rasutvikling og vannproblematikk i Svea Nord. Analyzing subsidence and water problems in Svea Nord. Svea Nord is the name of one of the northernmost coalmines in the world and is owned by Store Norske Spitsbergen Grubekompani AS (SNSG). The mine is located to 78oN in the innermost part of the Van Mijenfjorden fiord in the central western part of Spitsbergen, Svalbard. Svea Nord is a longwall mine with an average annual production of 2 million tons of coal. Even though the mining so far has been mainly successful, water-problems are an increasing problem. Due to water inflow the summer of 2002 and 2003, the longwall machinery was not operable for weeks. A potential for a major water inflow in addition to this made it necessary to explain the water inflow in the mining area. The amount of water basically enters the mine in mining induced fracture in the overburden. In the summer of 2003 it was possible to observe large mining induced fractures at the Feiselen mountaintop, located vertically over the first mined panel. Fractures with a

37 Institutt for geologi og bergteknikk Hovedoppgaver 2004 length of 200 – 300 m and an expected width of 1 – 2 m almost divided the mountain in two parts. To be able to explain the water inflow to the mine you have to understand the interaction between mining induced fractures of the rock mass, the source of water and its patterns of movement. Collected and calculated data assumes a rapid development of subsidence and the dynamic subsidence constitutes a major part of the final subsidence. The rapid subsidence is mainly explained by a major fracturing of the overburden above the sides of the panel. The surface above the central parts of the panel will therefore subside rapidly. The fracturing can probably be explained by an interaction between the three factors: high rock quality, steep topography and a high stress regime with a large ratio between the maximum and the minimum horizontal stress value. The rock mass will probably fracture more violently in areas with steep topography than in more level areas. The course of events during the water inflow the summer 2002 is according to today‟s knowledge a typical example of a sudden inflow with rather large amounts of water: 1. Fracturing of the rock mass in a zone of 70 – 100 m above the seam, makes the water in the saturated rock mass migrating towards the longwall area. 2. A sudden violent fracturing along the sides of the panel penetrates a water-bearing channel in the surface and large amounts of water percolates to the fractured zone and down to the caving area. 3. A fold- and faulting zone is probably exposed to a certain form of reactivation and this cause an increased permeability in the area. From this course of events you can make the conclusion that the sudden water inflows in most cases is restricted to sudden violent fracturing, as long as there exists sufficient amount of water. In an assumed graben zone in the northern part of the mining area there is low overburden (75 – 100 m) and there are probably occurring large amounts of water laterally or inside the covering glacier. Due to the low overburden it is possible that an estimated 70 – 100 m fractured zone reach the surface. This comes in addition to the contribution from fracturing along the sides of the panel. In the future this area will have a major potential for a major water inflow.

Helgason, Peder Eide (B. Brattli)

Fysikalsk-kjemisk drikkevannskvalitet i godkjenningspliktige grunnvannsverk i Norge. Physio-chemical drinking water quality of groundwater works in Norway subject to certification. In February and March 2004, water samples were collected from 351 groundwater wells distributed between 179 waterworks. The samples were analysed for 32 cations by ICP-AES, 7 anions by IC, and for pH, alkalinity, colour, turbidity and electrical conductivity. Most of the wells were dominated by calcium and bicarbonate. 3% of the water samples were dominated by sodium and bicarbonate. These samples, which were all from bedrock aquifers, had a high pH value and are considered as mature groundwater. The high sodium content is probably the result of weathering processes. 20% of the samples were from immature groundwater dominated by sodium and chloride. These samples had a low pH value, and were from

Quaternary as well as bedrock aquifers. Some of the samples were dominated by Ca-Cl2 og Ca-SO4. The total ionic content in most samples was much lower than expected. This might be because of short groundwater residence time. The groundwater wells can also be influenced by surface water. The concentration of most anions and cations was highest in samples from bedrock aquifers. However, the concentration of nitrate, aluminium and copper was highest in samples from Quaternary aquifers. The pH values of the water samples depended on aquifer type. Samples from Quaternary aquifers had a median value of 7.37, while samples from bedrock aquifers had a median value of 8.17. The samples from the coast of Western and Southern Norway had the lowest pH values. This may be due to lithological variations in soil thickness. Most parameters showed a similar pattern. The hardness and the fluoride concentration in the water samples, seem to depend on the bedrock geology. Hard groundwater was most common in samples from the Caledonian mountain range, while the fluoride con-centrations were highest in samples from bedrock aquifers in granitic rocks. The water samples seem to be moderately influenced by human activity. Nitrate concentrations were lower than in most European countries, but had a distinct correlation with potassium. Fertilizers on agricultural areas are therefore considered to be an important source of nitrate in the groundwater. Some samples with high concentrations of calcium and chloride, can be polluted by salts used for de-icing of roads. 35.6% of the water samples have a quality that fail to satisfy the present Norwegian drinking water regulations. The maximum concentration limit of manganese is most frequently exceeded, with 17% of the samples above the limit.

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Huy, Le Quang (E. Broch)

Engineering geological assessment of the dam site for the Quang Tri multipurpose project in Viet Nam.

Quang Tri Multipurpose Project is located in the central part of Vietnam. Main objectives of the project are irrigation, power generation and flood control. The project consists of a dam and a spillway, and of headrace and tailrace tunnel and an underground powerhouse. The main dam with a maximum height of 85 m is positioned on a complex geological foundation consisting of granitic rocks and gneiss with good quality and relatively thin weathering cover on the left bank. On the right bank ancient soil strata are covered by different basalt flows with various degrees of weathering. These materials, combined with gneiss and schists underneath, make a mix of strong and weak rocks. Further from the river intensively weathered rocks developed on basalt and schists create an overburden up to 80 m thick. Three fault systems are found. An engineering geological evaluation of the dam site is carried out. Missing data are estimated, such as properties of intensively weathered rocks, joint strengths, strengths and deformations of rock masses, etc. Rock masses on the left bank and in the river bed are considered as good foundation, whereas the soil and rock masses on the right bank have various qualities, making a low quality foundation area. This leads to a proposal of a combination of a rockfill dam with central earth core, an earthfill dam and a transition between them. The rockfill dam may be located on strongly weathered rocks and the earthfill dam should on the intensively weathered rocks. Main measures to prevent leakage in the foundation are an integration of cutoff and grouting curtain. Consolidation grouting is necessary in the area of cutoff. An analysis has been done for rock slopes of the dam abutments and around inlet and outlet of diversion tunnels. Stable angles in construction case for each slope have been found. A preliminary design for diversion tunnels proves that the diversion tunnels must be positioned on the left bank. Two unlined tunnels, each with an area of 150 m2, are proposed. Support measures are predicted as mainly systematic bolts, supplemented by an optional layer of unreinforced shotcrete.

Kaldheim, Linda C. (M.B. E. Mørk)

Petrografi og diagenese av sandstein fra Lysingformasjonen, Norskehavet. Petrography and Diagenesis of Sandstone from the Lysing Formation, The Norwegian Sea.

Kvitsand, Hanne M. L. (B. Brattli)

Grunnvannsforsyning til Turhaugen vannverk, Levanger kommune. Utredning av metoder for reduksjon av hardhet i grunnvann. Ground water supply to Turhaugen Water works, Levanger kommune. Reduction of hardness. Asplan Viak AS has on behalf of Levanger kommune investigated the possibilities for upgrading Torhaugen waterworks in Åsen. Ground water supply was considered to be the best alternative and test well was established in a glaciofluvial deposit. Pumping from the test well has shown the aquifer‟s capacity is big enough to cover the waterworks‟ water requirement and that the ground water is of good quality. The concentration of calcium was however so high that any use of the water would imply disadvantages for the consumers. Possibilities for reducing the hardness are therefore evaluated, by investigating the effects of changing the dimensions of the test well and by considering methods for water softening. The first period of test pumping was carried out by pumping from both of the well‟s two infiltration filters. The dimensions of the well were then changed by installing a sealing plug underneath the upper filter to examine the effects this would have on ground water chemistry, retention time and exploitation capacity. Pumping test, water analysis and measurements of the ground water level was completed during both test periods. The concentrations of soda and chlorine augmented during the 2. Pumping period due to larger advection caused by increased exploitation. The increase in concentration of sulphate was caused by greater infiltration of surface water during 2. Period, which in turn lead to enhanced weathering of pyrite. The alkalinity was reduced while the concentration of calcium was more or less the same. The ground water retention time was reduced and the exploitation capacity increased caused by a combination of increased exploitation and favoured ground water flow in the formation‟s upper stratum. Reduction of retention time implies extension of the area of activity restrictions. The test pumping showed that the calcium concentration was not reduced during pumping with the sealing plug. It is therefore necessary to treat the water before distribution to the consumers. Ion exchange is the most effective economical method for softening the water. For water supply to Torhaugen waterworks three ion exchange columns are

39 Institutt for geologi og bergteknikk Hovedoppgaver 2004 needed for softening to acceptable hardness at 4 odH. The waste water‟s salt content will result in an increase of the recipient‟s natural salt concentration from ca. 6,7 mg/l to 6,9 mg/l.

Nesse, Elisabeth (B. Brattli)

Urban avrenning som mulig forurensningskilde fra Drammen og Lier til Drammensfjorden. Runoff from Urban Areas in Drammen and Lier as Possible Source of Contamination in the Drammensfjorden.

Ngo, Quang Huy (R. Sinding-Larsen)

Central African Rift System, Origin of Development and Hydrocarbon Potential. Central African Rift System is often referred to as Central African Rift Subsystem (CAS). It is one of the two major parts that create the Western and Central African Rift System (WCAS) which extends 4000 kilometer from Niger to Kenya. The second part is usually called as West African Rift Subsystem (WAS). These subsystems are related genetically but separated physically. The CAS extends from Cameroon through southern Chad, Central African Republic into Sudan and part of Kenya. The most important Cretaceous-Tertiary rift basins that make up the CAS are the Bongor, Doba, Doseo, Salamat and Muglad. Plate tectonic separation between Africa and South America has played an important part in the rift development. The gradual opening of the Central and South Atlantic oceans from around 130 Ma was responsible for two major phases of basin development in Central African Rift System, the Neocomian-early Aptian and mid Aptian-Albian episodes respectively. The CAS is considered as typical “plassive” type rift which evolved in response to the build-up of intraplate stresses. However, “active” rifting which involves magmatic activities may have a role in the process. The St. Helena hot spot may have weakened the lithosphere across the region at approximately 120 Ma. The Cretaceous-Tertiary rift basins of the CAS are extensional to transtensional and contain up to 7500 meters of predominantly Cretaceous continental clastics. Oil and gas discoveries have been made in most of these basins and production, in its starting stage, has already begun. Heavy to light oil and gas accumulations are situated in Lower and Upper Cretaceous fluvial to lacustrine sandstones reservoirs. The hydrocarbons are sourced from Lower Cretaceous shales and sealed by lacrustrine to flood-plain shale and mudstone, with traps in mainly faulted anticlinal closures. Structural styles vary from simple fault blocks to complex flower structures. Petroleum geology indicates that further potentially commercial volumes of hydrocarbons in these Central African Rift System basins remain to be discovered. Mean estimates of inplace and recoverable resources for the CAS using GeoX/Starter are around 3.98 and 1.51 billion barrels respectively. The Muglad basin alone accounts for more than sixty percent of these figures.

Nguyen, Tra My (E. Broch)

A study of tunnels and underground powerhouse for the Huoi Quang Hydropower Project in Vietnam. Huoi Quang Project is located on Nam Mu River, Vietnam. Main objectives of the project are power generation and flood control. The project composes of a gravity dam, a spillway, and headrace and tailrace tunnel and a underground powerhouse. Maximum head is 150 mm discharge is 420 m3/s and installation capacity 3 x 180 MW. Based on Norwegian approach in designing underground structures the tunnel, the pressure shaft and the powerhouse have been redesigned. The headrace and tailrace tunnels are optimized as unlined tunnels. The Q and RMR method is used to classify the rock mass and the tunnel support is designed based on this method. Numerical models are established to evaluate virgin stress situation, stress after excavation of tunnel and to find the sound location for powerhouse. Recommendations are made in order to improve the models by taken into account some factors, which had not been involving in the created models. The factors are the water table, the excavation of the opening and the support methods.

Nilsen, Kristin Husebø (T. Malvik)

A geological investigation of the Tellnes deposit. The Tellnes ore body is located in the southern part of Rogaland, Norway. A diamond drilling program was carried out in 2004 in the open pit mine and the area east of the pit. These two areas are divided by a crossing lineament. West of the lineament both the geology and how the ore behaves in the process are well known. East of the lineament the information is limited. This diploma thesis has compared these areas. The minerals in the eastern part of the ore body contain other minerals and has a different chemical content compared to the ore in the existing pit and in the crossing lineament.

40 Institutt for geologi og bergteknikk Hovedoppgaver 2004

Data from the geology and the chemical analysis of the cores from the diamond drilling are imported to the existing computer model of the Tellnes ore body. This existing model is evaluated according to how the new information corresponds to the accuracy of the existing model. The new data correspond quite well with the model in the area of the existing open pit mine and in the crossing lineament, but not so well in the area east of the lineament. In this area east of the lineament a new model was created using both old and new data of the boreholes. The new model shows that the ore body is closer to the surface compared to the old model. Furthermore, the new model shows a distinct layering of an upper layer and a deeper layer. The upper layer contains less TiO2, while the deeper layer is similar to the ore in the existing open pit mine and in the crossing lineament. This information indicates that the ore in the eastern area is younger than the western area of the Tellnes ore body.

Olsen, Morten C. Nøst (B. Brattli)

The Spreading of Heavy Metals from the Ordot Landfill to Biotic Species and Sediments in Local Rivers on Guam. This thesis was undertaken to determine concentration of heavy metals in abiotic and biotic components in three rivers in close vicinity of the Ordot Landfill on the island of Guam in the Western Pacific Ocean. The Ordot Landfill is located near the village of Ordot in the central part of Guam, and has been operating as the island‟s primary landfill for industrial and municipal waste since the end of World War II. There are no early records documenting the nature and quantity of hazardous wastes disposed of at the site, but it is known that the landfill has been the recipient of a variety of uncontrolled wastes, including munitions, polychlorinated biphenyl (PCB)-contaminated oils from transformers and spent industrial and commercial chemicals. The Ordot Landfill lacks the conventional technology built in to modern day sanitary landfills, such as daily soil covers, impermeable membranes, and leachate collecting systems. As a result, several methane fires have occurred at the dump, which have required the temporary evacuation of nearby residents. Moreover, surface water idrainage and rainfall produce percolation of water through the trash prism and generates leachate streams down gradient of the landfill. The leachate is discharged into the Lonfit River, south of the landfill. Further south-east of the dump the Lonfit River merges with the Sigua River, which creates the Pago River. This river drains eastwards and emanates into the Pago Bay estuary on the eastern coast of Guam. The chemical composition of the discharged leachate and its impact on the local freshwater envisonment is largely unknown. The Ordot Landfill has been suspected for contaminating the local environment and has received attention from the United States Environmental Protective Agency (U.S. EPA) since the beginning of the 1980s. The Guam Department of Public Works (Guam DPW) which is responsible for the operations at the Ordot dump, received orders to cease the discharge of leachate to the Lonfit Riber already in 1986, but this has not been accomplished, and the discharge has continued to contemporary times. In 2003 a lawsuit filed by the U.S. Department of Justice, on behalf of the U.S. EPA in August 2002, mandated the Government of Guam to close the landfill by the year of 2007. Little is known of the fate of the pollutants which have been released to the local surface watershed throughout the years. Anually the freshwater rivers on Guam are also transporting large amounts of sediments from erosion and weathering processes of volcanic bedrock and soils to the shores around the southern part of the island. The impact of these sediments on the Pago Bay estuary and on the coral reef in Pago Bay is unknown. Little is also known of the levels of adsorbed heavy metals in the deposited sediments and the fate of these in the estuary. During the period of August 2003 – March 2004 river sediment samples and biotic representatives of the freshwater fauna and flora were collected from a total of 15 sites. The locations of the sites were in the leachate streams, and in the Lonfit, the Pago and Sigua Rivers. Sediments were collected from all 15 sites, while biotic species were not represented at all locations. All sampling locations are described in detail in the thesis. The dominant biotic groups examined were fish, crustaceans, gastropods and aquatic weeds. All samples analyzed were following conventional wet oxidation procedures in hot mineral acids. Nine elements (Ag, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were analyzed by the use of flame atomic absorption spectroscopy (AAS), while the tenth element (Hg) was analyzed with flameless cold vapor AAS. The findings of the analysis have been evaluated and discussed in relation to possible sources of input. A detailed comparative analysis with findings reported by other researches of related species from elsewhere have also been executed. In oveall, the sediment samples from the leachate streams showed increased levels of Fe, Mn, Zn and Hg compared to measured concentration in river sediments. However, when the findings in leachate and river sediments were compared to the established threshold values for the individual elements, Fe, Mn, Cr, Cu and Ni were found to be exceeding these values. Based on threshold values, most investigated river sites in the Lonfit and Pago Rivers could be described as moderately contaminated with respect to these elements. However, it was evident that the detected exceedances

41 Institutt for geologi og bergteknikk Hovedoppgaver 2004 downstream of the landfill were strongly related to the background levels of these elements represented in the local geology and soils, and not primarily results of leachate discharge from the Ordot dump. Based on the findings from upstream and downstream rivers sediments in the Lonfit River, and the findings in the neighboring Sigua River, it could not be established that the landfill was contributing to significantly increased levels of heavy metals in the sediments of the Pago and Lonfit Rivers with respect to the ten elements investigated. The analyzed specimens of fish and crustacerans did not exceed established food standards and guidance limits. These findings indicated that the levels of heavy metals in the investigated biotic species of fish and crustaceans are not in particular affected by the discharge of these ten metals from the Ordot Landfill, or from metals derived from the local geology and soils. The findings in gastropods indicated possible bioindicator potentials for Mn and Fe with Neritina Pulligera, and for Mn and Cu with Neritina variegata. However, these findings may also be a result of naturally occurring elements in the organism‟s biochemistry and the actual reason for increased levels of those trace elements remains uncertain after this study. The aquatic weeds, Hydrilla verticillata, collected from one Pago River site had Fe/Mn ratios equivalent to levels which would indicate Mn-toxicity and Fe deficiency. Interesting enough, samples of Hydrilla verticillata from a further downstream Pago site had healthy Fe/Mn ratios. Ecological and environmental observations are included in the present study, and discrepancies and uncertainties related to the research have been commented. Recommendations for future directions of continued research in the Lonfit and Pago Rivers and in Pago Bay have been suggested, and clean up alternatives related to the closure of the landfill are also presented.

Seim, Kai Inge (K.L. Sandvik)

Minimalisering av krominnhold i endelig ilmenittkonsentrat ved Titania A/S ved forbedret svakfelt magnet separasjon. Minimalisation of the chrome content of the final ilmenite concentrate by Titania A/S by improvements in low intensity magnetic separation. The objective of this thesis is to evaluate present and future use of low intensity magnetic separation to minimize the chromium content of the ilmenite product from the Norwegian mine Titania. Ilmenite is there mined from the world largest titanium deposit in solid rock. The deposit has however, a content of 2% magnetite which hold 0,8 – 1% chrome. Removal of magnetite is therefore important. The main goal has been to reduce the chrome in the concentrate by increasing the recovery of magnetite in the primary LIMS installation. Tests were done to pump part of the magnetite concentrate back to the primary separation stage. The hypothesis was that a higher magnetite loading on the separator would improve separation. The results were negative and showed that the content of magnetite in the non-magnetic discharge increased. Another point was to investigate if the magnetite in the gravitational concentrate could be reduced significantly by further magnetic separation. A pilot test separator was placed after the spirals which produce this con-centrate. The results were positive and demonstrated that the magnetic content could be reduced. As a part of a plan to improve the present flowsheet, a comparison of one Ø1200 counter-current separator with one con current was done. The result showed that the counter-current separator was equal or better than the con current. Microscopic investigations were done on the magnetite which passed through the magnetic field in the primary circuit. Mostly locked particles of magnetite were found, but liberated particles occurred. The magnetite that was found in the gravitational concentrate was mainly liberated magnetite which was unexpected.

Shrestha, Pawan K. (B. Nilsen)

Engineering geological analysis of underground structures at Middle Marsyangdi Hydroelectric Project, Nepal. Construction work for the Middle Marsyangdi project started in 2002 and is expected to be completed in 2006. Among the main underground excavations for the project are 3 large settling basins, each with width ~15 m, height ~ 30 m and length ~ 150 m, and a 5 km long headrace tunnel (the powerhouse is located on the surface). The bedrock in the area mainly consists of foliated quartzite, and the rock cover of the underground structures is relatively small. The purpose of this thesis has been to analyse the engineering geological aspects of the underground excavations of the project, with main emphasis on the large settling basins. Stability, cavern design and rock support requirement have be analysed with main emphasis on empirical analysis and numerical analysis based on the Phase2 FEM code.

42 Institutt for geologi og bergteknikk Hovedoppgaver 2004

Skjærpe, Ivar Martin (S.O. Johnsen)

Paleocen sand distribusjon på Sørvestlandet Høyden. Paleocene sand distribution on Sørvestlandet High. The Sørvestlandet High lies up from the Central Trough in the southern part of the Norwegian sector. Wells drilled in the area show that shales predominantly comprise the Paleocene interval. This is not surprising considering that these wells are mainly drilled on pre Paleocene stratigraphic traps, mainly salt induced. As these structural highs made out the Paleocene bathymetry in the area, possible turbidite sands have eluded these areas and most probably deposited in near by rim synclines and basins. The turbidite sand found in the Paleocene interval, in wells around the Gyda and Ula fields in the Central Trough could very well origin from the Norwegian continental shelf and not the East Shetland Platform and the Scottish Highlands as previously believed. Formation thickening up slope to the Sørvestlandet High, as well as obvious channel cuts are indications of this. It is possible, from this study, to be certain that the thickening on Sørvestlandet High is due to tm turbidites that are in connection with the ones found in the Central Trough. Seismic resolution, even on HFI reprocessed data, proved to low for convincing tracking up slope. Secondary migration is a key issue for the Sørvestlandet High to be a prosperous area as the Mandal formation in the Upper Jurassic interval is immature here. Hydrocarbons are thought to have migrated from the kitchen area in the Central Trough. There are at least two good possibilities for the migration through the Gretaceous and into Triassic sands. The extensive faulting on the graben flanks is one possibility. However, we have strong indications of sealing in at least one location. The other suggestion is migration through micro-fractures associated with the vast numbers of salt diapirs in the area. This provides a multitude of potential pathways for the hydrocarbons. The Depositional Models presented in the study reveals plausible distribution maps for Paleocene sands on Sørvestlandet High.

Tøndel, Tonje D. (S.O. Johnsen)

Stratigrafi og diagenese i Lisburnegruppen, Endicott Mountains, arktisk Alaska. Stratigraphy and Diagenesis of the Lisburne Group, Endicott Mountains, Arctic Alaska. The Lisburne Group in Brooks Range, northern Alaska makes up a thick sequence (> 400 m) of laterally extensive carbonate deposits. It apparently developed along a southward passive continental margin, on a subsiding carbonate ramp. The Lisburne Group records cyclic stratigraphic successions, alternating from open marine to restricted lagoon facies. Facies stacking pattern suggests that a northward transgression onlapped terrigenous deposits of the Endicott Group. The Wachsmuth Limestone is at least 300m thick and consists mainly of skeletal packstone and grainstone. The packstones and grainstones are poorly sorted, have a high abundance of disarticulated valves and moderate evidence of abrasion. The absence of carbonate mud indicates that most of deposition took place above wave base. The Alapah Limestone is finer-grained, consists of darker, more argillaceous mudstones and wackestones with a predominance of carbonate mud that indicates that most deposition took place below wave base. Several stages of diagenesis occurred in the limestones. The first is a void filling fabric followed by micritic rim, followed by syntaxial cement, which is considered to be the first phase of sparry calcite cementation. The second phase is a blocky calcite cement which completely obliterates the available pore space with subequant crystals that are coarser than the first-phase cement. Great dolomite concentrations are not common in the Lisburne Group of central Brooks Range. However, minor dolostone beds are seen. The dolomites are found both as matrix material and as replacement fabric, which result in crystalline rocks.

Westre, Kjetil (M.B.E. Mørk)

Overpalaeozoikum karbonatreservoargeologi med vekt på gzelintervallet på Finnmarksplattformen, Barentshavet. Upper Palaeozoic Carbonate reservoir geology focusing on the Gzhelian at the Finnmark Platform, Barents Sea

43 Institutt for geologi og bergteknikk Hovedoppgaver 2003

2003

Brekke, Even (B. Brattli)

Energiuttak fra borehull i fjell. Energy Extraction from Boreholes in Hard Rock.

Bye, Trine Røisland (E. Broch)

Storing of Water in Rock Caverns in Singapore. This thesis evaluates the potential for storing of drinking water in rock caverns in Singapore, and covers every aspect concerning cavern technology, i.e. planning, design and construction. The feasibility evaluation is primarily based on investigations carried out in the Bukit Timah Granite in an earlier feasibility study, and investigations in connection with an ammunition storage facility (UAF). These studies showed that the granite is a suitable material for cavern construction, which also was concluded from the earlier studies and the construction of the UAF. A total of 14 sites have been selected based on height requirements in three different rock formations; the Bukit Timah Granite, the Gombak Norite and the Jurong Formation. Detailed investigations in the Gombak Norite have been carried out, but available literature has however shown that the formation has similar properties as the Bukit Timah Granite. As for the Jurong Formation, the rock is competent for cavern development, but the costs will be higher. The technical feasibility, including planning, layout, design and cost are based on a typical facility storage with a storage volume of 112,000 m3. Cost estimations for both underground and above ground water facility are made, concluding that construction of underground caverns is preferable, especially considering the land premium that must be taken into consideration for an above ground water tank.

Cappelen, Paul Ingvard (K.L. Sandvik)

Tildekking av forurensede sdimenter. Capping of contaminated sediments. Sedimentation and bearing capacity of dredged material. Capping is a new method for treatment of contaminated sediments in Norway. The goal is to isolate contaminated material and hinder the spreading of heavy metals and organic pollution from the sediment to the water column. The contaminated sediment can be capped in situ or dredged and deposited at a more suitable location before capping. In Norway, where there are deep fjords with low concentration of oxygen at the seabed, the dredged sediments can be deposited and capped to greater depths. A sedimentation test was designed to investigate the degree of mixing between fine grained dredged sediments from Bjørvika in the Oslo Fjord and coarser capping material. Crushed limestone and shell sand sieved through 2 mm sieves were used for capping. The laboratory tests showed that the capping material covered the sediments with water contents up to 300-350 per cent. At higher water contents the limestone and shell sand settled partly or fully through the sediment slurry. The main trend was that the shell sand was retained at the sediment surface earlier than the limestone. The rate of consolidation increased when mainly limestone, but to some extent also the shell sand, was mixed with the contaminated sediments. This was due to interaction between clay particles in the sediment and calcium carbonate in the capping materials. The water content was higher when the capping material was added at an early stage of the consolidation process. This shows that increased consolidation rate leads to higher water content in the final product. A load test with a circular lead was developed to measure the bearing capacity and the shear strength of the soft Oslo Harbour sediments. Four tests were performed on sediments without capping, with a two centimetre cap of shell sand and with a mixture of shell sand and sediment. No particular difference was obtained in the experiments with only sediment and with the shell sand-sediment mixture. Typical shear strength values of approximately 0,05 kPa were found. Capping with two centimetre shell sand increased the shear strength dramatically. The results show that capping of sediments with coarser material increase the bearing capacity and stability of the contaminated sediments. Although the methods used in the experiments were successful, they do not reflect real fjord or harbour conditions, and further investigations are recommended to obtain better knowledge.

Chinh, Nguyen Huu (B. Nilsen)

Engineering Geological Analysis of Sesan3 Hydropower Project, Vietnam. The purpose of this thesis has been to carry out engineering geological analyses of the planned underground excavations for the SeSan3 Hydropower Project in Vietnam. Feasibility studies for SeSan3 have recently been carried

44 Institutt for geologi og bergteknikk Hovedoppgaver 2003 out by the Swedish consultant SWECO in co-operation with Vietnamese consultant PECC1. The planned project includes two approximately 80 m long and diameter 7 m lined headrace tunnels, an underground power house and 2 approximately 90 m long and diameter 7 m tailrace tunnels. Main emphasis have been placed on analysing the proposed tunnel alignments and power house cavern location and orientation, the power house design and geometry and the requirement/design of support and lining. Numerical modelling based on FLAC-3D represents a major part of the analyses. Based on the analyses, recommendations have been made concerning design and further

Dahl, Kjetil (E. Broch)

Vurdering av sammenhenger mellom bergartsparametere og injeksjon ved bygging av T-banetunnel. Evaluation of the Correlations between Rock Mass Properties and Grouting during Tunnel Construction. Possible correlations between rock mass properties, consumption of grouting material and obtained water tightness for the subway tunnel between Ullevål stadion and Nydalen in Oslo have been studied. This is done as a parametre study of the different factors in the Q-system and their relevans for propagation and obtained tightness for standard grouting cements and one type of micro cement with varying water/cement – ratios and grout pressure. It is concluded that neither the Q-value itself nor any of the included factors can give a reasonably precise prognosis for the grout take. The RQD seems to be the one single factor that gives the best correlation.

Gjeldokk, Tore (B. Brattli)

Bly i overflatejord og elvesedimenter. Lead in Surface Soil and River Sediments.

Gjerde, Arild (B. Nilsen / Public Roads Administration)

Rogfast-tunnelen, ingeniørgeologisk analyse av trasé/linjeføring og tverrsnittsutforming. The Rogfast Tunnel, Engineering Geological Analysis of Alignment and Geometry. For the Rogfast tunnel, a planned 24 km long subsea road tunnel under the Boknafjord in Southwest Norway, engineering geological analyses of the alignment and geometry have been carried out. If built, this tunnel, going down to a maximum depth below the sea level of approximately 360 meters, will be the longest and deepest subsea road tunnel in the world. The rock mass, consisting of Paleozoic phyllite and greenstone and Precambrian granitic gneiss, has been characterized based on available background material, site visits and laboratory testing. As part of the analyses, numerical modelling based on Phase2 has been carried out. It is concluded that the planned tunnel project is feasible with a minimum rock cover of 40-50 meters. For final design of alignment and geometry, more ground investigations are required.

Godøy, Olaug (K.L. Sandvik)

Tildekking av forurensede sedimenter, mobilitet til tungmetaller og PAH. Capping of contaminated sediments, mobility of heavy metals and PAH. Lately, environmental problems related to contaminated seabed sediments in Norwegian fjords have come to focus. Over a long period, environmental toxic spills have caused considerable hazards along the coastline in some areas, hence the sediments are very contaminated. Initiatives for preventing further spreading of pollution must be implemented. An economically effective alternative is to deposit the contaminated sediments under controlled conditions in the sea, and cover it with clean capping materials. An interaction between an anoxic sediment and an oxic capping material can cause chemical reactions leading to degradation of redox sensitive minerals (like oxides and FeSx), which can further lead to leaking of environmental toxics bound to minerals. On the other hand, a capping material can have positive effects regarding adsorption of heavy metals PAH. Leak- and oedometer tests have been performed to try quantifying leaking of redox sensitive metals, heavy metals and PAH from sediments, different capping materials, and a mix of these. The purpose of the test is to find an optimal design for the initiative due to type of capping material and thickness, even if it can not be concluded from the tests alone. The leak- and oedometer tests indicate that capping of contaminated sediments is a positive initiative in relation of leaking environmental toxics. A capping layer of only 1 cm thickness manages to keep the particles within the sediments, and only allows interstitial water to pass through. This result is positive as environmental toxics that are bound to particles do not disperse. The leaking of PAH is lower with an interaction between sediments and capping material than without. Some of the heavy metal leaking comes from the capping material itself. This specially applies immediately after

45 Institutt for geologi og bergteknikk Hovedoppgaver 2003 capping. Nevertheless, a capping material will presumably have a positive effect regarding adsorbing the heavy metals from the sediments. Both limestone and gneiss are good alternatives as capping materials, though the total leaking from limestone is less than from gneiss.

Groth, Janne Bakke (B. Brattli)

Kjemisk nedbrytning av resirkulert tilslag. Chemical Degradation of Recycled Aggregate. This Master of Science thesis is a part of a project aiming to evaluate chemical deterioration of recycled aggregate exposed to flowing water. The aim of the thesis is to do the necessary preparations to investigate the mechanical properties of recycled aggregate due to chemical deterioration. Accordingly, national and international literature on this subject is being studied. The deterioration process is explained, and the most important effects of chemical deterioration are described. Further, the recycled aggregate is documented by Norwegian and European Standard tests. The results of the tests show that the recycled aggregate satisfy the demands set by “Kontrollrådet for betongprodukter”, but the recycled aggregate consists of smaller particles than the demand for instance in Norwegian Standard NS 3420 H. To investigate the mechanical properties of the recycled aggregate it is necessary to build a full-scale experiment, but further testing in advance is demanded in order to clarify unknown factors, such as speed of reaction. The results of these tests will provide useful information about replacement of water, acid consumption and temperature dependence. The full-scale experiment is an accelerated laboratory experiment, and the effects of the accelerated exposure are estimated. The main principal for the full-scale experiment is that the recycled aggregate is being put in columns and exposed to flowing water of different qualities. The project will last for approximately 2 years. There will be taken water samples of the solution that has run through the recycled aggregate. The water samples will show the leaching from the recycled aggregate, but they will not describe the mechanical properties of the recycled aggregate. The water samples, however, will indicate the deterioration of the recycled aggregate. There will also be performed tests to document the properties of the recycled aggregate, as mechanical strength, density, water absorption and portion cement paste. These tests will show how the recycled aggregate reacts after being exposed to water. The tests are performed every 6. month, by removing one of the columns. The full-scale is designed and built during the work with the Master of Science thesis. There is also proposed a plan for sample procedures and routines for the running of the full-scale experiment.

Gudmundsson, Hlynur (B. Nilsen / Mika AS)

Analyse av utført injeksjon i Skaugumtunnelen. Analysis of performed injectiont in the Skaugum tunnel. For the 104 m2/3.6 km long Skaugum railway tunnel, presently under excavation between Sandvika and Asker near Oslo, engineering geological aspects of grouting have been analysed. The extent of grouting in the tunnel has been mapped and described, and as-built results have been compared with pre-construction prognoses. Main emphasis has been placed on discussing the extent and effect of grouting versus the engineering geological conditions. Correlations between grouting results and classification parameters such as RQD and Q have also been discussed, and the usefulness of measurement while drilling (MWD) has been evaluated. Due to the very strict leakage criteria (maximum permissible inflow 4-16 l / min x 100 m), systematic grouting has been performed in the entire tunnel. It is concluded that the grouting has been mainly successful. To a great extent, this is believed to be result of the fact that grouting has been highly prioritized.

Hagen, Kjersti Fuglseth (B. Nilsen / Public Roads Administration)

Analyse av utført tettings-injeksjon i Lunner tunnelen. Analysis of grouting carried out at the Lunner tunnel. For the 3.8 km long Lunner road tunnel, excavated as part of new Rv. 35 in Oppland (Southeastern Norway), and completed in October 2002, the effect of grouting has been analysed. Particular emphasis has been placed on discussing correlations between engineering geological conditions and extent /effect of grouting, the significance of grouting technique on grouting result, and the potential correlation between inflow in probe drillholes and the grout requirement. The extent of grouting carried out it the tunnel turned out to be considerably higher than originally estimated. It is concluded that to a great extent this is believed to be due to the fact that the joints in the rock mass were

46 Institutt for geologi og bergteknikk Hovedoppgaver 2003 more open than expected. Finally, a comparison has been made between the grout requirement in the Lunner tunnel and the nearby Hagan road tunnel, which was excavated with a considerable smaller rock cover than the Lunner tunnel.

Haltbaakk, Jorunn (K.L. Sandvik)

Organiske miljøgifter (musk og legemidler) i sigevann fra kommunale fyllinger - adsorpsjon og nedbrytning i sandig akvifer under ulike redoksforhold. Organic compounds (musks and pharmaceuticals) in leachate from a municipal landfill – adsorption and degradation in a sandy aquifer under different redox conditions. This thesis is a part of Jordforsks ongoing Strategical Institute Programme (SIP): “Binding and mobilisation of organic pollutants in soil and sediments; the importance for remediation processes”. The main purpose for this programme is to increase the knowledge around organic pollutants and how to reduce the negative effects different compounds has on the environment. These compounds can cause damage to human beings and the environment. One of the purposes of this programme is to study emission of organic from municipal landfills. The aim of this study was to investigate degradation and adsorption of a few organic pollutants from municipal landfills. To investigate these pollutants in a way where the results would also be valid in the field, and particularly in sandy aquifer, pilot model was developed. The model consisted of eight columns of stainless steel. The columns were connected to a reservoir of contaminated leachate which was spiked with the pharmaceutical Ipuprofen and the polycyclic musk compounds Tonalide ® and Galaxolide ®. These particular compounds were used as they have been given increased attention recent years. Research show that they are potentially hazardous and have a negative effect on the environment, the pollution being caused by sources such as leachates and disposal of drugs in waste landfills. The laboratory columns contained aquifer materials from a glacifluvial deposit nearby the actual landfill where the leachate was collected and is of same quality as the sandy aquifer beneath the landfill. A microbial inoculum was added to all columns to obtain similar hydraulic conditions. After some days 4 of the 8 columns were sterilized by y-radiation to obtain different conditions in the columns. The sterile columns were used to investigate adsorption of the added compounds while the non-sterile columns were used to investigate degradation. The columns were operated under upflow conditions (flow rate 0,87 ml/min) for 18 days. 200 litres anaerobic conditions in a nitrogen-tent and send to analysis of different parameters. In addition to degradation and 2+/3+ 2- + adsorption of the organic compounds focus was set on concentration of Fe , SO4 and NH4 in the columns. pH, conductivity and redox conditions was monitored. Potassium bromide was used as a tracer. The results are varying, but there are significant differences between the sterile and the non-sterile columns. Microorganisms occur naturally in leachate, and it can be concluded that both adsorption and degradation occurs in a contaminant plume even in a sandy aquifer. The retardation of a sandy aquifer is normally low, and the results show different rates in leaching for the sterile and non-sterile. The degradation of the organic compounds is to a large extent caused by microbial processes. It can be concluded that the results from this pilot model are valid in the field. Adsorption and particularly microbial degradation will occur in a sandy aquifer.

Hammer, Erik (S.O. Johnsen)

En 3D seismisk undersøkelse av den sen Pliocene til Pleistocene prograderende kilen utenfor Lofoten. A 3D-seismic stydy of the Late Pliocene to Pleistocene prograding wedge off Lofoten. The study is mainly based on interpretation of 3D seismic data from the Røstbanken area, North-Norway. The main aim has been to interpret surface morphology and seismic stratigraphy in order to elucidate the Late Pliocene to Pleistocene evolution in this area. Eleven horizons were identified within the Pliocene – Pleistocene section. Hey display various surface features including, icebrtg plough marks, lineations, mega-scale glacial lineations, pock marks, recessional moraines, channels and glaciotectonic depressions. Several bright spots have also been identified, indicating the presence of gas in some areas. The horizons include the sea floor reflection in addition to ten buried horizons (A-J). The buried horizons represent upper bounding surfaces of Units (aA-jJ) indicating a westward progradation direction for Units aA and bB, and a shift to a general south-westward direction for the shallower Units cC to jJ are interpreted to have been deposited during advances of a local ice cap covering the Lofoten area. This imlies that the Lofoten area was an important source area during deposition of Units cC to jJ. The southernmost part of the study area was heavily influenced by the Trænadjupet Ice Stream during the last glacial maximum as indicated by the presence of mega-scale glacial lineations in this area. Onset of the final deglaciation

47 Institutt for geologi og bergteknikk Hovedoppgaver 2003 occurred around 15-14 14C ka BP and three larger ice sheet re-advances are recognized during the general retreat of the ice front.

Haug, Tove Anette (B. Brattli)

Prøvepumping av løsmassebrønner for vurdering av grunnvannsuttak til smoltanlegg ved Røssåa. Terstpumping of wells in Glacial Deposits with Evaluation of Groundwater Extraction for a Fish Farm by the Stream Røssåa. Two groundwater wells have been established by the stream Røssåa in a glaciofluvial fan that is mainly composed by sand and gravel. The wells will, together with water from Røssåa, cover the need of water for a fish farm owned by Statkraft. The desired maximum yield is set to 0,075 m3/s. Three pumping tests were conducted. One step-test in each well and in addition to this, well A was pumped with a constant yield for seven days. There were also performed size analyses of the formation samples. The drawdown is influenced by the sloping water table with a gradient around 0,04, the partial penetration and the upward movement of the groundwater in the lower part of the fan. The coefficient of transmissivity, T1, for the step-tests, almost equals the result from the grain size analysis. T1 is probably reflecting the hydraulic properties of the soil that surrounds the wells. After a couple of hours of pumping well A, the drawdown curve changed path. It looked like the water table had met a negative boundary. The probable cause of this is when a well is surrounded by a sloping water table the cone of depression will not be the symmetrical. So when the well is pumped over a longer period, the area, which water is converging towards the well, will decrease. The coefficient of transmissivity, T2, which was calculated from the last part of the curve, will not be the correct one, but it will be used as an apparent transmissivity, which includes the hydrogeologic conditions of the aquifer when it is pumped over a long period of time. The capacities of the wells are high enough to cover the requirement of fish farm. By examining the well performance of each well, the drawdown that occurred under the pumping tests and the theoretical drawdown during maximum withdrawal, there seems to be two alternatives to the distribution of the extraction between the wells: 30% from well A and 70% from well B or just use well B until the requirement exceeds the capacity of well B, and then start pumping well A. One water sample from each well that was taken during the pumping tests has. These samples have been analyzed for common cations and anions. Some samples taken in 2002 have also been analyzed. The groundwater is suitable both as drinking water and for fish farming, but the content of zinc exceeded the standard of secure health values for fish. It is uncertain if the source of the zinc is the deposit or the equipment used in the wells and under the tests. Further analyses of the water are therefore necessary.

T2 has been used to consider the effects of the ground water withdrawal. Neither settlement of the soil nor saltwater interference should be a problem, but the water supplies for the locals will decrease. It is difficult to determine whether the supply will go dry or just decrease. By using the measured drawdown and calculations using Theis, Copper & Jacob and Neumans method, some of the assumptions are not fulfilled. As a consequence of not following the assumptions, the results from the calculations are just approximate. To achieve a result that is more accurate, it is necessary to perform pumping tests over a longer period of time. Then it is possible to get knowledge about variations over a year. With proper software, which can take into account all restrictions in the deposit, it is also possible to make better calculations.

Hopland, Knut Martin (K.L. Sandvik)

Metodeutvikling for talkoppredning ved magnetseparasjon. Development of Processes for Talc Benefication. This report deals with 6 different local samples from a resource of talcrich steatite located in the northern part of Norway. These steatites contain approximately 3 – 5% oxides, among these magnetite is in majority. This mineral is not wanted when it comes to benefication of talc products, and the report touches the problems concerning the removing of this mineral. The investigations performed include crushing, sieving and magnetic separation using permroll separators. The focus on the performance of the separators and the possibilities of regulating parameters are also a main part of the report, as well as a thorough measurement of the magnetic induction. Results show that the 6 samples have many equalities, but also differences that lead to a variation in benefication. Complete results of benefication for all samples and their different fractions, together with a microscopy report from NGU, where the mineralogy is neatly presented are also included.

48 Institutt for geologi og bergteknikk Hovedoppgaver 2003

Under influence of large magnetic induction, the benefication decreases, and the ideal induction for these samples proved to be in the amount of 0,426 tesla. Mass balance through the whole benefication process shows that the amount of fine material should be limited, cause the loss of these small size particles is relatively big for parts of the process. This should also be considered if a full scale production is to be launched. The quality of the products from the permroll separation turned out to be lower than 0,1 weight percent magnetite for the optimal parameters.

Humstad, Tore (E. Broch)

Geotechnical evaluation of possible road tunnel project in Nuuk, West Greenland. The geology in the area relevant for a possible southwards extension of Nuuk, in West Greenland, has been investigated with respect to tunnelling. The main focus was given to the prospective Siorarsiorfik tunnel. This tunnel will be excavated through the tonalitic and granodioritic Nuuk gneisses, which are observed to have very high compressive strength of 130 – 170 MPa, medium drillability, and sound velocities of 5100 m/s. Observed Q values of 4.5 - 48 in the actual area, suggest rock mass with fair to very good sufficiency for tunnelling. Three alignments for the Siorarsiorfik tunnel are suggested at lengths varying from 600 to 1100 m. The constructional costs of these are estimated to be DKK 30 – 40 millions, that is DKK 34000 – 46000 per meter tunnel. Two different profiles are suggested. One of them includes extra space for a biking and walking path. The jointing in the investigated rock mss strongly depends on the NNE-SSW foliation of the rock. The strike of a major joint direction is parallel to this foliation. Due to folding of the rock mass, these joint planes dip at various angles and directions. A WNW-ESE joint direction is also prominent. However, the jointing is in general limited, as they divide the rock mass into 1 - 10 m3 blocks. Montmorillonite were found in the Nuussuaq tunnel, and is also believed to exist elsewhere in the area. There exist few major weakness zones in the area. Some scattered Quaternary deposits exist. None of these are believed to contain permafrost, despite the high air freezing indices. Locations for some entrances appropriate for subsea tunnels, are also found. The jointing was measured and, the rock quality of these is good to very good, according to the Q system. A seismic reflection line at the outlet of the Ameralik fjord, suggest the presence of a major lodgement moraine at the eastern side of the fjord threshold, and a terminal moraine at the western side. The thickness of these extends to approximately 50 m. Overlying clay deposits are probably less extensive. The depth of the bedrock table of the threshold, is believed smallest at the easternmost of the strait 110 – 130 m below sea level.

Huque, Asma (S. Lippard)

Sequence Stratigraphy of a Part of the Bengal Basin with Some Implications for the Hydrocarbon Potentiality. A sequence stratigraphic analysis of a part of the Bengal Basin is made on two regional seismic sections collected from BOGMC. Four megasequences are recognized related to large scale basin development. Seventeen sequences are defined by unconformities. Six representative seismic facies are identified and used for depositional environment interpretation. Lateral facies change with the relative position and genetic systems tracts of the sequences and parasequence sets. They also vary with the presence or absence of parasequence sets within the same sequence. A relative sea-level curve prepared in this study shows general regression of sea-level in the Cenozoic which is similar with the published „global sea-level curve‟. The present day Bengal Deep-sea Fan is a detached fan system from the prograding on shelf delta system. Paleochannels through the mid-shelf and near the slope indicate that they could have been the tributaries of „the Swatch of No Ground‟ in the past. Change of shelf edge delta setting in to a low angle siliciclastic ramp setting occurred in the Oligocene-Miocene time with relation to the uplift of the Himalaya. Before the Himalayan orogeny the sediment source area was the Indian craton, after the Oligocene numerous rivers from the rising mountain contributed sediments in the Bengal Basin. The present day shelf break at about 250 km away from the shoreline could have been formed between late Miocene to early Quaternary. Potential stratigraphic traps are the topsets of lowstand deltas, offlap break of highstand deltas, lowstand wedges, channel-fill sands and the basin floor fans.

Ingimarsson, Atli Karl (E. Broch)

Ingeniørgeologisk prognose for Nordoyatunnilin på Færøyene. Geotechnical Engineering Prognosis for Nordoyatunnilin in the Faeroe Islands

49 Institutt for geologi og bergteknikk Hovedoppgaver 2003

The rough topography of the Faeroe Islands is probably the main reason for the relative high rate of hard rock tunnel excavation in these islands for the last forty years. The geology of the islands is dominated by extrusive basalt rocks, which are 50 - 55 million years old, constituting a remarkably regular deposition with a moderate number of recorded tectonic events. The first subsea tunnel on the islands, Vágatunnilin, was excavated during 2000 - 2002, and another one, the 6.2 km Nordoyatunnilin, is currently being planned. A geotechnical engineering prognosis is made for Nordoyatunnilin, based on the experience from earlier tunnelling in the Faeroe Islands and similar rocks in Iceland. Field observations in numerous tunnels in the Faeroe Islands indicate, in general, a good rock quality for tunnelling in that type of rock mass, and necessary rock support is minimal. As a subsea tunnel in corresponding competent rock mass of compound lava flows, Vágatunnilin is providing the most important experience for this prognosis. The engineering geological preinvestigations for Vágatunnilin, and the resulting prognosis, are evaluated and compared to the later performed safety installations in the tunnel. The Q system, which is used for rock mass classification and design of the rock support, is assumed to be not fully suitable for the basalts. Therefore, it is only used to make instructive guidelines for an active design of necessary rock supports in Nordoyatunnilin. During the excavation, the decisions about the rock support will have to be based on the local geology, for each location in the tunnel. These decisions will further have to be based on an earlier experience. So are the predicted amounts of rock support for the tunnel as well, with the results from the engineering geological preliminary investigations taken into account. The tunnel will be excavated by drilling and blasting. The average progress is estimated to be 45 - 50 m/week on each working face. The tunnel project is expected to be accomplished with geotechnical project class 3 according to the Norwegian Standard NS 3480. The rock support is expected to consist of only scaling, bolts and shotcrete, with an average extent of respectively 12 m2, 3.2 bolts and 0.7 m3 per meter tunnel. Ahead of the face, probe drilling shall be used to expose possible weak rocks and water leaking zones. Only small and sporadic leakage is expected to occur in most of the tunnel, but that will not eliminate requirements for pregrouting. Based on demands for a maximum water leakage into the tunnel to be 300 l/min/km, the applied grouting mass is in average calculated to be 170 kg per meter tunnel. The grouting mass will mostly consist of rapid cement, but micro-cements should probably be used also. About 70 000 m2 of the tunnel surface is expected to be covered with mats of fireproof PE-lining for water sealing.

Jacobsen, Kine (K. Rokoengen)

Skråningsstabilitet og nedbørsutløste jordras langs Dovrebanen, Region Nord. Slope stability and precipitation induced landslides along the railways of Dovrebanen. The purpose of Jernbaneverket‟s (The Norwegian National Rail Administration) emergency plan is to prevent damages and accidents on trains caused by landslides during heavy rainfall. Landslides are often initiated during heavy rainfall and/or snowmelt. Data from recorded landslides along the railways and precipitation data from the Norwegian Meteorological Institute (DNMI) have been investigated with the intention of finding associations between precipitation and landslides and to evaluate variations in Norway. The data show partial associations, but no precise correlation can be identified from the available data. Studies of precipitation that have not resulted in landslides seem to support the assumption that a higher relative precipitation is required to get risk of landslide in areas with a low annual rainfall. In areas where the average annual rainfall is less than 600 mm, the threshold value might be increased beyond the 8% of the current emergency plan. The data further indicates that the threshold value may be increased to between 10 and 12% in areas with less than a 400 mm average annual rainfall. Draining and the use of vegetation are both alternative initiatives to the emergency plan. Draining reduces the risk of landslides by directing the surface water to trenches. Vegetation contributes to a reduction in erosion on slopes and reduces the groundwater level and pore pressure. A selection of vegetation with a variety of root systems is the most efficient way to attain an optimal binding effect within the soil. Alder, poplar, oak and elm are species that are recommended along the most vulnerable parts of the Dovrebanen railway.

Johnsen, Iselin (T. Myran)

Kvernede bildeke som gjenbruksmateriale i støyvoller. Shedded tyres as recovered material in sound barriers.

Knudsmoen, Hanne (B. Nilsen / National Rail Administration)

Analyse av nytteverdien av ingeniørgeologiske undersøkelser for Jong-Asker-tunnelene. Analysis of the usefulness of engineering geological investigations for the Jong-Asker tunnels.

50 Institutt for geologi og bergteknikk Hovedoppgaver 2003

For the 104 m2 and 3.6/2.7 km long Jong-Asker railway tunnels, presently under excavation just West of Oslo, the usefulness of engineering geological investigations has been analysed. The pre-construction investigations for this tunnel project have been extensive, and during excavation, thorough mapping is carried out by engineering geologists. The correlations between investigation results and as-built geological conditions are discussed, as well as the practical use of pre-investigations results and the value of supplementary investigation during excavation. Due to the very strict leakage criteria of these tunnels (maximum permissible inflow 4-16 l / min x 100 m), particular emphasis in this thesis has been placed on investigations for prognosticating water inflow. It is concluded that the prognoses based on pre-investigations have correlated mainly quite well with the actual conditions.

Kvalheim, Endre/Mork, Håkon (A. Myrvang / K. Nielsen)

Brytningsmetode og økonomiske beregninger for Engebøfjellet. Mining plans and costs connected to the eclogite deposit Engebøfjellet.

Lillebø, Trym Eirik (K.L. Sandvik)

Miljøpåvirkninger og kostnader ved boring på Snøhvitfeltet. Cost and Environmental Impact of Drilling at the Snøhvit Field.

Myhr, Kent Are (T. Myran)

Støv i arbeidsmiljø og ytre miljø i Svea. Dust in Working Atmosphere Environment in Svea.

Odong, Robert (E. Broch)

Bujagali Hydroelectric Power Project in Uganda - A Case for Tunnelling Option. The thesis is aimed at analysing the Bujagali hydroelectric project on the river Nile by pulling it back to prefeasibility level. Four tunnels each 175 m2, measuring 6 km long are proposed as the alternative arrangement to offset the related impacts. Four equal size large Kaplan turbines of gross capacity of 266 MW are housed in shallow seated powerhouse cavern sited just below the intake of gross head 26.1 m at mean flow of 1200 m3/s giving a maximum head loss of 1.3 m. The maximum discharge in each turbine is 300 m3/s, leaving adequate remedial flow over the 10 m high concrete weir with only 75 m of crest length that also acts as a broad crested spillway for 10,000 yr flood of 4500 m3/s. Since the operation optimization is beyond the scope of this thesis, the total energy production per year is assumed to be in excess of 1500 GWh. On a very conservative basis, the civil cost is found to be USD 130 million which is 24% of the USD 550 million proposed by the private developer. The cavern/tunnels are designed based on the Norwegian tunnelling practice which emphasizes the importance of rock stress, weakness zones, water permeability and joint structures as factors to predict stability problems in the underground structures. Bieniawski‟s RMR method of quantitative classification was ued as an empirical tool for estimating the rock support requirement in the cavern and tunnels. A fundamental assumption based on extrapolation is made upon the known set of drillholes to predict the geological conditions in the vicinity. For the little rock cover, existence of even moderate horizontal stress would greatly improve the technical feasibility of the project. Recommendation is made for further core drilling along the suggested tunnel and cavern alignment with the aim of establishing precise rock cover and rock stress sizes and directions.

Ringdal, Anne-Christin K (S.O. Johnsen)

En integrert rapport på kanalsystemer An integrated report on channel systems During last decades more and more attention has been brought to channel systems as their potential as reservoirs has become evident. The Ainsa area is probably one of the most studied outcrops in Europe and thus many opinions of the area has formed through time. It has been studied for decades by some of the worlds most dedicated sedimentologists with channels and channel related features as their field of interest. On the other hand, in the area of Block 25 offshore Angola the explorations have just started. In this study focus has been placed on the Quarry outcrop just south of the town of Ainsa located in the South-Eastern Pyrenees and on a channel system situated in the North-Eastern corner of Block 25, offshore Angola. The two channel systems that have been investigated are very different in size, but the geologic setting of the areas in which the systems are located have some similarities.

51 Institutt for geologi og bergteknikk Hovedoppgaver 2003

The study of the channel systems is based on data gathered through field work and seismic data interpretation.

Raaness, Agnes M. (T. Malvik)

Mineralbalansen i prosessanlegget til North Cape Minerals på Stjernøy. The Mineral balance at the Processing Plant of North Cape Minerals at Stjernøy.

Sharma, Bishnu Prasad (E. Broch)

Squeezing Assessment for the Melamchi Water Supply Tunnel. The proposed Melamchi Water Supply Project (MWSP) in Nepal includes a 26.3 km long water supply tunnel in metamorphic rocks, mainly migmatites, gneisses, quartzites and schists. The rocks in the Himalayas are generally weak, highly jointed, faulted, folded and tectonically disturbed. The overburden in the tunnel varies from about 75 m to about 1185 m. The main question for this thesis is an assessment for predicting squeezing conditions in Melamchi tunnel. The magnitude of tunnel convergence (% strain), and the extent of the yielding zone around the tunnel are estimated by using close form solution and Hoek-Marinos (2000) method. Both methods are developed for circular tunnel in hydrostatic stress conditions (i.e. stress ratio, k=1). However, Hoek-Marinos approach is applied for different in-situ stress conditions. Since the stress conditions are not known, the percentage strain and the plastic zone radius are calculated for different values of k for instance 1.25, 1.5, 2 etc. A brief discussion about estimating the rock mass properties is done. For the analysis, the rock mass properties are estimated by using software „RocLab‟. The degree of squeezing is estimated for various sections in the tunnel. Empirical approach is also used to identify the squeezing conditions and a stability factor approach is used to define the degree of squeezing. Later, the sections showing the highest % strains and the yielding zone are brought into numerical modelling for further analysis. Phase2 is chosen as an appropriate numerical code for the problem. The models are run for different scenarios with varying input parameters to see the effect on principal stresses, strength factors and deformations for unsupported tunnel. The parametric study involves the different values of k, GSI, residual m and s parameters and dilation angles. One of the models is run by adding rock supports and the results are observed and compared with the results from unsupported conditions. The results from all methods including Phase2 are summarised and compared. It is found that the results from Hoek-Marinos method are very close to the Phase2 results. Finally, a brief discussion on monitoring methods is given, in conjunction with a short description of a case study. Some conclusions and the recommendations are made based on this study.

Solberg, Inger-Lise (K. Rokoengen)

Geologisk utvikling og stabilitet langs Mortenelva i Målselvdalen, Troms. Geological development and stability along the Mortenelva river in the Målselv valley, Troms. The Målselv valley lies 30 – 60 km proximal to the Younger Dryas ice marginal deposits in Bakkejord (Outer Malangen). During the deglaciation large volumes of sediment were deposited in the Målselv valley. Glaciomarine and glaciofluvial deposits represent the largest input, but large amounts of fluvial and marine sediments are also recorded. Fluvial erosion and landslides have formed the terrain along the Målselv river. Many of the landslides are quick-clay landslides. Three old landslides occurring in the central part of the Målselv valley have been dated to the period 2 – 5 ka BP. Mortenelva is a tributary to the Målselv river. Mortenelva meanders in the border area between a sand terrace in the east deposited during falling sea level, and an area of clay on the western side of the valley. Datings, sediment logging, drillings and investigations with GPR provide an indication as to how the sediments were deposited in the area. In 2000 there was a small landslide in the Mortenelva river. In the following year there was a larger landslide exactly in the same place. Stability calculations show that the area was not safe even before the initial landslide in 2000. What triggered the landslides can be a combination of different factors, but the most important factor was probably erosion by the river. In addition to these two landslides, three others have been reported during the last few years. This particular area is therefore the most active landslide area in the Målselv valley. NVE has constructed 10 protection installations against erosion along the Målselv river, but none has been built along the Mortenelva river. The risk for new landslides along Mortenelva is probably so great that it is recommended not to carry out any construction work near the river.

52 Institutt for geologi og bergteknikk Hovedoppgaver 2003

Stensland, Kjersti (B. Brattli)

Laboratoriestudium av kulemøllemetoden. A Laboratory Evaluation of the Ball Mill Method.

Unsgård, Guro (T. Myran)

Radioaktivitet fra pukk brukt som bygningsmateriale. Radioactivity from aggregate used as building materials. Radon is a radioactive gas that can cause lung cancer at high concentrations. The levels of radon in Norwegian, Swedish and Finnish dwellings are higher than average, much due to the geological conditions in these Nordic countries. Alum shale, granite, and granite gneiss are rocks that contain high levels of naturally radioactive isotopes. These are all rocks found in great quantities in the Norwegian bedrock, and have a widespread use as aggregates. Radioactivity from aggregates used as building materials are given much attention because of an increasing awareness of the health hazard caused by radon. The opinions differ on what will be the best way of reducing this hazard. Some countries have introduced regulations controlling the content of radionuclides in building materials, which are too strict for Norwegian aggregates to pass. Other take a different approach, focusing on the construction of new dwellings rather than the contents of the building materials. Inexpensive preventive measures can be taken that are likely to reduce the indoor concentration of radon to an acceptable level. |A procedure for documenting the radioactive content in aggregates is needed, in order to face the increasing requirements. This procedure would have to be able to separate the radiation from the radionuclides uranium, thorium and potassium. Analyzing samples of aggregate in a laboratory is one way of determining radioactive content. Another and better way would be to perform measurements in the field. This would capture local variations that are bound to occur, as both uranium and thorium are present only in very small amounts in the natural environment and are subject to irregular distribution.

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2002

Abedin, Mobinul (S. Lippard)

Regional Seismic Interpretation of the Northern North Sea. This thesis contains the result from seismic interpretation study of the Norwegian sector of the northern North Sea. The main objective of the study is to interpret the Base Cretaceous Unconformity. A total of twenty 2D lines from three datasets have been selected for seismic interpretation. Using Landmark software, the 2D lines have been interpreted and the structural nature of the area has been observed in the whole section. Occurrence of a regional unconformity between the intervals helps to distinguish the syn-rift and post-rift sediments. The study area is bounded by a north-south trending fault zone known as the Øygarden Fault Complex to the east. The western part is occupied by platform and terraces. A deep trough observed to the northeast is the Sogn Graben. The fault bounded high observed in the north is the Tampen Spur. Another trough observed to the nothwest is the Møre Basin. The southeast part is characterized by a high known as the Horda Platform. The Viking Graben is extended from northeast to southwest crosses all the lines. A large number of fields viz. Hild, Barge, Huldra, Troll, Gullfaks, Murichon Osberg are placed within the study area which are observed at highs of the different lines. Structural maps were made based on the average velocity for the Base Cretaceous.

Ahmed, Newaz Khalis (S. Lippard)

Sequence stratigraphic analysis of the Mid-Norwegian Continental Shelf. Five sequence stratigraphic sequences (I-V) are defined. Sequence I seems to be a shelf or passive basin filling in calm water environment together with continuous subsidence in pre-Cretaceous time. A shelf wide erosional event then took place. Sequence II represents a highstand deposit at the lower part and lowstand of sea-level during the deposition of Unit C followed by layers of progradational parasequence sets with complex sigmoid-oblique configuration providing deposition on a wider shelf in the Cretaceous. Sequence III started with a shelf margin delta progradation sequence at the innershelf edge in the Palaeocene, a sharp change in depositional environment occurred from a broad shallow subsiding continental shelf to a deltaic setting. Within this shelf margin deltaic sequence, a prograding parasequence set is separated from a retrogradational parasequence set by an intra Palaeocene subaerial unconformity on the basin flank. The upper part of the Sequence III is a product of a relative lowstand of sea level as a shelf delta progradation through the mid to outer shelf during the Eocene. The older part of Sequence IV shows a lower part of delta front and prodelta parts are preserved only, which has formed during a high stand of sea-level in the Oligocene. Miocene sediments are missing here. The younger part of Sequence IV represents different pulses of regressive deposition on the inner to mid- shelf and is a combination of Pliocene-Pleistocene sediments. Sequence V is entirely Holocene and deposited in a shelf- wide sequence evident by inner shelf scouring and near shore channel filling. Highstand sequences are well preserved on the northeastern part of the study area. Basin margins along the shoreline were affected by uplift before the deposition of Palaeocene strata while middle part is more uplifted after the Eocene time. Holocene sediments are found just above the Eocene strata, the entire Sequence IV and part of the Eocene sediments are eroded from the middle part.

Aryeetey, Michael N.A. (S.O. Johnsen)

Diagenetic evolution of the Nordkapp Basin. Diagenetisk utvikling i Norkappbassenget. Cores from seven wells within the Nordkapp Basin contain mineralogically and texturally immature shales, submature and mature sandstones (generally classified as feldspathic litharenite and quartz arenites) deposited on a stable tectonic platform during the Mesozoic. Deposition took place under an overall transgressive regime. The delicate balance between sediment input and basin subsicence is exemplified by the development of a very thick lagoonal/tidal flat sequence, the occurence ofglauconite, the degree of maturity of the sandstones, and the lateral extension of the facies. Three different facies associations are distinguished: (1) Coastal/delta plain/tidal flat/shoreface (kobbe and Fruholmen Formations); (2) Lagoonal/shoreface/inner-middle shelf (Stø and Snadd Formations); (3) Shoreface/delta front/inner- outer shelf (Hekkingen and Kolmule Formations). The main reservoir sand bodies are found within the Kobbe, Fruholmem and Stø Formations. Both regional metamorphic (e.g. Caledonian and Precambrian) and sedimentary rocks (pper Palaeozoic), and minor volcanics are suggested as the major provenance for the sandstones.

54 Institutt for geologi og bergteknikk Hovedoppgaver 2002

Carbonate cements, mainly calcite and siderite (dominant), and kaolinite cement is the major destroyer of primary porosity in prolific sandstone reservoirs. Diagenesis is partly controlled by the depositional environment, which in turn is a major factor of porosity distribution.

Bakken, Torstein (S.O. Johnsen)

Automatic classification of sedimentary facies from wireline log data using the Bayesian Method, Tilje Formation, Smørbukk Field, offshore Mid-Norway. Automatisk klassifisering av sedimentære facies fra logg-data ved bruk av Bayesisk metode, Tiljeformasjonen, Smørbukkfeltet, utenfor Midt Norge. The objective of this task was to develop a tool in Microsoft Excel able to perform an automatic classification of sedimentary facies. The actual classification is based on datasets (trainingsets) including facies data and wireline log data, and the analysis of these sets. These analysis results in several characterizing log intervals for each facies, which then is integrated in macros made in Excel. Then the macros perform the classification on chosen datasets in Excel. In this way facies interpretation can be projected from cored wells onto non-cored wells. The method was used on datasets from 17 different wells in the Tilje Formation, and the results were compared to the original interpretation of each well. In the two wells used in the trainingset, the results were good, as expected. In addition there were five wells where the results were satisfactory, meaning that the fraction of readings correctly interpreted was quite high - around 70%. In most of the other wells the fraction of correctly interpreted readings were between 50 and 60 %, while only three wells had fractions below 50%. The main conclusion in the task was that the Bayesian Method is applicable for facies classification if the trainingsets are carefully analyzed.

Bolin, Mona (K.L. Sandvik)

Gjenvinning av ferrokrom fra slagg ved bruk av jigg. Recovery of Ferrochrome from Slqg by Jigging. Elkem Rana used magnetic separators to recover FeCr from slag. This process was not efficient as the magnetic properties of the FeCr varied as a result of some unknown conditions in the furnace. Gravity separation was shown to be effective in small scale testwork with a jig in a thesis by Hjørnevik in 1998. The smelter purchased a jig for full scale testing at the plant site. Bolin was conducting those tests. A separation with a high grade (direct saleable) concentrate was obtained with high grade feed. With lower grade feed the possibilities for a high grade was poorer. Working conditions during the testwork were poor as the jig was placed outside under winter conditions, limiting testing to mild days

Dahl, Jørn Morten (K.L. Sandvik)

Kostnadsanalyse i forbindelse med re-injeksjon og landbehandling av oljeholdig boreavfall. Cost Analysis Regarding Reinjection and Land Based Treatment of Oil Containing Drill Waste. This thesis analyses Statoil„s internal costs regarding the relative merits of reinjection of oil containing drill waste. It is confidential and kept in trust for 5 years.

Enoksen, Adler (E. Broch)

A study of long and deep traffic tunnels. En studie av lange og dype trafikktunneler. The 24,6 km Lærdal highway tunnel opened in November 2002 after a construction period of five and a half year. The tunnel was excavated through precambrian gneisses and few problems related to the geology, other than rock burst due to high horizontal stresses caused by the high overburden were experienced. The rock mass was supported in general with rock bolts and shotcrete. The cost of the project was 1,05 billions NOK. At present, the construction work on the Lötschberg Base Tunnel is underway in Switzerland. This partly two tube, 34,6 km long railway tunnel is excavated through the Alps and will experience an overburden of up to 2.000 m. The geology along the tunnel-line has been well investigated, for instance by driving an 9,6 km long exploratory TBM-tunnel in the northern part. The expected geological problems are linked to the high overburden generating high horizontal stresses, local intrusions of poor rock, inhomogeneous rock masses in the northern section and local water leakages with great force and magnitude. The rock support will in general consist of rock anchors/bolts, mesh and shotcrete, and when

55 Institutt for geologi og bergteknikk Hovedoppgaver 2002 necessary grouting and other water stopping actions will be performed. To achieve the needed aerodynamics a lining outside the rock support will be installed. The cost of the project is calculated to 3,22 billions CHF. It is clear that the two projects will experience much the same problems connected to high overburden. The planned rock support does not differ much between the two projects, but there are additional expenses in Lötschberg due to the investigations, planning, installations needed for the railway and the problems with water. Furthermore, the expenses in Lötschberg will increase compared to Lærdal due to the fact that Lötschberg is a more complex project, and because of a longer construction period, more manpower and administration.

Grenard, Samuel (S.O.Johnsen)

Å skape et 3D-bilde av Svea Nord-gruven (Spitsbergen). Building a /3D-picture of Svea Nord-mine (Spitsbergen). Coal is important in the Spitsbergen archipelago as it is the main source of income. It is therefore interesting for SNSK to know as much as possible about their new coalmine, Svea Nord. In this project an attempt has been made to make a 3D-picture of the deposit and to build a model for the deposition. Coal is mainly found in the Tertiary Central Basin in the central and southern part of the main island. It is assumed to be a transpressional foreland basin of paleocene age. The most important coalbearing unit is the Todalen Member of the Firkanten Formation. It consists of several deltaic deposits stacked on top of each other. It contains five main coalseams (Svea, Todalen, Longyear, Svarteper, and Askeladden). More than 50 cores drilled during the exploration phase has been used in this project. By correlation, 8 units have been identified of wich 7 are transgressive deltaic units. The apparent lack of deposits between the beach deposits of one unit and the swamp deposits of the one above indicates quick regressions between the units. The lowermost unit looks like tidal channel deposits, possible on a delta plain. No marine clays positively identifying the regressions could be observed as such clays would be hard to distinguish from clays deposited in swamps. Microscopical analysis of the clays below the coalseams would help solving this problem.

Horn, Anita Magdalena (A. Krill)

Geologi på Lille Raipas i Alta-Kvænangen vinduet, Finnmark, Nord-Norge. The Geological History of the Lille Raipas in the Alta-Kvænangen Window, Finnmark, Northern Norway. During summer 2001 I spent four weeks in the area of Lille Raipas, Alta, Finnmark, Norway. The work contained mapping and stratigraphic investigations, decription of stromatolites and karst phenomena in the area. Lille Raipas is part of the Alta-Kvænangen-window, an occurrence of Precambrian rocks in an area, which is mainly overthrusted by Caledonian nappes. The sequence of pre-Caledonian rocks consists of 3 main-units: the Raipas Group, representing Karelian time, the Bossekop formation from Late Precambrian and the Borras formation from Vendian. Stratigraphic works of all the three units, as also study of mineralogy, description of paleo-karst occurrences and stromatolite appearances could bring new perceptions about the geology of the Lille Raipas fjell. This work includes a map of the area in scale 1:5.000. There exist several paleo-karst occurrences, which could help to reinterpret the geological history of the area. I could show data that substantiate formation of karst after sedimentation of the Raipas-Group, during formation of the sandstone from the Bossekop-formation in Late Precambrian. Further it contains description and interpretation of the shape, lithology and preservation of stromatolites in the dolomite of the Lower Raipas, in regard to conditions during formation and linked with the history of the area. Because of weathering and recrystallization of the dolomitic rocks there are not enough characteristics and data to answer all questions about genesis and facies satisfactorily. Considering all available data, the stromatolites are interpreted as organo-sedimentary structures from an intertidal to supratidal environment. Their shapes represent a higher energetic water regime. The stromatolites underwent metamorphic and metasomatic processes that lead to recrystallization and destroyed the primary internal microstructure of the stromatolites. The very special copper ore paragenesis gives interesting information about geologic settings and geotectonic regime in the area in Precambrian time.

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Husby, Erik E. (K.L. Sandvik)

Prosesser for resirkulering, gjenvinning og gjenbruk av oljebasert borevæske. Processes for Recycling, Reclaiming and Reuse of Oil-Based Drilling Fluid. Oilbased drilling muds are used more and more. The effects upon marine life are questioned more and more. As a result no discharge into the sea is allowed. When the mud is returned to the bases recycling of the valuable component oil is possible. The thesis investigates different equipment for recovery of oil from returned mud and the quality of the recovered oil. In most cases the oil is comparable to new oil provided adequate removal of water. Upgrading of part of the mud itself is also an option. The most degrading part of the oil based mud is an increased water content. Removal of water was possible but the recovered mud was still not filling the specifications required. A solution is thought possible but more practical testwork is necessary.

Jjunju, Emmanuel (E. Broch)

Karuna Falls Hydropower, Project, Uganda. The Karuma hydropower project is located on the southern bank of the Nile River, 80 km downstream of Lake Kyoga in north central Uganda. It utilises the available falls (25 m) in the river by diverting water into an underground power station using a small weir instead of a large dam. The objectives of this study were to review the proposed design with respect to challenges and limitations of the project area basing on standard Norwegian Tunnelling Practice. Then, analyse the stability of the proposed surge chamber and Tailrace alternatives by numerical modelling. The main limitation during modelling was insufficient input parameters, as investigations are not yet completed. A number of assumptions based on past cases and theory, were made. Recommendations regarding the future design and Investigations have been made. In addition, the option with huge tailrace tunnels has been recommended (with some reservations), in stead of the one with surge and tailrace tunnels apart. The main reservation arises due to the hitherto un-investigated insitu-stress condition, rock-mass jointing and soil density among others, which are important as inputs to the model. The output of this study regarding rock support are sufficient for comparison of options but not for the final design until the inputs are verified with more investigations.

Karmacharya, Shailesh K. (S.O. Johnsen)

Geology of Nepal & Facies Distribution in Kathmandu Valley. Geologien i Nepal og faciesfordeling i Kathmandudalen. Muktinath gas seep and Dailekhs oil and gas seeps has been attracting petroleum geoscientists to explore Nepal Himalaya with a hope of hydrocarbon occurence in the country. Rock units of Vindhyan Super Group, Dailekha Group, Lakharpata Group, Gondwana Group and Surkhet Group have been considered as hydrocarbon bearing units. Geological, geophysical and geochemical analysis have been conducted in different stages but there are still many more detail investigations to do in order to get a correct signature. On the other hand, gas deposits of the “dissolved-in-water” type in the Qaternary deposits within the Kathmandu Valley has been considered as a positive natural resource which can be exploited in order to fulfill the energy demand of Kathmandu city dwellers. Altogether 25 borehole logs from Kathmandu Valley has been studied in this part of the work. Correlation of these logs helped to delineate fluvial and lacustrine depositional environment within the valley and that eventually became a good tool to prepare the facies distribution map. Therer are four boreholes that have encountered the bedrock. The elevation of the bedrock in these holes reveals that the basement topography is undulating and helpfull for the poundage of water. Presence of clay and sand in alternate fashion is helpful to store large amount of groundwater and organic matter in the clay is good enough to produce gas of the “dissolved-in-water” type. Exploitation of various natural resources, like marble, limestone, clay and sand, from the Kathmandu Valley will be more effective and helpful to the city dwellers if environmental aspects are considered at the time of exploitation.

Kassana, Leonard B. (B. Nilsen)

Analysis of water leakages at the Lower Kihansi Hydropower Project, Tanzania. In Tanzania, the Lower Kihansi Hydropower project, utilising a head of about 850 m in an unlined tunnel system, was put in operation in year 2000. The entire system of tunnels and power plant is located underground in Precambrian rock mass. During water filling, leakage from the headrace tunnel was experienced, and also some minor leakage into the powerhouse.

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The main purpose of this thesis has been to analyse the water leakages during water filling in relation to the engineering geological and rock mechanical characteristics of the project site. The work is focused primarily on the rock engineering aspects of the project, with main emphasis on:

 Correlations between water leakage and the engineering geological conditions.  Possible future development of the water leakage. The study has found that the major two aspects correlating and linking water leakages and engineering geological characteristics are weathering and jointing/faulting in the project area.

Livik, Steinar (B. Nilsen)

Ingeniørgeologisk analyse av Korgfjelltunnelen. Rock Engineering Analysis of the Korgfjell Tunnel. For the Korgfjell tunnel, a 8.5 km long road tunnel under excavation in Nordland, analysis of the rock engineering conditions has been carried out. Various geological maps and reports have been available as background material, and as part of the present work field mapping, sampling and laboratory analyses of rock samples have been carried out. The predominant rock types in the project area are micaschist/-gneiss and marble. Based on evaluation of the engineering geological characteristics such as rock types, weakness zones/faults, groundwater conditions and rock stresses, the tunnel project is considered to be of medium geotechnical complexity.

Lundhaug, Nina J (S.O.Johnsen

Migrasjon av hydrokarboner på Ekofisk. Migration of hydrocarbons in the Ekofisk area. To investigate what effect different heatflow histories have on the maturation of organic matter and migration of hydrocarbons, three cases (case 2,3, and 4) from the Ekofisk field was modelled in Glview, BAS and Mig3D. This is important in order to find out if there are intervalls that should be modelled with greater accuracy than others. Comparisons of Case 2,3, and 4 shows that when modeling a succession, one has to lok at the geological history and the development of the pressure and temperature to find out if some parts needs more accurate treatment. It is important to know when the maturation of the organic matter starts. The use of modelling tools will therfoer require a good geological understanding of the area to be evaluated, and knowledge about the factors controlling the maturation of the organic matter, and the mechanisms controlling the migration.

Mellgren, Anna (M. Thornhill)

Utluting av nikkel fra Lundetjern landdeponi - En kartlegging av årsaker og tiltak. Dissolved Nickel in the Lundetjern Land Deposit - Identification of Main Causes and Methods for Treatment.

Nilssen, Per (A. Myrvang)

Vurdering av boltesikring i Svea Nord. Evaluation of Rock Bolt Support in the Svea Nord Mine.

Pettersen, Mari S. (S.O. Johnsen)

Application of log based lithofacies classification tools on Oseberg East field data. Anvendelse av logg baserte litofaciesklassifikasjonverktøy på feltdata fra Oseberg Øst. The objective of the work was to dig and report on the most well known theories and methods for lithofacies classification from well logs. Then to test, apply and conclude on one of the newest electrofacies analysis methods using real data from the Oseberg East Field. A commercial data program called Geo Frame was used in the work and several modules was applied. The most important ones was the Well Composite Plus module, used to print and graphically present the well logs, and the Rock Cell module that was used to classify drilled sedimentary sequences into lithofacies.

Rise, Torun (T. Malvik)

En utredning av mulighetene for blokksteinsproduksjon av Ballangen dolomitt. Investigation on the possibilities of the production of natural stone from the Ballangen dolomite.

58 Institutt for geologi og bergteknikk Hovedoppgaver 2002

During examinations of the Ballangen dolomite‟s suitability for production of natural stone, several test methods have been accomplished. Field investigation samples from the Ballangen dolomite were studied macroscopicly, and boreholes from earlier core drillings at Hekkelstrand (2000, 2001) and Nilsheimen (1995) were logged with a view to colour and fractures. The results from the field investigations were not put much stress on because of whethering in the dolomite samples and difficulties with defining the cause of the fractures. The Ballangen dolomite was also studied during several laboratorial testing methods, and then compared to other marbles in the marked. The methods executed in the diploma thesis were petrographic description, XRD-analysis, determination of real density, porosity, water absorption, compressive strength, flexural strength, bowing, speed of sound, whiteness and chemical composition. The results of these investigations showed a dolomite with a technical quality similar to other marbles in the marked. Based on this, it was concluded that the Ballangen dolomite can be used in production of natural stone. Based on geological maps from the Håfjellet/Skårnesdalen-area drawn by geologist Ulrik Søvegjarto, a geological model was made of the area of interest. This geological model formed the basis of planning and accomplishing a core drilling program. The results of the core drilling showed a less white and more fractured dolomite than assumed in the geological model. In regard to this information, it was concluded that the whethering in the Håfjellet/Skårnesdalen-area has been more intense than assumed in the model. Colour and fractures are two of the most important quality parameters in association with productions of natural stone. Based on the results from the core drilling, the Ballangen dolomite is yet not actual for production of natural stone, even though the technical quality indicated that a production was possible. It is still recommended that the area of interest is studied further, with a view to chart a possible resource to the existing production at Hekkelstrand.

Rusfeldt, Helge (K.L. Sandvik)

Avslammingsprosess sammenlignet med vaskeprosess. Process Desliming Compared to Washing. Confidential Hustadmarmor is the world‟s largest single producer of ground calcium carbonate (GCC) for the paper industry. Prior to the processing fines is washed away to avoid problems in the removal of impurities. This leads to large calcite losses and large tailing flows to the fjord. The thesis looks at solutions to avoid this loss. The thesis is confidential and kept in trust for five years.

Singh, Shova (S. Lippard)

Study of Early Tertiary Fault Reactivation, Mud Diapirism and Gas Migration in 3D Seismic Data of the Gullfaks Field. Two early Tertiary reactivated faults are identified from the 3D seismic sections of the Gullfaks area. Attribute and StratAmp map analysis are used to map the trend and extent of these faults. Both faults dip towards east and found in the northeast part of the area. The first normal fault trends NW-SE and the second fault first trends to N-S and then to NW-SE, parallel to the first one. The second fault has both normal and reverse displacements and an inversion structure is associated with the reverse part of the fault. These NW-SE trending faults may be the extension of the Troll Lineament, which has been traced from the Bergen area to the northeastern part of the Gullfaks Block. The early Tertiary reactivation may be related to the tectonic movements caused by the change in the stress pattern from NE- SW to NW-SE Compression. Seismic mounds observed at the Base Utsira in the Gullfaks area are considered to be formed by the mud diapirism. Mud diapirism occurred due to the hydroplastic deformation of the marine clay of Hordaland Group in the presence of the vertically migrated gas. Seismic evidence of vertical migration of gas are seismic chimneys, high amplitude anomalies with bright spots and chaotic zones with V-shaped brights. These anomalies are found in the Cenozoic successions in a vertically stacked manner suggesting gas migration from a deeper source to the seabed. Disturbances seen in the water column may also suggest the presence of gas. The same NW-SE trend of the amplitude anomalies with bright spots and the early Tertiary faults may suggest that gas migration is probably associated with early Tertiary fault reactivation.

Sveen, Sølvi (T. Myran)

Svevestøv i Helltunnelen og Elgesetergate i Trondheim. Road Dust in Hell Tunnel and Elgesetergate in Trondheim.

59 Institutt for geologi og bergteknikk Hovedoppgaver 2002

Todnem, Lillian (A. Myrvang)

Transportstoll fra Svea Nord, Svalbard. Vurdering av mekaniske driftsmetoder. Haulage adit from the Svea Nord coal mine, Svalbard. Evaluation of mechanical excavation methods.

Truong, Thi Kim Thi (K.L. Sandvik)

Utprøving av optisk sortering på prøver av aluminium skrap og olivin. Testing of Optical Sorting on Aluminium Scrap and Olivine Samples. An optical sorter has been developed at the Department to sort recycled metals as well as natural minerals. A commercial image analysis system named IMAQ was used to investigate the possibilities to separate scrap Al profiles from Al cast material and other metals as well as olivine and nonolivine minerals in a dunnite. The work was based upon images of particles on a belt and computer simulation of the sorting process. For the metal case, separation had to be based upon shape, as the colour could vary as a result of paint or dirt. Pretreatment of the scrap is an important factor as it affects the shape factor. Separation of olivine could on the other hand be based upon colour differences. The light source was in this case of critical importance. The dunnite was not well suited for any separation as the degree of liberation was low.

Wien, Stein Tore (S. Lippard)

Structural Restoratin of the Northern North Sea Post-rift Bathymetry. Palaeobathymetric reconstruction of the Cretaceous and Cenozoic post-rift interval of the northern North Sea has been performed using the restoration tool SEMI Palaeowater. By utilizing geometrical constraints, 3D bathymetric maps of 14 time steps have been created. Based on the restorations, an animation illustrating the basin evolution was made. The early Cretaceous bathymetry was highly influenced by the Jurassic rift topography. During the late Campanian the Jurassic structural elements were overprinted, and at the latest Maastrichtian, no trace of the rift relief was evident. Water depths in the Cretaceous restorations were integrated with micropalaeontological interpretations, and the two independent methods show a good correlation. at the transition into the Cenozoic, water depths increased. Large water depths prevailed until the Oligocene, when significant shallowing took place. A new deepening occurred during the late Miocene - early Pliocene, while renewed shallowing was observed in the late Pliocene - recent. The Cenozoic bathymetric development was highly influenced by episodic uplift of the flanks.

Aasum, Linda Beate (K. Sundblad)

Geologisk og petrologisk undersøkelse av baryttgangene ved Zeipeldalen og Ridderborgen, Svalbard. Geological and petrological investigation of the barite veins at Zeipeldalen and Ridderborgen, Svalbard.

Aavik, Gunnar (K.L. Sandvik)

Gjenvinning av glass ved Miljøtek Hasopor AS. Optimalisering av knuse- og maleprosessen med hensyn på totaløkonomi. Reuse of glass waste at Miljøtek Hasopor AS. Optimalization of the comminution process. Miljøtek Hasopor is a company set up to convert glass waste into foam glass for insulation and lightweight construction bases. The process is especially intended to bind poisonous heavy metals into inert glass matrixes. Wear of the comminution equipment caused high operational costs and the purpose of the work was to find ways to reduce those. The conclusion of the work was that considerable savings could be obtained by moving some of the comminution work from the hammer mill to the ball mill.

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2001

Andersen, Katrine (S.O.Johnsen)

Sedimentologisk studie av Midtre Jura avsetninger i Søgne bassenget, Sentral Graben. A sedimentological study of Middle Jurassoc deposits in the Søgne Basin, Central Graben. In the Søgne Basin of the Danish Central Graben, North Sea, the Middle Jurassic comprises sandy deposits of the Bryne Formation. The upper part of this formation has been the subject of a sedimentological study, in order to learn more about the depositional environment and distribution of these sediments. Cores from two wells in the area have been examined. The Lulita-1x core comprises sandy, coarsening upwards units with strong wave influence. These are interpreted to be prograding shoreface, beach and barrier island deposits. The West Lulu-3 core also contains sandy units, but of different facies than the Lulita-1x. The sediments are tidally influenced, and probably deposited in a more protected and landward area. They are interpreted to be channel and tidal flat deposits, possibly in an estuarine or protected bay environment. A sequence stratigraphic subdivision is carried out based on the results from core interpretation and well log patterns of Lulita-1x and West Lulu-3, and well logs from five additional wells in the area. The GR-logs and sonic logs show similarities between the wells, and permits correlation of key surfaces and units. The upper Bryne Formation is subdivided into three sequences, that represents three cycles of rise in relative sea-level. In the western and most landward wells, the LST and TST deposits dominate. The HST deposits are thick in the wells situated closer to the central parts of the basin and wedge out towards land.

Cieza, Jerome (K.Nielsen)

Verktøy for bærekraftig utvikling i små og mellomstore bedrifter og dets fordeler. Conceptual framework tool for sustainable development in small and medium sized enterprises, and its benefits.

Eldholm, Erlend (S.Lippard)

Forholdet mellom 1D brønndata og 3D geologiske modeller. Relation between 1D well samples and 3D geological models. A work flow for comparing 1D well data and 3D geological models has been developed for fault data and tested on two fields. First the 1D fault density from the wells is established and a 3D model built. Then synthetic wells are sampled in the same directions as the real wells. The synthetic fault density is then compared with the real fault density. If the fault density of the model is too low, new faults have to be simulated. The parameters for these faults are found from the faults already in the model or can be chosen from other fault sets described in the literature and sound geological knowledge. When these parameters are established, the number of faults that need to be simulated can be estimated. The process is repeated until the model and the well data match.

Helsem, Andreas(R.Sinding-Larsen/STATOIL)

STATOILs tilgang på leteareal på 1990-tallet. Statoils access to exploration acreage in the 1990’s.

Hunsbedt, Tor Ingolf (A. Myrvang)

Rasutvikling i samband med longwallbrytning i Svea Nord. Caving development in connection with longwall mining in the Svea North Mine. In this diploma thesis the caving development in the longwall operation in the Svea Nord mine of Store Norske Spitsbergen Kullkompani has been simulated with the numerical modeling code UDEC. Two situations have been modeled, one with large overburden and one with smaller overburden. The scope of this analysis is to evaluate the far the cracking from the caving will propagate above the mined area, from this analyze the risk of water intrusion from the glacier above the mine. The general stress-situation around the longwall is also of interest, with particular emphasis on how the stresses will build up front and in the caved area as the longwall is advancing. The results show that the caving propagates about 20 m above the mining area for both models. Above this, the rock will only converge because of high horizontal stresses. Some crackings will develop, but further above the coal seam the cracking will be less. There is little reason to assume that water will intrude from the glacier above as a result of caving of

61 Institutt for geologi og bergteknikk Hovedoppgaver 2001 the roof rocks. The stress transfer from the overburden rocks through the caved material will be fully restored about 150 m behind the face. The maximum load on solid coal ahead of the face is reached at this stage. This load will remain the same when longwall advances, provided the overburden is the same.

Kopperud, Espen (S.O. Johnsen/Phillips Petr.)

Facies analysis of the Devonian and Permian reservoir units in the Embla field. This thesis study demonstrates the practical applications of fluvial bounding surface theory (after A.D. Miall, 1996). By giving the bounding surfaces, observed in core samples of the Devonian and Permian braided stream deposits in the Embla Field, a hierarchical number, it is possible to get a systematic classification of the fluvial architectural elements. Estimation of a single-story channel, by using correlation schemes. These estimations are predictive for the lateral continuity of the reservoir layers.

Kvarsvik; Susanne (S.O.Johnsen/M. Landrø)

Analyse av Øvre Jura prospekter ved Gullfaks. Analysis of Upper Jurassic prospects - Gullfaks. In 1999, Saga Petroleum made hydrocarbon discoveries in Upper Jurassic sandstones to the North of the Gullfaks Field in wells 34/7-21, 34/7-21A, and 34/7-25S. Recently Statoil observed some strong seismic amplitudes to the west of Gullfaks West. Purpose of the present thesis was to do a thorough seismic interpretation to see if the same Upper Jurassic sands were present in the area to the west of the Gullfaks Field. Seven prospects have been analysed and mapped and an AVO analysis and a fluid substitution have been performed on each prospect. This resulted in four prospects that may contain hydrocarbons.

Nakstad, Rune (K.L. Sandvik)

Bruk av keramiske membranfiltre for behandling av industrielt prosessvann. Application of Ceramic Membranes to Industrial Water and Wastewater Treatment.

Nordstrand, Jo Svenningsson

Energibrønner i fjell - Vurdering av forskjellige

Nghia, Trinh Quoc (Einar Broch)

A Study of the Tunnel & Underground Powerhouse for Rao Quan Multi-purpose Project Quang Tri, Vietnam. The Rao Quan project is located in the centre of Vietnam. The project is combined between hydropower, irregation and flood control. Key parameters are: Maximum head 450,8 m, discharge 19,6 m3/s, installation capacity 2 x 35 MW. Based on the Norwegian approach in designing underground structures the tunnels, the pressure shaft and the powerhouse of Rao Quan hydropower project are redesigned as unlined tunnels. The Q method was used to classify the rock mass and the tunnels support was designed based on this method. Numerical models were established to analyse the stress situation around tunnels, pressure shaft and powerhouse. Due to low stress, the headrace tunnel should be lowered and the pressure shaft should be relocated or inclined. The results also indicate that the powerhouse is located in relative good area. The construction of tailrace tunnel may face stability problems due to high concentration of stress. The numerical models also looked into the influences of weakness zones to stress distribution.

Nordstrand, Jo Svenningsson (B. Brattli / NGU)

Energibrønner i fjell - Vurdering av forskjellige metoder for effektuttak ved et demonstrasjonsanlegg. Energy wells in bedrock - Evaluation of different methods for power extraction in a demonstration plant. This Diploma thesis is part of a project to examine the possibility of increasing the amount of energy extracted from energy wells by use of hydraulic fracturing. In connection with this a demonstration plant was developed at Bryn School in Bærum. The thesis topic is limited to assessing the different factors that affect thermal constructions and looking at the amount of power extracted from the wells at Bryn School. The demonstration plant is unusual because the wells are fractured so that there is communication between them. The energy carrier (water) is injected into the central well and will flow via cracks where there is adjacent heat exchange with the bedrock, it is then pumped up from four satellite wells.

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The fieldwork started with the drilling of the wells and collection of cuttings, and since then has concentrated on carrying out capacity testing, groundwater analyses, borehold logging and hydraulic fracturing of the wells.

Nygaard, Gertie (K.L.Sandvik / N.Shell)

Usikkerhetsstyring av offshore prosjekter (case Norske Shell). Risk and Opportunity Management in Offshore Projects (case Norske Shell).

Næss, Øystein H. (R. Sinding-Larsen)

Utforming og vurdering av et e-læringsopplegg som støtte for effektiv bruk av et prospektevalueringssystem. Elaboration and Assessment of an E-learning Environment in Support of Efficient Use of a Prospect Evaluation System. Står også registrert på Silje Tokvam.

Pimenta de Miranda, Wilfred (K. Nielsen)

Miljø- og energiproblematikk i utviklingsland. En oversikt over utfordringer og muligheter for bærekraftig utvikling. Environmental and Energy Issues in Developing Countries. An Overview, from the Third World Perspective, of the Challenges and the Opportunities for a Sustainable Development.

Rustad, Odd-André (E.Broch)

Injeksjon av finkornet sement - forsøksmodeller. Grouting with micro-cements, - test models. Praktisk del: Delta i utvikling av en modell med vekt på instrumentering. The thesis describes a new physical model for testing of micro-cements as grout material. Emphasis is on the instrumentation of the model.

Tangen, Kjell A. (K.L.Sandvik/ Sonsub AS)

Proposal for an environmental and economical wastemanagementplan at Sonsub AS Forslag til miljøvennlig og økonomisk bedriftsavfallsplan for Sonsub AS.

Tilahun, Daniel (B. Nilsen)

Engineering Geological Analysis of Tunnels, Shafts and Caverns at Gilgel Gibe Hydropower Project. The 180 MW Gilbel Gibe Hydroelectric Project in Ethiopia is situated some 260 km South-West of Addis Ababa. The project includes about 9 kilometres of tunnels, several shafts and caverns, including a 25 meter wide powerhouse cavern. In this thesis, a detailed engineering geological analysis of tunnels, shafts and caverns has been carried out, with the following engineering geological aspects in main focus:

 The feasibility of unlined headrace tunnel as alternative to the selected lined alternative.  Design and planned rock support of the powerhouse cavern.  Selected rock engineering design of caverns and tunnels as compared to standard designs. Numerical modelling (Phase2) is included in the analysis, and comparisons have been made between deformations calculated by Phase2 and deformations measured in the powerehouse cavern.

Tokvam, Silje (R. Sinding-Larsen):

Utforming og vurdering av et e-læringsopplegg som støtte for effektiv bruk av et prospektevalueringssystem. Elaboration and Assessment of an E-learning environment in Support of efficient Use of a Prospect Evaluation system. Står også registrert på Øystein H. Næss.

Werningsen, Camilla (S.O. Johnsen / BP)

En stratigrafisk utvikling fra Eocen til Resent over Dønnaterrassen og Nordlandsryggen i blokk 6507, midt Norsk sokkel. A-stratigraphic development from Eocene to Recent over the Dønna Terrace and Nordland ridge in block 6507, Mid- Norwegian continetal shelf.

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Eleven depositional units are mapped in this study from Eocene to Recent. The division of the units is based on biostratigraphy, seismic unconformities and seismic reflection terminations. At the Paleocene-Eocene boundary active seafloor spreading started. This led to basin subsidence and a transgression in the beginning of Eocene. The initiation of seafloor spreading resulted in a compressional stress regime and resulted in uplift of the mainlandand the transgressive phase was interrupted by regression in Middle Eocene. The separation of Greenland from Svalbard in Eocene-Oligocene probably resulted in a renewed uplift in this period. In the beginning of Miocene there was a relative sea-level rise caused by subsidence in the area. In the Middle Eoceneasymmetric uplift and tilting of the mainland resulted in regression. The uplift and the initiation of glaciations resulted in large prograding wdges over the shelf area and the Pliocene-Pleistocene boundary lies probably in one of these prograding wedges. A large unconformity truncating the underlying prograding wedge is related to a sea-level drop and an advance of the glacial front. It can also mark the transition from Pliocene to Pleistocene. The uppermost units probably represent the Weichselian glaciations on the shelf and the last deglaciation.

Ziada, Ahmed M. (S.O. Johnsen, MSc)

Sequence stratigraphic interpretation of the Neogene succession in the Tokar Delta, Sudanese Red Sea. The Tokar Delta form a part of the Suez-Red Sea rift system. Seismic and well data has been provided to evaluate the basin. These data were integrated with Exxon depositional model and Galloways genetic model to identify the sequence boundaries within the study area. Analyzing, interpreting and mapping of the reflection packages of the seismic sections a coherent framework of seismic sequences were identified within the Neogene succession of the Tokar Delta. The structural development is dominated by pre-existing structural trends of Precambrian age and their response to major events of global tectonics. Basin subsidence, climate, rate of eustatic sea level change, the sedimentary supply from the red sea Hills and the listric faults structural style are the main factors controlling the sequence pattern and the lithofacies distribution of the Tokar Delta. The seismic reflections in the study area show reflection configurations and continuity of a shelf system. The associated seismic facies indicate fluvial, fan-delta, shel/platform, shelf edge facies and slope patterns. The deep drilling coupled with geophysical data suggested the presence of sedimentary sequences of some 4000m. The subsurface sediments are structurally controlled which resulted in favorable juxtaposition of source, reservoir and seal. Oil and gas shows have been encountered in the basin. Seismic sequence S2 of the Maghersum Group is the highly prospective sequence in the Gulf of Zues. The primary objectives in the Tokar Delta were in the Miocene (sequence 4) of the Zeit Formation.

Øyan, Knut Espen

? uferdig med prosjekt ennå i des. 2000 .flyttes til liste for år 2001. Tlf. med (B.Nilsen)

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2000

Anthi, Aina Katharina (B. Nilsen / Statens Vegvesen Oslo)

Stabilitetsanalyse av vegskjæringer i Oslo-området. Stability analysis of road cuts in the Oslo area. Along main highways in the Oslo area, such as E18 Mossevegen and E6, there are several large road cuts. In this thesis a selection of the most relevant cuts have been analysed regarding stability condition, existing rock support, history of earlier sliding/rock fall activity and risk of future instability. The requirement for new/additional rock support has been evaluated, and alternative technical solutions and cost of new/additional support have been discussed. A considerable number of locations have been found where additional support is recommended, and list of priority for the recommended measures is proposed.

Aslaksen, Kari (S.W. Danielsen)

Kartlegging av ressurspotensialet i Lia pukkverk. Mapping of the resource potential at Lia Pukkverk.

Berg-Hansen, Espen (K.L. Sandvik)

Gjenvinning av kalkspat tapt ved vasking. Recovery of fine material that is lost in the washing circuit. Confidential The thesis describes testwork done to increase recovery of fines in a casciite cleaning plant.

Bhuban Prasad Dhakal (B. Nilsen / Norad)

Engineering geological analysis of Nyadi Hydropower project, Nepal. For the proposed 15 MW Nyadi Hydropower Project West of Kathmandu in Nepal, a feasibility study has been carried out by Butwal Power Company. The plans include about 5 kilometres of tunnels, pressure shaft with about 350 meters static head and underground powerhouse cavern. This thesis represents a detailed engineering geological analysis of the proposed project, including all aspects of design, stability and rock support. The work is focused on the engineering geological aspects of the planned project, such as: location of the pressure shaft and the feasibility of the unlined shaft alternative, location and design of the powerhouse cavern, stability of the headrace tunnel, and the rock support requirement of the powerhouse cavern and the various tunnels.

Edvardsen, Thomas Melsom (K. Sandvik)

Miljøstatus ved Mazowe Mine Environmental Status at Mazowe Mine. This work was carried out as an exchange project with the University of Zimbabwe. Zimbabwe is getting new environmental laws and there is a need to assess the current situation. The candidate has surveyed the water situation around the mine and has done a good job on identifying what is happening in the water circuit. He has also pinpointed problem areas and suggested solution to some of the problems discovered.

Eggen, Bjørn Erling (B. Nilsen / Statens Vegvesen)

Analyse av metoder for driving gjennom svakhetssoner i Frøyatunnelen. The Frøya subsea tunnel-Analysis of tunneling methods through weakness zones. Based on available background material, interview with site staff members, field investigations and laboratory testing, methods used for tunnelling through weakness zones at the Frøya subsea tunnel have been evaluated. Field investigations were focused mainly on the remaining 100 meters of the tunnel, but also covered other sections. Laboratory testing mainly covered properties of gouge material and the adhesion of shotcrete used for rock support. A combination of conventional rock bolting and shotcreting, spiling and shotcrete arches was often used as final support, and proved to be succesful.

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Einarsson, Eirikur (B.Nilsen / Vegegerðin / BAH)

Siglufjördur-Olafsfjördur vegtunneler, ingeniørgeologisk og anleggsteknisk analyse. Siglufjörður-Ólafsfjörður Road Tunnels, Rock engineering analysis At Siglufjörður-Ólafsfjörður in Iceland, two road tunnels of lengths approximately 4.0 km and 6.0 km are planned. This thesis evaluates engineering geological and construction engineering factors, such as rock mass conditions, earthquake activity, requirement of rock support and lining and cost/scheduling of the planned project. As basis for the evaluation, geological reports and relevant documents from pre-investigations have been available, and additional field work and sampling have been carried out by the candidate. Particular emphasis has been placed on groundwater conditions and methods for solving potential problems caused by water. Uncertainty analysis and a comparison between Icelandic and Norwegian cost levels are included in the cost analysis. The main challenges of the project are believed to be represented by geothermal areas/groundwater and strong seismic events.

Fliss, Andreas (E. Broch / Technische Universitet Freiberg)

Optimization of block size in breakwater quarries. Engineering geological studies have been performed at three breakwater quarries in Northern Norway with particular emphasis on the influence of discontinuities on block size. Rock sampling and laboratory testing has also been carried out. The general conclusion is that fragmentation in quarry blasting is not controlled by a single parameter, but by a combination of the degree of jointing, rock density, wave velocity of the rock degree of decoupling, explosive density, specific charging, delay times and the geometry and orientation of the drill pattern.

Foyn, Sven Erik (S. Lippard)

Strukturell rekonstruksjon av palaeobathymetri i Vøring-bassenget. Structural reconstruction of Palaeobathymetry in the Vøring Basin.

Glass, Christopher (A. Krill)

Strukturelle forhold mellom bergarter i Ytre-Fosen området og Devonsk ekstensjonstektonikk. Structural relations of rocks in the Outer Fosen area to Devonian extensional tectonics. Old Red Sandstone basins in the Outer Fosen area have formed as a result of crustal extension in the Devonian Along the Høybakken Detachment. This has led to upper-plate rocks of a higher level in the Caledonian tectonostratigraphy being juxtaposed with lower-plate rocks of a deeper level. The basins consists of continentally derived conglomerates and sandstones folded as gentle NE-plunging synclines. The main source regions were proximal areas underlain by granite and diorite plutons. Formations of pre-Old Red Sandstone on Ørlandet are the Lerberen Granite, the Brekstad Metasediments and gneisses. The granite is a Caledonian pluton dated to 442 +/-2 Ma (U-Pb, zircon), that falls in the same period as the formation of granitoid rocks on Hitra and Smøla. No sign of ductile deformation is apparent in the rock but it has been penetrated by brittle fractures. Their main orientation, striking NE-SW, corresponds with Devonian/post-Devonian brittle deformation in the Bjugn Basin. Subordinate NW-SE striking fractures might reflect the Devonian extensional event. In certain areas the granite has been grind down to cataclasite. A brief investigation of conglomerates in the Bjugn Basin confirmed the dominans of granitoid clasts. Clasts similar to the Brekstad Metasediment were also detected.

Hallingstad, Jon-Olav (S.O. Johnsen)

Kartlegging av topp Hordaland reflektor på Gullfaksfeltet. Mapping of top Hordaland reflector in the Gullfaks Field.

Haneferd, Helen (A. Krill)

Geologisk kartlegging i Courbonsområdet, Alpes de Haute-Provence, Frankrike. Geological mapping in the Curbons area, Alpes de Haute-Provence, France. This is a thesis of geological mapping in the southern subalpine chains in Haute-Provence in France. The subalpine zone is in the area represented by an allochthon called the Digne Nappe or the Digne overthrust (Debelmas, J. et al. 1983). The mapped area is situated north and westof the town Digne les Bains and consists of five different tectonic units. One allochthon unit, the autochthon at Courbons and four allochthon units, the Isnard-, the Givaudan-, the Roche

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Rouge- and the Gomar units. The allochthon units can be considered as internal units in the Digne Nappe, but are here treated as separated tectonic units. One of the aims of this thesis was to find out whether the four tectonic units actually were four tectonic units or if some of them were the same.

Hansen, Morten Krogh (S.O. Johnsen)

Utsiraformasjonen, den massive sandsteinen, provenance og utbredelse i Jotun- og Balder-området The Utsira massive sandstone, provenance and distribution in the greater Jotun and Balder area. An interpretation of the massive sandstone interval of the Utsira Formation, North Sea is presented. The Utsira massive sandstone is interpreted as overall stacked lowstand fan deposits, sourced from the Shetland Platform. These were deposited on the basin floor as a result of tectonic uplift of the basin flanks combined with a glacio- eustatic sea level fall. The fan constitutes a lowstand fan systems tract of a 2nd order sequence, which further is subdivided into four 3rd order sequences. Boundaries between the 3rd order sequenses are recorded as regional correlative condensed sections draping each sequence. The lowstand fan is up to 300 m thick west and northwest in the study area, but it thins rapidly towards the southeast. It comprises the middle and outer part of a classic fan-system, the former consisting of many deep-marine channels. The channels are feeding distinct depocentres within the study area, and due to loading of extensive amounts of sand, forced shale diapirism activity of underlying Oligocene and Lower Miocene clay is thought to control much of this deposition.

Hansen, Ståle (S.O. Johnsen)

Petrologisk evaluering av reservoarsammensetning, diagenese og relasjon til borehullslogger, Mesaverdegruppen, Rock Springs, Wyoming. gruppen, Rock Springs, Wyoming. Petrological evaluation of reservoir quality, diagenesis and relation to bore hole logs, Mesaverde Group, Rock Springs, Wyoming. The Mesaverde Group makes up most of the late cretaceous deposits in The Rock Springs area in SW Wyoming. The sediments mainly vary between channel deposits and coastal deposits. The where deposited during threee large depositional cycles, showing prograding, aggrading and retrograding trends. The rocks investigated show to a large degree very good reservoir properties, which is a function of provenance, facies and to some extent diagenetic processes. Relatively coarse grained high energy deposits shows the best reservoir properties. The rocks of the Mesaverde Group have probably not been buried deeper than1,5 – 2,5 km. This is reflected as a low content of quartz cement. Important diagenetic minerals are first of all carbonates, especially ankerite and dolomite. Reduction of primary porosity is caused by mechanical compaction and precepitation of authigenic cement. The two processes seems to be of the same importance. Th analytical methods used in this study have been optical microscopy, XRD, SEM and TS. The analytical results for the different methods seems to be small for the most common and important minerals found in the sandstones.

Hellerslien, Ragnar (E. Broch)

Injeksjonsarbeidene i Baneheitunnelen. Grouting of the Banehei Highway Tunnel. 0In the Baneheia area of Kristiansand a 3 km long highway tunnel passes through an area which is very vulnerable to a lowering of the groundwater level. The max leakage allowed into the tunnel was 2 liters per minute per 100 meter. In order to comply with this, the sealing method used was continuous pre-grouting. The grouting program consisted of 30 holes, or more, with a length of 21 - 24 m, grouted at 50 bar pressure. The overlap was 8 meters. Only cement based grout was used, consisting of microcement, with microsilica and superplasticising additives. Probe drillholes were performed and leakage measurements were carried out in these. Three times more grout than planned, has been used, but the use of shotcrete and rock bolts have been considerably lower than planned, which means that the grouting has had a stabilising effect on the rock masses. Comparisons of data from the mapping and grouting operations in the tunnels has been carried out in order to see possible relationships between geology and the consumption of grout. From the surveys of Q- and RQD-values it seems that there is a tendency towards a decline of grout consumption when values increase. There are, however, large variations. When grouting into joint set striking parallel to the tunnel axis, both more time and more grout were needed to obtain the same result as when grouting into joint set striking perpendicularly to the tunnel axis. The grout moved considerably far in

67 Institutt for geologi og bergteknikk Hovedoppgaver 2000 virginal rock masses, and this assumption is also confirmed by the fact that less grout consumption took place in tunnels which were located near pipes that had been grouted earlier. The gouting of the Banehei tunnel has been successful. The demands for sealing, time limits and economy have all been adhered to. The reason is mostly due to a contract formulation that gave priority to required time and costs connected with sealing operations.

Hessen, Kristian (K. Nielsen)

Planlegging av underjordsdrift i Raubergvika. Planning of underground mining in Raudbergvika.

Husby, Øyvind (S.O. Johnsen)

En demonstrasjon av detaljerte migrasjonskonsepter på en analog av dypmarint system – en applikasjon av invasjons perkulasjons teori. Demonstration of a detailed oil migration concepts on an anlogue of deep water systems – an application of invasion percolation methodology. Accurate modelling of petroleum migration pathways is critical to successful oil exploration, since it provides the basis for accurate prediction of reservoirs filling history, and helps in risking prospective accumulations evaluation parameters. Assesing secondary hydrocarbon migration effectiveness, particulary in areas with lithologically heterogenious carrier beds, is a critical trap evaluation task. This study develops a technique for modelling secondary hydrocarbon migration using outcrop derived, analouge data. Facies and lithology descriptions from an erosional/depositional channel of a Permian deep water clastic turbidite system were used as modelling input. Flow parameters (capillary threshold pressure, porosity, saturation) were assigned using data from Statoil‟s petrophysical database and published litterature, and hydrocarbon fill simulations were carried out with the PermediaTM Invation-Percolation code. After each simulation, the hydrocarbondistribution and saturation were analysed to determine the dependence of facies and lithology on hydrocarbon fill patterns. Results from the analouge show that the hydrocarbon distribution and saturation, are controlled by flow propery contrasts and the distribution of heterogeneity within the channel. Results show that fill patterns are strongly controlled by the geometry of high capillary threshold pressure facies (i.e. shale), and are strongly dependent on the degree of contrast in petrophysical properties within the carrier rocks.

Janbu, Nils Erik (S.O.Johnsen)

Karakterisering av autigen kloritt og andre sementtyper med vekt på kvartsovervekst,Tiljeformasjonen på Smørbukkfeltet Characterisation of authigenic chlorite and other cements, with emphasis on quartz overgrowths, from the Tilje Formation in the Smørbukk Field. Chlorite and other authigenic phases in 31 samples from sandstones in 4 wells in the Tilje Formation from the Smørbukk Field have been characerised. New observations state that chlorite rims are intergrown with, and growing on, poorly crystallised quartz overgrowths. These observations lead to changes in the view of timing for chlorite rim formation. The main phase of chlorite rim formation may have been during or after the initiation of quartz cementation. Chlorite rims are not growing on perfect faces of any authigenic phases. It is possible that the chlorite rims need a suitable substratew in order to grow. Dissolution and short range spatial redistribution of a Fe-rich precoursor seems to be the most probable mechanism for the formation and growth of the chlorite rims. The presence of chlorite-rich grains such as ooids, pellets, and expanded mica grains, with chemical composition similar to the chlorite rims, seems to indicate a close relation to the chlorite rims. It may be assumed that these chlorite-rich grains and Fe-rich clay were eroded and incorporated in sandy tidal channel facies. Later burial and increase in temperature may have caused redistribution of components, generating chlorite rims. It is possible that a right quantity of chlorite-rich grains and/or Fe-rich clay must be incorporated in the sandstones in order to have porosity-preserving effects, and it is also possible that the tidal channel facies, as opposed to other facies, have had this ”right” amount of chlorite-rich grains and/or Fe-rich clay and thus preserved porosity by development of chlorite coatings. Excessive generation of chlorite seems from chlorite matrix rather than grain-coating rims. Chlorite growth on fibrous illite may also generate pore-filling cement.

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Earlier studies have shown that authigenic chlorite rims preserve porosity in deeply buried sandstones. A large portion of the preserved porosity may, however, be microporosity.

Jensen, Trude (S. Lippard / IKU)

3D-seismisk tolkning av miocene slam strukturer i Sleipner området (Blokk 15/9). 3D-seismic interpretation of Miocene mud edifices in the Sleipner area. (Block 15/9). Miocene mud structures at the base of the Utsira Formation have been studied by interpretation of 3D seismic data in the Sleipner area. Of the 15 mud strcutres interpreted only 3 show indications of being mud volcanoes from the presence of mud outflows in the overlying Utsira sands. It cannot be excluded that the other structures are also volcanoes, but they may be diapirs. A geological model for the mud volcanoes and diapirs is proposed. Comparisons with modern mud volcanoes show similar shapes and sizes to the Sleipner examples, especially when compaction and collapse of the structures under burial are taken into account.

Jonasson, Lina (K.L. Sandvik)

Prøvetaking og analyse av avfall fra Energos ASA. Sampling and analysis of waste from Energos ASA. Confidential The principal goal of this graduation project was to examine what was happening to elements and mass in an incineration process for household and industrial waste. Sampling and analysis was an important part of the work. The analysis turned out to be difficult as especially the raw waste gave off large volumes of potentially explosive gasses during heating. As a result of this work a mass and element balance was made for the plant, which is one of the most complete to date. The work demonstrated that it will take an considerable effort to make a reliable mass/element balance.

Kibsgaard, Anne (K.L. Sandvik)

Regnskap for hydrokarbonkomponenter ved vurdering av bileksos i livsløpanalyser. Accounting for the Speciation of Hydrocarbons in the Evaluation of Automotive Emissions in Life-Cycle Assessment. The work has been carried out in co-operation with the department of industrial design. The topic is the hydrocarbon emissions from the user phase of cars. The primary aim has been to reveal whether or not the inclusion of speciated hydrocarbons would make an important and feasible contribution in Life Cycle Assessment of cars. Application of various impact assessment methods to published measurement data, showed that the current available indices do not support the speciation af automotive hydrocarbon emissions in LCAs. Furthermore, from studying findings regarding factors having an effect on automotive hydrocarbon emissions, the compilation of Norwegian Emission Inventory emission factors seems adequate.

Kvam, Nils-Jarle (K.L. Sandvik)

Industriell utnyttelse av Shredder avfall. Industrial recovery of shredder waste. Current shredding of automobiles leaves a fine shredder waste difficult to process. The waste is therefore put in landfills. The high metal content may give problems with heavy metals in the future at the same time the metals represent a value. A number of different mineral processing techniques were tested out to separate organic fractions and metals. A newly developed air separator gave good results, also on moist fluff, while the more conventional equipment was less promising. The work was carried out together with the Swedish firm Stena- Gotthard Fragmentering.

Kvamme, Tina (T. Malvik)

Forurensninger i fraksjoner av renset kalkstein. Investigation of trace minerals in limestone.

Langen, Håkon (K.L. Sandvik)

Livsløpsvurdering (LCA) av glassflaske i Spania med øko-effektivitets betraktninger. Life cycle assesment of glassbottle in Spain with eco-efficiency conciderations.

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In Andalucia mainly single use throw away bottles are used. In this thesis the effect of reuse bottles are investigated using LCA analysis as the tool for assessment. Not surprisingly a 75 % reduction of environmental impact was found provided a changeover.

Langøy, Birte (K. Nielsen)

Tilpasning av Norsk Hydro U&Ps sikkerhetsstyrings system i forhold til ISO 14001. Comparison of Norsk Hydro E&P Safety Management System in relation to ISO 14001. The task was to investigate to what extent the so called Triple-S EH&S management system developed by Norsk Hydro for their petroleum activities, satisfied the international ISO 14000 series of standards for environmental management. It was found that the Triple-S system only needed minor modifications in order to satisfy the needs of the ISO 14000 series. The project was initiated by Norsk Hydro ASA.

Larsen, Erik (T. Malvik)

Framstilling av database for krom-malmer. Production of a chromium ore database.

Leiknes, Sture (S.O. Johnsen)

Høyoppløselig sekvensstratigrafi i Sandfjordenbassenget ved bruk av georadar, GPR. High-resolution Sequence Stratigraphy of the Sandfjorden Basin, Northern Norway, using Ground Penetrating Radar (GPR). A ground penetrating radar (GPR) survey has been conducted in the Sandfjorden Basin of the Varanger Peninsula, Northern Norway in an attempt to use GPR recordings in sequence stratigraphic analysis. This geophysical method proved to be very useful, producing profiles comparable to seismic reflection profiles, but with a much higher resolution. Penetration varies , but is generally found to be very good, and along some favourable profiles the penetration depth exceeded 40-45 m. An antenna frequency of 50 MHz proved to be most adequate, with a vertical resolution close to 1 m. 100MHz recordings were carried out along some profiles to increase the resolution and produce more detailed profiles. The Sandfjorden Basin has been strongly influenced by a postglacial isostatic rebound related to the Late Weichselian ice sheet, resulting in uplift of the crust (rebound outpacing the additional eustatic se-level rise). The basin experienced consequent forced regression of the shoreline and deposition of an accretionary forced regressive sedimentary succession. Sedimentary filling (14.500 B.P. to present) of the basin is associated with high sediment supply related to a glaciomarine fan delta. The present topography of the basin constiutes a modern 6th order sequence boundary. Several 7th order sequence boundaries splay off from this surface and divide the sedimentary succession into a hierachy of units. The sequence stratigraphic investigation has revealed a total of four different 7th order sequences. These are again comrised of a total of 24 units representing 8th order sequences, which again can be decomposed into a total of 55 9th order sequences. This high-frequency sequence stratigraphy reveals cyclicity in the century range, with sequences deposited during a time span of approximately 200 years, and a shoreline extension in the order of 30-50 m. In addition, it is possible to notice different systems tracts within 9th order sequences. The sedimentary succession of the Sandfjorden Basin can be divided into four main sequences (7th order) divided by important surfaces like the Younger Dryas ravinement surbroface and the Tapes transgressive surface of marine erosion. Construction of maps, illustrating bedrock topography, sediment thickness, clinoform distribution and several chronostratigraphic diagrams has provided powerful insight in the evolution of the Sandfjorden Basin.

Leistad, Øyvind (T. Myran)

Internkontroll ved næringsparker. Integrated SHE-management for renters in a pile of buildings.

Liu, Xinjian (E. Broch)

Stability analysis of the slopes at intake tower, Baise multipurpose dam project, P.R. China

The slopes at the intake tower at Baise are composed of rocks of various types and have maximum heights of 100 m. For the analysis of the stability of the slopes stereographic projection is performed to identify potential failure modes. Numerical analyses using the Universal Distinct Element Code (UDEC) have been performed to reveal the mechanism of the stability problems. The study indicates that potential wedge failure is possible for both the tunnel face slope and the east side slope. The excavation design appears feasible. The rock support reduce the deformation of the slope, but not

70 Institutt for geologi og bergteknikk Hovedoppgaver 2000 much. Due to jointing and high degree of weathering, one must be prepared for local stability problems. Support during excavation is recommended.

Lyatuu, Arthur Edwin (Lippard / Tjåland)

Seismic interpretation in Kisangire Area. Miocene mud structures at the base of the Utsira Formation have been studied by interpretation of 3D seismic data in the Sleipner area. Of the 15 mud strcutres interpreted only 3 show indications of being mud volcanoes from the presence of mud outflows in the overlying Utsira sands. It cannot be excluded that the other structures are also volcanoes, but they may be diapirs. A geological model for the mud volcanoes and diapirs is proposed. Comparisons with modern mud volcanoes show similar shapes and sizes to the Sleipner examples, especially when compaction and collapse of the structures under burial are taken into account.

Mittal, Sandeep (E. Broch)

A study of the tunnel and underground powerhouse for Teesta V hydro-electric project, Sikkim, India. Different layout designs commonly used in Norway have been considered for design of the 17.8 km headrace tunnel, the pressure shaft and the powerhouse. A FLAC-3D numerical study of the powerhouse complex has also been carried out The tunnel system has been realigned and the number of adits reduced from 5 to 3. Both headrace tunnel and pressure shaft have been redesigned as mainly unlined with concrete lining limited at certain locations with shear zones and weak zones. By optimizing the shape of the powerhouse cavern the span may be reduced. The numerical model studies indicate that the deformation of walls is much higher than the deformation at the crown The major principal stress is tensile near the walls locally and it implies that the loosened state of rock mass near the wall should be supported with adequate rockbolts and shotcrete.

Moseid, Mari (B. Brattli)

Utlekking av PAH fra marine sedimenter fra Trondheim havn. Leaching of PAH from Habour Sediments from Trondheim havn. Trondheim Havn A/S wishes to use dredge sediments from the Harbour as infill in the extension of Pier 2. Scandiaconsult AS has made a risk analysis on harbour fill at the location, and their conclusion was that Polycyclic aromatic hydrocarbons (PAH) will leach into the sea from the fill. The amount of leached PAH will, however, be so small that there is no rick that the leached PAH will have any negative environmental effects. The transport of PAH is calculated from the total contents of PAH in the matrix. These calculations do not consider the influence of temperature and salt content. In order to investigate these influences, leaching tests have been carried out. Samples have been collected in areas where Trondheim Havn AS wishes to dredge. The sampling was performed by GeoCore AS and the author. Samples from different locations were mixed to form one large integrated sample. Different leaching tests were made on this large sample: four Serial Batch Tests and four Availability Tests. The Serial Shake Tests consisted of two tests with synthetic salt water and two tests with acidified fresh water. The tests were made at 7ºC and 20ºC. The leachates were analysed for PAH (EPA 16). It was also decided to performe a Column Test, but it could not be performed due to the nature of the sample and lack of time. The results from the Availability Test did not give the total availability for PAH in the sediment. The Serial Shake test indicates that leaching with synthetic salt water is lower than leaching with fresh water. The temperature gave minor effect on the leachate with synthetic salt water, but there was a large effect on the results of the fresh water tests. From the final results it is possible to conclude that both temperature and salt water influence on the leaching.

Moskvil, Øystein (T. Myran)

Internstyringssystem for en databedrift. Integrated SHE-management for a computer firm.

Müller, Kjell (K. Nielsen)

Blokkformatering av blokker i larvikitt. Boring kontra sagling. Boring kontra saging ved uttak av primærblokk.

Nordfjord, Sylvia (S.O. Johnsen)

Smørbukkfeltet: Et studie av trykkregimer og forsøk på identifikasjon av mulige strømningsbarriærer. The Smørbukk Field: A study of pressure regimes and the attempts to identify possible flow barriers.

71 Institutt for geologi og bergteknikk Hovedoppgaver 2000

The Smørbukk field have producible hydrocarbons in the lower Jurassic Tilje formation. This formation consists of interbedded layers with strong permeability contrasts, reflecting high heterogeneity of the different sub-layers. The Smørbukk field has internal pressure barriers indicated by hudrocarbons of different composition being locked in compartments. The aim of this study was to identify potential pressure barriers in the Tilje Formation. The barriers were identified by using repeated formation tests (RFT) and Drill stem tests (DST), for all the exploration, production and injection wells drilled before September, 2000. The RFT data were interpreted ub pressure/depth plot for each zone, where the reservoir connectivity between the wells was indicated by pressure points laying at the same gradients. Emphasis was laid on to understand pressure trends and communication within the Reservoirs units. Available pressure data was used to investigate fluid pressure communication in combination with structural geological, geophysical and geochemical studies for confirmation of common pressure regimes and compartmentalisation. The compartment boundaries are believed to represent different pressure barriers which is important to map in order to understand the sealing mechanism of the Smørbukk Field. The locations of the potential barrirs were changing for the different zones, and this is making the reservoir zones in the Tilje Formation very complex and heterogeneous. The potential barriers as defined in this thesis are different from earlier segmentation studies, by defining more and different boundaries within each reservoir zone. The Smørbukk Field seems to be relatively structurally simple, and the pressure barriers appear not to be structurally controlled. On the other hand, the Tilje Formation is sedimentological and diagenetical complex, and it is therefore possible that compartmentalisation to large extent is due to progressive burial diagenesis of sandstones and siltstones and to frequently lateral variation in the facies.

Rasmussen, Elisabeth (E. Broch)

3D-modellering av terrenget på Høvringen. 3D-modelling of the Høvringen area. Information about topography and geology may be easier to understand when presented in a 3D model. Mistakes in the interpretation may be avoided. The thesis describes the visualization of the terrain at Høvringen in Trondheim. Included in the 3D model is also the caverns for the underground sewage treatment plant.

Remme, Ingunn (S. Lippard)

Trykk- og migrasjonsmodellering i Sleipner området ved bruk av forskjellige forkastningsforseglingsmodeller. Pressure and migration modelling in the Sleipner area with use of different faultseal models.

Rigland, Kristina Merethe (S.O. Johnsen)

Modellering av hydraulisk oppsprekning i sedimentære basseng. Modelling hydraulic fracturing in sedimentary basins. Hydraulic leakage in the Northern Viking Graben is investigated by use of the PRESSIM simulator developed by Hans Borge at Sintef Petroleum Research. Different failure criteria are discussed. The simple failure criterion that the cap-rock will leak formation fluids when the pore pressure reaches a value close to the minimum principal stress was implemented in PRESSIM (Borge, 2000). Different methods for estimating the minimum principal stress ha sbeen tested: Breckels and van Eekelens (1982) empirical model, the minimum principal tress as a function of the vertical stress and Grauls‟ (1999) model based on the tectonic regime of the basin. The results of the simulations indicate that a second-order curve describes the evolution of the minimum principal stress adequately and that this curve should be calibrated according to the tectonic setting of the basin in which the simulations are conducted. Two of the compartments in the study area are modelled to leak formation fluids at realistic values of the minimum principal stress. Both compartments, the Gullfaks compartment and the Gullfaks South compartment, act as regional drains for formation fluids in the area and both compartments contain hydrocarbons.

Rødseth, Stein Vegar (B. Nilsen)

Numerisk analyse av bergsikring. Numerical modelling of rock support.

72 Institutt for geologi og bergteknikk Hovedoppgaver 2000

Numerical analyses of the effects of various types of rock support in tunnels have been carried out. Main emphasis has been placed on analyzing the effect of reinforced shotcrete ribs as alternative to cast in place concrete lining. The Frøya subsea tunnel, where both these support alternatives have been used, and comprehensive convergence measurements have been carried out, has been used as relevant case and calculation example. Only small differences in deformation was found between the two alternatives. It is concluded that the biggest difference between the two support alternatives is the greater flexibility of the alternative with reinforced shotcrete ribs.

Sanjeev Kumar Thakur (B. Nilsen / Statkraft Anlegg)

Excavation and stability of pressure shaft - A case study based on Khimti Khola Hydropower Project, Nepal. Inclined shafts are key elements of hydropower projects, and major problems will be the result of any shaft failure. The intentions of this thesis have been to evaluate excavation methods, rock support and potential stability problems of pressure shafts first on a general basis, and then to discuss in detail the incidents during excavation of the pressure shaft at Khimti Khola hydropower project in Nepal. It is discussed what could possibly have been done to prevent the shaft failure at Khimti, and what should be done in the future in Himalayan rock conditions to avoid such incidents. The main conclusion is that thorough investigation in preconstruction phase as well as construction phase investigations are the key issues for obtaining a good result.

Steingrimsson, Jon Haukur (B. Nilsen / Landsvirkjun)

Kárahnjúkar Kraftverk, Ingeniørgeologisk og anleggsteknisk analyse. Kárahnjúkar hydropower project, Rock engineering analysis. As part of Kárahnjúkar hydropower project in Iceland, about 40 km of diameter 7.2 m TBM tunnels are planned. In this work, detailed analyses of the feasibility, technical complexity, scheduling and cost of the TBM tunnels have been carried out. Particular emphasis has been placed on analysing the significance of so-called “mixed-face conditions” for performance prediction. In the discussion of mixed face conditions, relevant data from other projects in similar geology are also included. As basis for the evaluation of Kárahnjúkar, geological information and reports from pre-investigations have been available from Landsvirkjun, and field survey, sampling and laboratory boreability testing have been carried out by the candidate. Predicted net penetration according to the NTNU prognosis model is 3.2 m/h, corresponding to a gross advance rate of approximately 130 m/week.

Stenvold, Jørgen (A. Myrvang)

Tektonikk i Svea-Nord-området, Svalbard. Tectonics in the Svea-Nord-area, Svalbard. This thesis is the result of a joint project between the Norwegian University of Science and Technology and Store Norske Spitsbergen Kulkompani AS. The main objective of the thesis is to evaluate possible tectonic disturbance of importance for the mining system in the Svea Nord mine, Svalbard. Field data was collected underground in the Svea Vest and the Svea Nord mines and in mine no. 7 near Longyearbyen. Field data was also collected in the glacial areas covering the Svea Nord mine. The investigations show that two sets of structures dominate the eastern part of the tertiary Central Basin. These are compressional structures oriented NNW- SSE and extensional structures oriented ENE- WSW. The compressional structures consist of fold and thrust faults and indicate that structures observed in the Svea Vest mine continue northwards through the Svea Nord mine. However, the compressional structures seem to be less developed in the Svea Nord than in the Svea Vest mine. The extensional structures consist of sub- parallel joints and normal faults. Six normal faults with throw between 1.5 and 4.7 meters were mapped in the Svea Nord mine. However, due to their strike they will not affect the future mining system. To predict faults further north in the Svea Nord mine, most boreholes in the Svea Nord area were correlated. The correlation indicates 5 normal faults which all are sub-parallel with the faults observed in the southern part of the mine. The faults seem to have throws between 3 and 15 meters. The observed and predicted structures can be explained by the established theory that Greenland in tertiary time drifted northwards in relation to Svalbard. This caused transpression along the western coast of Spitsbergen. The transpression was firstly dominated by compression that was transmitted to the east by décollement zones in ductile paleozoic and mesozoic rocks. Therefore the compression did not only affect the western coast, but created slickensides, folds and thrust faults also in the eastern part of the sentral basin. Later on the transpression caused pronounced strike- slip movement along old lineaments on Spitsbergen. This movement created extension in a NNW- SSW direction and resulted in the observed normal faults.

73 Institutt for geologi og bergteknikk Hovedoppgaver 2000

Vikhamar, Petter (R. Sinding-Larsen / Sintef Petrol.forskn.)

Multilags hydrokarbon-migrasjon i Vøringsbassenget. Multilayer hydrocarbon-migration in the Vøring Basin.

Aasen, Reidun (B. Brattli / NGU)

PCB i prøver av jord og marine sedimenter i Trondheim – typer og kilder. PCB content in soils and marine sediments from Trondheim – types and sources. The administration of the City of Trondheim has in co-operation with local harbour authorities and the county governor (Trondheim Havn and Fylkesmannen i Trøndelag) initiated a project to map contaminated soils and sediments in the city and harbour of Trondheim. The city‟s goal with this project is to deal with topics of contaminated ground and sediments in a way that is both economically and environmentally secure. Samples from soils (262) and samples from marine sediments (41) has been collected during the project. The preparation and interpretation in this thesis are based on PCB analysis of these samples. Polychlorinated Biphenyls (PCBs) are a group of chemical compounds that consists of two phenyl modules and a connection of various chlorine atoms (from 2-10) to the biphenyl. Human exposure of PCB can cause cancer. disturbances in reproduction and reduction of the immune system. Production of PCB was prohibited in 1980. PCB has been used in electrical systems, oils, liquid- and gas systems, paint, plastic and construction products among others. A lot of this has leaked out to the environment. But there is still a large amount of PCB left in many products produced before 1980. It is important to find the sources for PCB pollution to stop further dispersion. A method based on profiles from the analysis of seven congenes is used in this thesis. The profile of each sample is compared to the profiles of technical PCB mixtures. In that way it is possible to identify the type of PCB in a sample and determine its PCB source. Compared to marine sediments the results show that samples of soils are generally less contaminated by PCB. Most of the soil samples show no trace of PCB. The anomalies are scattered throughout the investigated area. The PCB pollution both on land and in the harbour consists mainly of high chlorinated types. In addition two low chlorinated PCBs are found on land. None of the marine sediments consists of low chlorinated PCBs. Generally the contamination of PCB in Trondheim shows an increase of quantity and complexity from east to west. The areas around Nyhavna and Nidelven contain few types of PCB and a larger share of the contaminated samples consists of pure Clophen mixture. Ilsvika is the most complex PCB contaminated area in Trondheim. A connection between PCB sources on land and contamination in the harbour is likely. This conclusion is based on a relatively small amount of samples of soils around the harbour and is therefore not certain.

Aasly, Kurt (K. Sundblad)

En petrologisk undersøkelse av gull mineralisering på Ringvassøya, Troms fylke. A petrological investigation of gold mineralization at Ringvassøya, northern Norway. The Ringvassøy greenstone belt has since long been known for its gold occurrences. In the early 1980‟s, two exploration parties carried out gold survey on the island , but both projects terminated and the clains were abandoned in 1985. The greenstone belt was previously considered as Early Proterozoic. However, recently Motuza et al. (in prep.) has demonstrated that the greenstone belt is Archean (-2.84 Ga). The Holmevasshøgda area, west of Dåfjord in the northern part of the island, is one of the most interesting targets for gold exploration, on which this diploma thesis has concentrated. The bed rock in the Holmevasshøgda area is dominated by a metamorphosed mafic volcanic unit which is crosscut by a E-W trending fault- or fracture, observed as an approximately 5 meters wide topographic low along Litleelva. This zone is presumed to represent a wider (up to 50- 100 m) fault zone. The metamorphosed mafic volcanic rocks are cut by several metamorphosed, mafic, porphyritic diabase dykes of tholeiitic magma of subalkaline basaltic geochemistry, which also cross-cut the E-W striking fault. The diabase dykes are partly sheared as a result of later movement in the fault zone. The main unit has been influenced by shearing and hydrothermal- and metasomatic alteration, hence the composition and general characteristics of the rocks vary. The metamorphosed mafic volcanic unit contains varying amounts of quartz- and carbonate veinlets. This may have been caused by the fault zone that cuts through the Holmevasshøgda area. The origin of the anomalous gold contents in till and soil samples were never found by previous prospectors. This might be because all previous surveys have concentrated on the main lineament along Litleelva, striking eastwards from Holmevasshøgda towards Dåfjord. Instead of concentrating on one particular feature in the topography, detailed work should be carried out with regard to deep overburden soil sampling across the area, and detailed structural geological mapping to learn more about the entire fault zone and not only isolated parts of it.

74 Institutt for geologi og bergteknikk Hovedoppgaver 1999

1999

Austefjord, Inger (K. Sandvik / S. Lydersen)

Miljørisikoanalyse for offshore virksomhet i Mexicogolfen. Environmental risk analysis for the offshore petroleum activity in the Gulf of Mexico. Statoil is doing exploratory drilling in the gulf of Mexico. Statoil is, as stated in company policy carrying out risk analysis in all operations, in Norway this is required by the authorities but is not required in the US as such analysises is carriied out at a field level by the authorities themselves before any permissions are granted. A qualitative analysis is carried out in the thesis. Legal problems restrict the usefulness og a quantitative analysis in the US. In the thesis the possibilities and advantages/disadvantages of carrying out similar risk analysis as is usual in Norway is discussed.

Berg, Thomas (A. Myrvang)

Numerisk modellering som et hjelpemiddel for planlegging av bergrom. Numerical modelling as a tool for designing and planning of rock caverns. Using the Raubergvik underground olivin mine as case, a large number of possible mining layouts are modelled by UDEC 2-D numerical modelling. The results are partly used in a work by Murstam for more detailed planning of the mining system. A major conclusion is that it is the stress level and not the deformations that are important for the stability evaluations in this case. The olivin and many other rocks are so stiff that the deformations regardless will be very small.

Breirem, Kjersti H. (R. Sinding-Larsen)

Oppdatering av funnsannsynligheter for prospekter i en letemodell som følge av funnresultater. Updating of prospect discovery probebilities in a play given the outcome of the exploration drilling.

Chitrakar, Pushpa (E. Broch / NORAD)

Khimti I Hydropower Project - Tunnel support systems, anticipation and reality. The Khimti I project is under construction in Nepal and consists of 12 km of tunnels and an underground powerhouse. The rocks are different types of geisses and schists. Difficult weakness zones have strongly influenced the tunnelling works. The thesis gives a critical evaluation of the preinvestigations carried out for the project and compares the anticipations made with realities experienced in the tunnels. Also the influence of the managment on the tunnelling results are discussed.

Ellefmo, Steinar L. (R. Sinding-Larsen)

Evaluering av ressurspotensialet innen Øvre Jura letemodellen i den sydlige del av Nordsjøen med spesiell vekt på den sub-letemodell som inneholder Ula og Gyda feltene med tilhørende prospekter og leads. Resource evaluation of the Upper Jurassic play in the southern North Sea with special emphasis on the sub-play covering Ula and Gyda Deposits including adjacent prospects and leads.

Engjom, Håvard (A. Myrvang)

Dimensjonering og driftsopplegg for rom og pilarbryting i en del av Svea Nord. Dimensioning and design of a room- and pillarfield in the southern part of the Svea Nord Mine, Svalbard. Based upon available information from the operating Svea Vest coal mine, a room and pillar field is planned and designed in a part of the possibel Svea Nord mine. Different layouts are discussed from rock mechanical, operational and economical points of view.

Foyn, Sven Erik (S. Lippard)

Strukturelle rekonstruksjon av paleovanndyp i Vøringbassenget. Structual reconstruction of paleobathymetry in the Vøring Basin A key regional seismic line across the Vøring Basin was interpreted and depth-converted. A layered model was built for the purpose of structural reconstruction and lithologies assigned to the layers. The purpose of the modelling was to reconstruct paleobathymetry from the Coniacian to the present day. The units were restored using either deep marine infill or prograding scenarios. The results show a deep water basin in the Coniacian and Campanian, shallowing in the Maastrichtian-Danian to near zero water depths. Increasing water depths occur towards the late Eocene and then

75 Institutt for geologi og bergteknikk Hovedoppgaver 1999 decrease again towards Miocene. During the Pliocene, a dramatic increase in water depths took place which continue to the present day.

Forssell, Heidi (K. Sandvik):

Undersøking av betong i forbinding med riveprosjektet RIT 2000. Evaluation of concrete related to the demolition project RIT 2000. This thesis examines first the requirements of recirculated concrete. There are not much done on the standardisation side on this yet in Norway. Relevant data had therefore to be found from foreign sources and also from virgin aggregate standards where applicable. On this basis the concrete from a pilot demolition project was sampled and examined in the laboratory. The concrete examined was too high in alkalis, otherwise it could be used together with low alkali cement as aggregate for new concrete at least for less demanding purposes.

Gilhuus, Mette J. (K.L. Sandvik)

Innføring av ny renovasjonsordning i Drammensregionen – adferdsendring og måloppnåelse. Innlevert jan.99. Implementation of new Renovation System in the Drammen Region – Change of behaviour and goal achievement. A new selective garbage collection system is implemented in the Drammen region of Norway. A critical factor to obtain a good result is public co-operation as well follow up by the collection crews. In this work the selective collection has been monitored by interviews and by following the crews. The selective collection has generally been successful with about 60 % material recovery from households compared to 18 % in 1996.

Greiff, Siri (K.L. Sandvik)

Evaluering og optimalisering av deponigassanlegget på Heggstadmoen. Evaluation and optimalization of landfill gas plant Heggstadmoen. The Hegstadmoen plant is operated over a number of wells. Some are bad some good. The candidate went over the wells and did a job to find which ones were performing well and which ones were not. Some of the bad wells were flooded with groundwater. Ellimination of the poorer wellsw improved performance.

Hansen, Elin Anita (K.L. Sandvik)

Forbedring av kondisjonerings- og avvanningsprosesser ved lysbuebehandling. Enhancement of conditioning and dewatering processes by electrical arc Pretreatment. Reducing the volume of biosolids and other residuals is one main objective in wastewater treatment. More efficient technologies are called for t improve the efficiency of such operations. This study was carried out at the University of Delaware, Newwark USA as part of a larger ongoing project using electrical arc treatment methods to improve dewatering.

Hanssen, Geir (B. Brattli)

Grunnvannskvalitet i fjellbrønner på Værøy. Innlev. Mars 99. The quality of water in hard-rock wells on Værøy. This diploma is done in connection with a collaboration between the minicipality of Værøy and the Geological Survey of Norway, and deals with the hard-rock wells that makes up the waterworks of Sørlandet on Værøy. These wells are described both physically and chemically, and based on this descriptions suggestions will be made for a better way of running the wells. The field of wells is sited in grey gneis that are very fractured in the upper part. Over the rock we find a thin layer of hummocky ablation moraine and marsh. For the recharge to equal the withdrawal we need about 1,5 % recharge in hardrock, and 13 % moraine. For this wells running the water quality is good, and the wells 9, 10 and 12 is closed because of poor quality. The capacity of the wells on Værøy is higher than comparable values. This is due to the storage capacity of the highly fractured rocks surface and the gravel at the end of the steep slopes. To get the needed amount of water to the island, it is suggested that the wells 4, 8, 13 and 17 are put back in production, if possible. If these wells have the requested quality it should be possible to withdraw 1500 m3 a day.

76 Institutt for geologi og bergteknikk Hovedoppgaver 1999

Hatlebakk, Ragni Must (K. Rokoengen)

Glasialgeologi og seismisk stratigrafi i Beistadfjorden, indre Trondheimsfjorden. Glacial geology and seismic stratigraphy in Beitstadfjorden, inner Trondheimsfjorden, Central Norway. On the basis of shallow seismic lines in Beitstadfjorden, the Quaternary stratigraphy has been interpreted. Three till units have been identified above bedrock, with a total thickness of up to 195 ms. Most of the till thickness is located in a sixteen kilometers long and one to two kilometers wide trench caused by glacial erosion in bedrock. The trench follows the general trend of the fjord, NE-SW. The till units are most likely of Mid- to Early Weichselian age, although a Late Weichselian age related to a Younger Dryas ice advance can not be ruled out. The clays has most likely been deposited during the Late Weichselian deglaciation. The thickness of Holocen sediments are assumed to be rather small, probably less than 5 milliseconds.

Hugdahl, Anna Kristina (T. Malvik)

Zetapotensialet av jernoksidpigment. Zetapotential of iron oxid pigments. The thesis has been carried out in co-operation with Rana Gruber. Samples from different iron oxide pigments were investigated in order to determine the surface properties of the particles expressed by the Zeta potential. The laboratory work was carried out using the Coulter DELSA 440 SX, recently being installed at the chemical laboratory of the department. Procedures how to make the analysis were established and the reproducibility of the instrument was tested.

Ingebrigtsen, Elise (S.O. Johnsen)

Oppskalering av porøsitet i horisontale brønner. Upscaling porosity in horizontal wells. A successful prediction of reservoir behaviour under any scheme hinges upon our ability to provide a realistic description of reservoir geology at the scale which important variations of rock properties can be captured. The objective of this thesis is to define, test and improve the methodology for upscaling porosity and permeability in a horizontal well. No automatic procedure is available for upscaling properties from a horizontal well to a geological model, and subsequently to a flow simulation model. To gather information about the lateral facies variations and porosity distribution of chalk before the upscaling, the core from the horizontal well should be examined closer. The upscaling demands a precise study of the well data, of vertaical and lateral trends and the area around the well before creating of the fine model. Subsequently a stepwise improvement of fine models with focus on the previous results should be performed. In the current study the IRAP/RMS Reservoir Modelling Software was used. An evaluation of wether vertical and horizontal heterogeneity and trend of horizontal well is adequately captured in fine model is needed after each upscaling. If the model not honours the requirement in the evaluation, the modelling procedure in IRAP/RMS has to be repeated. Finally, when an upscaled fine model achieve satisfactory results, the permeability modelling may be performed based on crossplots between permeability and porosity. The procedure for upscaling a geological model to a coarse flow model requires a good correspondence between the fine and the coarse grid constructions. Subsequently, an exact layer correspondence in the sampling definition will achieve the best results. Arithmetic average gives the most correct results for porosity upscaling, and flow based calculation gives the best results for permeability upscaling. A correspondence between volumetrics of the fine and the upscaled coarse model is required. If the correspondence between the fine and the coarse model is not satisfactory, the upscaling procedure is reviewed and altered as necessary.

Jayawickreme, Dushmantha H. (S.O. Johnsen, MSc)

Fault sealing processes applied to basin modelling. Petroleum exploration in faulted basins is still a formidable challenge, even in the mature provinces like the North Sea. Structural, lithological and stratigraphic conditions have been found to be strongly controlling the migration and accumulation or seepage of petroleum resources to and from the fault compartments in these basins. Faulting either of meter scale or minute, in millimeter scale can create considerably low permeability barriers for fluid flow. These low permeability barriers or seals, their origin and distribution along fault zones are still not clearly known. Hence, basin scale fluid flow modelling in faulted basins, where seals are the most fundamental is largely based on empirical relationships and assumptions. Fault zone characteristics are a function of fault geometry, lithology, stratigraphy, tectonic and

77 Institutt for geologi og bergteknikk Hovedoppgaver 1999 subsidence histories. However, due to the large variability encountered in well studied fault zones, defining a single model that can be applied to all the situations has so far nor come about. The work discussed here concentrates on factors controlling sealing potential of faults and on a transmissibility model developed for basin scale fluid flow modelling in faulted basins. The model was applied to the North Viking Graben area of the North Sea, to analyse wether it is in fact necessary to include all the known fault sealing processes and parameters in a model, in order to obtain a realistic pressure map over a basin. The modelled results and subsequent analysis indicate that this may not be to a certain extent, but there are some exceptions where sealing processes may be the most likely reason for observed deviations between actual and modelled pressure in the North Viking Graben area.

Karlsen, Lars Christian (B. Nilsen)

Miniatyrtester for borbarhetsundersøkelser. Miniature tests for boreability evaluation. The feasibility of miniature testing for boreability estimation has been studied. As background for the study, a review of relevant methods for boreability testing has been made based on available literature. A representative selection of rock samples have then been collected, and boreability testing has been carried out according to “traditional NTNU procedure” and based on miniature testing. Promising correlation between standard and modified boreability testing has been found, although further correlation study is required for the miniature testing to become fully reliable.

Kjørmo, Gro Røst (B. Nilsen)

Skråningsstabilitet i Tellnes Dagbrudd. Rock slope stability at Tellnes open pit mine. Based on review of available background material, field mapping and theoretical analyses, rock slope stability at Tellnes open pit mine in Southern Norway has been evaluated. During field mapping, main emphasis has been placed on character and orientation of discontinuities relatively to the slope face. Field and laboratory testing has been carried out for estimation of joint friction. The open pit mine has been divided into design sectors, and maximum slope angles have been proposed for each sector. Stabilizing measures, such as drainage, have been proposed, and also a system for monitoring/stability control.

Langelid, Audun (A. Myrvang)

Undersøkelser vedrørende forsering av en forkastningssone i Dalen gruve. Investigation concerning planned tunnelling through a subsea fault zone in the Dalen limestone mine. Based on surface and underground field mapping, and available data from the operating limestone mine, a suggestion is made how to cross a major fault zone in a safe and economical way. The potetial crossing locations are situated sub- sea, and control of leakage is therefore paramount. A comprehensive rock support and pre-tunneling grouting is outlined.

Maganga, Gerald M. (S.O. Johnsen, MSc)

The distribution and depositional environments of the Silkesand, Gullfaks Field. Well log correlation and thickness mapping of the stratigraphic units, have demonstrated the precence of the anomalous thick, elongated and massive sedimentary unit (Silkesand) in the Tarbert formation at the Gullfaks Field. The Silkesand is interpreted in terms of base-level fall, valley incission and later fluvial and tidal infilling accomanied by synsedimentary faulting at the valley margins. In summary the Silkesand have the following distinct characteristics: 1) It is elongated, channel like geometry; 2) Anomalously thicker than the laterally juxtaposed lithostratigraphic units; 3) It has an erosive base and non correlatable to the surrounding sediments; 4) It is clean and corse grained sand. The valley infill shows no distinct differences between the lower fluvial and the upper tidal infill.

Mellgren, Stein Ove (K. Nielsen)

Driftsplan for utvidelse av bruddet på Steinskogen. Operation plan for expansion of the quarry at Steinskogen. The task was to develop a new mining plan for the Steinskogen quarry of Franzefoss Bruk AS. The new mining plan was needed because the quarry has had to re-evaluate their reserves due to changing market demands that had rendered some of the original reserves less suitable for production. The new mining plan consisted of a general quarry lay-out, and a plan for production sequencing with regard to haulage optimisation in the quarry.

78 Institutt for geologi og bergteknikk Hovedoppgaver 1999

Murstam, Lars Runar (K. Nielsen / A. Myrvang)

Planlegging av underjordsdrift i Raudbergvika olivingruve. Planning of underground mining at the Raudbergvika olivine mine. The thesis work was done in connection with developing an underground mine at the Raudbergvika olivine deposit. The deposit has been operating as a quarry for more than 15 years, but in order to ensure continuos production capability also during winter, the company wanted to establish an underground operation. The underground design was based on a rock mechanics analysis by UDEC modelling in order to determine feasible dimensions of the stopes. The work also consisted of an economic assessment of development work and underground production in the new mining area. The work was done as part of a co-operation project with Industrimineraler AS.

Opsahl, Christian (S. Lippard)

Tertiær inversjon av Helland Hansen-domen. Innlev. Juni 99. Tertiary inversion of the Helland Hansen Arch. The Helland Hansen Arch is a compressional anticline which shows a multi-phase growth history. The timing and causes of the Tertiary inversion history are determined by interpretation of seismic data, isochron maps and decompaction curves. Two major compressional events are recognised in the early Eocene and late Oligocene-mid Miocene. The later event was of greater magnitude than the earlier. The overall compressive stresses can be explained by spreading in the adjacent ocean (ridge push forces). The two events can be related to periods of increased sea floor spreading and, in the case of the later event, the emergence of Iceland situated on the mid-ocean ridge.

Saran, Vijai (E. Broch / NORAD)

Three dimensional numerical analysis of underground works at Xiaolangdi multipurpose project in China. This thesis analyses the stability of the underground powerhouse and other adjacent caverns by carrying out 3- dimensional numerical analysis by the FLAC-3D code. Elastic and plastic material models have been used. The results are compared with 2D analyses. Some of the conclusions are that the deformation of walls are much higher than for the crown, predictions by the 2D analyses are higher than for the 3D analyses, there is no justification for provision of 25 m long cable anchors in the crown.

Sjaastad, Hege (S.O. Johnsen)

Seismisk karakterisering av et kanalkompleks på kontinentalskråningen, inkludert litologisk prediksjon. Seismic characterization of a slope channel complex including lithology prediction. The deep-water area offshore the Niger delta represents a frontier province for hydrocarbon production. Depositional processes that transports sand to the deep-water environment are not yet fully understood. A sequence in the younger deposits has been interpreted as an attempt to understand what processes have created these deposits. These results can be used to predict what reservoirs and where they are located in respect to the delta front at depths where hydrocarbons are accumulated. The study area is at the base of the slope where gradients are relatively steep. The study reveals a channel belt trending in a NE-SE direction. High-density turbidity currents initiated by longshore currents on the shelf are bypassing and deposited further basinward, while low density turbidity currents have slope-centered deposition. The latter have caused sediment plugging of the channels. A combination of these events have created a depositional system clasified as a mixed mud/sand rich system with multiple sources.

Snilsberg, Brynhild (K. Sandvik)

Utvikling av prosess for utsortering av våtorganisk fraksjon (hovedsakelig matavfall) fra blandet husholdningsavfall/kommunalt avfall. Development of a process to separate wetorganic fraction (mainly foodwaste) from untreated domestic waste. Confidential A trommel screen was constructed to separate the food from the rest of the waste. The effect of the process was monitored as an effect of such factors as screen opening, screen inclination, retention time and feed rate.

79 Institutt for geologi og bergteknikk Hovedoppgaver 1999

Øvrebø, Lena Kristine (S. Lippard)

Forover modellering av de kretasiske avsetningene i nordlige Nordsjøen. Forward modelling of the Cretaceous deposits in the North North Sea. DEMOSTRAT software is used to model the Cretaceous deposits of the northern North Sea. An attempt is made to reproduce the geometry of a structural reconstruction along 60oN. Values of subsidence rates that best reproduce the geometry are chosen as input data. The study shows that there was subsidence throughout almost the whole Cretaceous, with the exception of uplift of the intrabasinal high separating the Horda Platform and Viking Graben in the early Cretaceous. Rates of subsidence accelerated in the Cenomanian. In the Maastrichtian there was uplift or only minor subsidence. The modelling suggests that mass-flows may have been a significant process in the early Cretaceous, especially in the Viking Graben. No mass flows occurred on the Horda Platform where gradients are much lower.

Wolff, Anke (S.O. Johnsen)

Draupnereservoaret i Oseberg syd området - kvantitative aspekter av geologiske usikkerheter relatert til en liten, hydrokarbonførende struktur. The Draupne Reservoir of the Oseberg Syd area - quantitative aspects of geologic uncertainties, related to a small hydrocarbon bearing structure. Considerable uncertainty is related to the turbidite reservoir in the Draupne Formation on the Omega south structure of the Oseberg Syd field, Northern North Sea, which has been penetrated by one well only. Two depositional models propose a confined fan or channel-like geometry as the deposition most probably was influenced by syn-sedimentary rotation of the Omega South fault block. Based on these depositional models 2.5D- and 3D-reservoir modelling has been performed. Structural 6-layer models and parameter models based on thoroughly evaluated petrophysical properties have been generated. High resolution 3D-facies models have been created, distributing 9 facies-types, using well data and facies geometry statistics. Petrophysical parameters were modelled based on constant average values per facies. The 2.5D- and 3D-parameter models were sampled and up-scaled to coarse simulation grids respectively. For all reservoir models volumetrics resulted in half of the STOOIP-estimates compared to earlier results. Differences are mainly explained by the depositional model. The resulting 3D-facies models of the Draupne reservoir displayed a more realistic reservoir complexity than the 2.5D-layer models of this and earlier evaluations. This thesis not only underlines the need for detailed geological modelling and accurate resrevoir characterisation but also shows how the 2.5D- and 3D- modelling approaches supplement each other. By this combination consistent results have been achieved.

Wærp, Silje (K. Nielsen)

Ombruk av tegl- på Lilleborgprosjektet. Demolition and reuse of bricks on “Lilleborg”. A former chemical industrial complex in Oslo, Lilleborg, is being demolished and redeveloped for residential use. The property a contains a number of different buildings of varying ages and different constructions. The developer had been ordered by the authorities to maintain some of the original exterior features which consisted of old brick work. This made it necessary to recycle a substantial quantity of old bricks in buildings that where being demolished. The objective of the thesis was to document the demolition work, including the subsequent cleaning and handling of old brick in preparation for re-use. The work also encompassed an economic assessment of the undertaking, comparing it with regular demolishing and depositing of old brick construction materials, and replacing them with new bricks. The work was done for NCC Anlegg AS.

Aasheim, Harald (K. Nielsen)

Håndtering av asbestholdig avfall på deponier. Handling of asbestos waste in landfills. The thesis work was done in order to investigate the handling of asbestos waste materials on municipal waste deposits in Norway. The investigations showed that not all waste facilities were handling such materials according to procedures described by the environmental authorities. It was also found that the statistical material indicated discrepancies with regard to the reporting of demolished asbestos wastes being delivered for depositing. The investigation was initiated by NORSAS AS.

80 Institutt for geologi og bergteknikk Hovedoppgaver 1999

Aas, Fredrik Eide (K. Sandvik)

Mekanisk-biologisk behandling av restavfall - teoretiske prinsipper og praktiske forsøk. Mechanical and biological treatment of solid waste - theoretical principles and practical experiments. There has been a long time co-operation on student exchange between RWTH and NTNU on student exchange. In the field of mineral processing the exchange has unfortunately been only one way, but it is highly appreciated from our side as the students get an invaluable experience working in a different environment. The subject of the thesis will be whatever is under investigation in Aachen, where a suitable junior supervisor has an interest in the project. In this case products from a mechanical- biological urban waste treatment plant was to be investigated. This was done by mineral processing as well as other physical methods. The purpose is to find treatment methods to minimise the amount of material to be put on waste dumps.

81 Institutt for geologi og bergteknikk Hovedoppgaver 1998

1998

Abd-Alla, Bakheet A. (S.O. Johnsen, M.Sc)

Correlation of the Upper Cretaceous Bentiu Formation in Heglig, Toma South and El-Nar Fields based on well logs, Muglad Basin, Sudan. This study aimed at correlating Upper Cretaceous Bentiu Formation reservoir in Heglig, Toma South and El-Nar Fields. Well logs from three fields are used in the interpretation. The result of this interpretation is used as a database. Formation boundaries, thickness and lithology were identified. Log fata are used for the detrmination of the porosity and the percentage of the shale dispersewd in the reservoir sands. The sedimentological cross-section of Bentiu Unit 1 helps in viewing the stratigraphic sequence and in determining the depositional environment. The wide laterally distributed Bentiu Formation sandstones indicate a large braidplane during middle and late Cretaceous. The major faults controlling thickness and depth of the formation reflect that the area had been tectonically active at the time of deposition. Most of the deposits are channel deposits with some bar deposits encountered at the well Toma South # 6. Porosity values vary widely even within small vertical sections. This phenomenon strongly indicates the dependence of porosity on clay mineral percentage, carbonate cements and the diagenetic constituents rather than depth of burial. Bentiu Formation thickness and depth increases gradually from Heglig Field (more closer to Muglad Basin eastern margin and away from the major faults down thrown) towards Toma South/El-Nar Fields (more closer to the basin axis and towards the direction of the major controlling faults down thrown).

Anfinsen, Ingvild (Kai Nielsen / Statoil)

Krafttilførsel i et livsløpsperspektiv. Supply of energy in a life cycle perspective. The work is an attempt to use LCA to evaluate the environmental effects and impacts of power generation, and try to express these effects by a single unit. Four cases were analysed, hydropower, wind, natural gas and bio-mass. The second part of the thesis used the same tool to try and evaluate the effects of future scenarios for energy consumption in Norway, based on the public investigation report “Balancing energy consumption and power generation in Norway towards 2020. (NOU 1998:11) The EPS (Environmental Priority Strategies) was found to be useful in making the analysis. The work was done in co-operation with the Statoil Research Centre in Trondheim

Barthkur, Devajyoti (A. Myrvang / NORAD)

An evaluation of the TBM performance in the highly jointed anisotropic rocks of the Himalayas Design of underground excavation under the difficult rock conditions of the Himalayas must rely more heavily on a “Deign as you go” –strategy than on traditional “design in advance” approach used in this areas in connection with TBM- projects.. The essential function of rock support is to maintain the equilibrium of the rock mass.

Belgum, Mari (K. Rokoengen)

Kvartærgeologisk utvikling i Oseberg-området. Quaternary development in the Oseberg area. The purpose of the thesis is to illustrate the Quaternary development in the Oseberg area, during and after the last ice age. Previous work, geotechnical reports and seismic interpretations are used in this report to confirm the Quaternary development at the north-eastern part of the North Sea Plateau. Five locations are chosen, with geotechnical borings from 100-150 m depth, and about 187 km of seismic profiles are interpreted to connect these locations. The Quaternary sediments constitutes approximately 200 m in the investigated area. The seismic profiles show a north eastern development, and a relatively parallel layering in the north-south direction. During Weichsel there was several iceadvances. At least two interstadials are probable during this period; around 30.000 yBP and 19.000 yBP. The last deglaciation of the shelf started around 15.000 yBP. The sedimentation in the Holocene period is almost insignificant. In this thesis new information is connected to previous work, but the material has been very extensive. Some more investigations is therefore recommended, to get a more secure interpretation of the Quaternary development in the Oseberg area.

82 Institutt for geologi og bergteknikk Hovedoppgaver 1998

Berg, Frode Krogh (S.O. Johnsen)

Bruk av diskriminantanalyse i karakterisering og prediksjon av heterolitiske avsetninger i den nedre jurassiske Tiljeformasjonen utenfor midt Norge. Application of discriminant analysis in characterisation and prediction of heterolithic deposits in the Lower Jurassic Tilje formation. Application of discriminant analysis in characterisation and prediction of heterolithic deposits in the Lower Jurassic Tilje Fm., offshore mid-Norway The lithofacies (core descriptions) that have been analysed in this study range from marginal marine and intertidal flats to shallow-marine deposits. The various lithofacies types are analysed in terms of response to the gamma ray-, neutron-, density-, acoustic-, and mocro-resistivity logs. Univariate analysis indicated a high degree of overlap in petrophysical responses from some of the lithofacies. This was supported by multivariate analysis. Principal component analysis (PCA) showed that the clustering of the lithofacies was better defined for individual logs. Discriminant analysis was used to create a profacies (probabilty facies) database. A profacies is expressed in terms of fractions, or probabilities, of the original lithofacies. The term is introduced in this study to avoid confusion with the term electrofacies as defined by Serra and Abbot (1980). The profacies, which are derived from lithofacies log responses, can not be regarded as true electrofacies. Consequently, a profacies serves as an intermediate term between lithofacies and electrofacies. The main application of the profacies database developed in this study is to predict profacies in non-cored wells. Combined with geological knowledge of the spatial relations of the lithofacies, the database may be a useful tool in the recognition and prediction of tidal deposits. The most critical uncertainties associated with the profacies predictions are related to coreshifts, fluid saturations, heavy minerals, data quality and non-uniqueness of well log responses.

Berger, Sean Peter (T. Malvik / Elkem)

Characterization of chromite ore quality. Kap. Erzincan area, eastern Turkey. Four chromite deposits from Turkey were investigated. The thesis has been carried out in co-operation with Elkem Rana and has included field work, as well as mineralogical, textural and mineral chemistry investigations and laboratory mineral separation test work. The ores consist mainly of chromite and serpentine. Some magnetite occurs as rims on chromite grains in host rocks and as fine grained particles or aggregates in the serpentine matrix, both in host rock and in the chromites. The deposits in general are banded with thickness of the bands ranging from centimetres to metre scale. The thickest bands seem to be located at the centre of the deposits and are of higher grade. The texture is quite similar for all the deposits with subhedral to anhedral chromite grains in the ores and subhedral to euhedral grains in the host rock. Grain size is ranging from 0,5 to 3,0 mm. Fractures and aggregate textures are common. Pull apart texture is observed in all deposits.

Bergh-Christensen, Rolf (B. Nilsen / E. Broch)

Grunnfrysing som tettende og stabiliserende metode. Ground freezing in the Oslofjord tunnel. At an early stage of the excavation of the Oslofjord subsea tunnel probe drilling ahead of the tunnel face indicated a serious weakness zone. A by-pass tunnel was constructed, and it was decided that the zone should be stabilised by ground freezing technique. The thesis gives an introduction to this method based on literature studies. The geological structure of the weakness zone is described as well as the executed and planned works for the freezing process.

Braathen, Øystein (S.O. Johnsen)

Strukturell rekonstruksjon av et geologisk profil, offshore Øst Grønland. Structural reconstruction of a geological profile, offshore East Greenland. A regional E-W striking seismic line offshore East Greenland has been interpreted based on structural geological and seismic stratigraphic principles. The cross-section have been divided into 13 units (A-M). A chronostratigraphic chart has been constructed, but as there are no wells available in the area real ages has not been indicated. It is however, supposed that the base of unit F is of Paleocene age and the top of unit I is of Oligocene age. In addition it is supposed that the base of unit D might be a base Cretaceous reflector.

83 Institutt for geologi og bergteknikk Hovedoppgaver 1998

12 time steps are reconstructed. Up to Paleocene, indications of an old rift-phase are found. The main rifting took place in Paleocene. It caused uplift and erosion of the hanging wall and deposition of a syn-rift unit E. In post Paleocene there were two compressional tectonic phases causing uplift and erosion of the foot-wall. Later, the whole succession was tilted clockwise due to an increase in sedimentation into the basin, most likely caused by glacial erosion.

Bugge, Jannecke (K. Rokoengen)

Vurdering av metoder for bekjempelse av oljesøl i strandkanten. Evaluation actions for combatting oil pollution in shoreline areas. The thesis gives a background for oil pollution and describes a range of beach processes and types. The properties of different oil types and spreading and disintegration are discussed. The methods for combatting oil pollution in the shoreline area are evaluated, including natural processes, physical removing, chemical, biological and other methods.

Bysheim, Njål (B. Nilsen)

Ingeniørgeologisk og anleggsteknisk analyse. Kimti II, Nepal. Engineering geological and construction engineering analysis. Based on study of available background material, field mapping and laboratory testing, a feasibilty study of the proposed Khimti II Hydropower Project in Nepal has been carried out. The Khimti II project includes underground powerhouse cavern and 5 km of tunnels. Planned installation is 27.2 MW. Main emphasis has been on evaluating planned design, stability and rock support requirement of the planned underground excavations. The estimated rock support requirement is relatively high, reflecting rather difficult rock conditions. Alternative, apparently more favourable tunnel allignments are also discussed.

Christensen, Jan Ari (K.L. Sandvik)

Materialflyt, resirkulering og økologisk effektivitet for aluminium i Norge. Material flow, recycling and ecological efficiency of aluminium in Norway. This is a survey of aluminium use and recirculation in Norway. The eccological efficiency appears to be quite high in parts of the industrial sector, while the recirculation in the consumer part of the market is quite low. Data were in many cases hard to obtain, and lack of reliable data is one bottleneck in the work to remediate this situation.

Dahl, Liv Marit (B. Brattli)

Forurensing i marine sedimenter. Contamination in marin sediments. Through many years different kind of waste, both industrial and municipal waste, have been released into the sea. Many places the naturally occurring ecosystem can not handle the huge amounts, resulting in seriously contaminated marine sediments. Different contaminants can accumulate in different kinds of organisms, and represents a threat to the ecosystem. Polyaromatic hydrocarbon (PAH) is an important group of contaminants. Degradation of these compounds in marine sediments is limited due to low availability of oxygen. This task is a laboratory study of both biotic and abiotic processes in marine sediments. Sediments were contaminated with the two important PAH-components naphthalene and phenanthrene. By simulating sea bottom, the degradation of these two compounds was studied. Effects of various parameters like grain size, amount of contaminants, currents and isolation from the water were examined. Another set of experiments analysed the potential for degradation of PAH by suspending and stir sediments to avoid anaerobic conditions. Fertilizers like nitrogen and phosphor were added to enhance the degradation. Different extractionmethods were examinated, and a simple and reliable method was developed. The grainsize of the sediments was found to be an important parameter. Degradation of PAH is slower in fine grain silt. Covering sediments with clean sediments does not effect the degradation. When sediment is totally isolated from the watercolumn by clean sediments on a synthetic filter there is almost no degradation. When easily degradable compounds are added, more heavily degradable compounds are degraded. By adding oxygen at a higher rate the degradation is enhanced. Addition of nitrogen and phosphor enhance it even more. By measuring the redoxpotential it is found that oxygen migrate from the water to coarse grained sediments.

84 Institutt for geologi og bergteknikk Hovedoppgaver 1998

Danielsen, Monica Christin (T. Myran)

Maksimalt arbeidsmiljø og minimal eksplosjonsrisiko - et dilemma? Maximum working environment and minimum explosion risk – a dilemma?

Dregelid, Kristine (K. Nielsen)

Utprøving av oljevernberedskapsplan for Nornefeltet ved bruk av Oscar. Testing of contingency plan for the Norne field by using Oscar. The candidate has used a 3-D simulation model, OSCAR, to investigate the best strategies for oil spill containment using different configurations of spill collecting equipment. The simulations looked at four situations with different wind scenarios. The OSCAR model has been developed by Sintef Dept. of Chemistry, and the thesis work was done as part of their evaluation of the tool. The Norne off-shore field was used as a test case for the study.

Fløttum, Linda (Kai Nielsen)

Miljøvaredeklarasjon for norsk naturgass. Environmental Declaration for Norwegian Gas. The objective was to develop a framework model for an environmental declaration of natural gas from the Norwegian shelf. The model was to be based on common LCA methodology. Environmental declaration of a product contains only objective information about the product and its environmental impacts, and shall not attempt to make any comparisons with similar products. The work was done for the Statoil Research Centre in Trondheim.

Fossli, Vidar (R. Sinding-Larsen)

Erfaringsbearbeiding av letemodellresultater fra prospektering før og etter boring med forslag om forbedrete prosedyrer for angivelse av ressurs- og sannsynlighets-parameteranslag. Learning about exploration plays using pre- and post-drill data for resource- and probability parameters, suggestions for an improved exploration process.

Frosthammer, Lene (K.L. Sandvik)

Tap og fortjeneste ved Empress Nickel Refinery, Zimbabwe. Loss and gain at the Empress Nickel Refinery, Zimbabwe. This thesis is carried out on basis of field work in Zimbabwe. Much of the work consisted of mapping the pollution around the refinery, which was considerable and also to look at possible revenues from a rehabilitation. Work was also done to establish the loss in money caused by todays discharges.

Goutam, Sagar Raj (B. Nilsen / NORAD)

Evaluation of pressure tunnel system, Khimti Khola Hydropower Project II, Nepal For the planned Khimti Khola hydropower project in Nepal, various designs of the pressure tunnel system, with and without shaft, have been proposed. This thesis is discussing the alternative designs based on evaluation of the engineering geological conditions, excavation aspects, stability/rock support and operation of the unlined waterways. A simulation model (FLAC-3D) is used to simulate the topography and calculate the minimum principle stress at the critical points of the tunnels. Based on this, the originally planned power house cavern is recommended to be relocated, and two new tunnel alignments are proposed.

Gunathilake, Gamlath (E. Broch / NORAD)

Review of tender design for Kukule Ganga Hydropower Project and modelling of the underground Power house.

Kukule Ganga Hydropower Project in Sri Lanka is planned with 70 MW installed capacity. The project area consists of Precambrian gneissic rock varieties of good quality. Topographical and geological condition of the area is well suited for an underground powerstation. A study of the shape, stability, need for support and the deformations of the power cavern has been carried out using the Universal Distinct Element Method (UDEC). The following conclusions were reached after this study: Cavern span can be reduced further by 3 m. The displacements at walls are much higher than in the crown. Grouted rock bolts and fibre reinforced shotcrete are used as rock support. The rock support reduces the displacement only marginally. Stress concentration arises in the roof and bottom of the cavern. Unlined waterway system is feasible for the project

85 Institutt for geologi og bergteknikk Hovedoppgaver 1998

James, Khalid Reuben (A. Myrvang / NORAD)

Hydrogeology of Pre-Cambrian rocks in the Kihansi area of the East Africa Rift Valley system, and associated leakage problems. The Lower Kihansi Hydropower projeect, Tanzania is used as a case history in connection with leakage studies. Unlined pressure tunnels with 870 m head is used in this project. A general study is made using the SEEP /W finite element model. The area is dominated by E-W striking fractures, which also is the direction of quite high tectonic horizontal stresses. Potential leakage is likely to happen along those fractures. Measurements indicate that the normal stress to the fracture planes normally will exceed the water head, preventing hydraulic jacking and increased leakage. However, some “ Low stress pockets” may be present. Proper high pressure grouting is thought to prevent major leakages.

Hatløy, Magnhild S. (R. Sinding-Larsen)

Prediksjon av litologiske facies og petrofysiske parameterfordelinger til bruk i reservoarkarakterisering. Bayesiansk klassifisering av facies gitt empiriske bønnobservasjoner. Prediction of Lithofacies and Distributions of Petrophysic Parameters which further can be used in 3D-Reservoir Description. Bayesiansk Classification of facies given empirical Well Observations.

Haug, Jon Bjarne (R. Sinding-Larsen)

Tredimensjonal sedimentologisk modellering av en stratigrafisk reservoarenhet innen Frøyfeltet. The 3D sedimentological modelling of the Frøy field exemplified through one stratigraphical reservoir unit.

Haugland, Kjell Øivind (A. Myrvang)

Vannproblematikk i forbindelse med fremtidig drift i Svea Nord. Evaluation of possible water inflow in the future Svea Nord Coal Mine. (Also presented at Ståle Tøften) The Svea Nord coal mine, Spitsbergen is developed almost entirely under varying thickness of glaciers, and with varying rock cover. The extent of permafrost under the glaciers may have crucial importance when considering possible water inbreak in connection with longwall mining with overburden caving. Based on field measurements and numerical modelling a model for permafrost depth in different parts of the future mine has been proposed. The model seems to coincide well with previous experience from water inbreak in the Gruve 7 mine in the same region.

Haugstøyl, Mona (K. Nielsen)

Arbeidsmiljø- og sikkerhetseffekter ved innføring av semiautomatisk rørhåndteringsutstyr offshore. Working environment and Safety effects when applying semi automatic pipehandling offshore. work was done for Phillips Petroleum Company, investigating how the introduction of mechanised drill pipe handling equipment has changed the occupational health and safety situation for the workers on off-shore platforms. Improvement were found in certain areas, but the new equipment also introduced some new health and safety problems, some of which were related to training of workers to operate the new equipment.

Hermanstad, Elin (B. Nilsen / Statkraft)

Khimti vannkraftanlegg, Nepal - Analyse av ingeniørgeologi, drivemetoder og bergsikring. Khimti Hydropower Project, Nepal - Analysis of Engineering Geology, Tunnelling Methods and Rock Support. (Joint diploma with Hovelsen) The diploma represents a follow up of an earlier project in engineering geology with purpose to make a first evaluation of the rock engineering conditions of the Khimti Hydropower Project in Nepal. As basis for the diploma, comprehensive field and tunnel mapping were carried out during the summer months and at the initial stage of the diploma work. The project has an underground powerhouse cavern and about 10 km of tunnels. It is planned to be opened in 2000, with a total output of 60 MW. Very difficult ground conditions have been encountered during tunnelling. Based on the mapping results, rock support and excavation methods at the hydropower tunnels, and the extent of rock support, have been analyzed. Among key issues have been integration of rock support with tunnel excavation and optimisation of methods according to local conditions.

86 Institutt for geologi og bergteknikk Hovedoppgaver 1998

Hovelsen, Morten (B. Nilsen / Statkraft)

Khimti vannkraftanlegg, Nepal - analyse av ingeniørgeologi, drivemetoder og bergsikring. Analysis of Engineering Geology. Tunnelling methods and rock support. Khimti Hydropower Project, Nepal. (Joint diploma with Hermandstad) The diploma represents a follow up of an earlier project in engineering geology with purpose to make a first evaluation of the rock engineering conditions of the Khimti Hydropower Project in Nepal. As basis for the diploma, comprehensive field and tunnel mapping were carried out during the summer months and at the initial stage of the diploma work. The project has an underground powerhouse cavern and about 10 km of tunnels. It is planned to be opened in 2000, with a total output of 60 MW. Very difficult ground conditions have been encountered during tunnelling. Based on the mapping results, rock support and excavation methods at the hydropower tunnels, and the extent of rock support, have been analyzed. Among key issues have been integration of rock support with tunnel excavation and optimisation of methods according to local conditions.

Hjørnevik, Jon Olav (K.L. Sandvik)

Gravitativ gjenvinning av metall fra FeCr-slagg. Gravity concentration of metal from FeCr-slag. Today metal is recovered from the FeCr-slag by magnetidc methods. This gives a poor concentrate which has to be remelted and a poor recovery. The aim of the present testwork in laboratory scale was to obtain a saleable concentrat as well as a secondary concentrate for remelting by jigging and other methods. This was shown to be possible.

Holthe, Kristin (K. Nielsen)

Total miljøanalyse av behandlingsmetoder for boreavfallet fra Snøhvit og Askeladden. Total environmental evaluation of treatment methods for drilling waste from Snøhvit and Askeladd. In connection with development drilling of the Snøhvit and Askeladden fields, both oil and water based mud will be used. The object of the thesis work was to make an environmental impact assessment of different ways to handle used mud after drilling. The analysis demonstrated that re-injection was the best way, both with regard to environmental impacts and costs. The other alternative would be to return the spent mud to a land based treatment facility. The work was done for the Statoil Research Centre in Trondheim.

Johannesen, Ulf Chr. (K. Sundblad)

En geologisk og mineralogisk undersøkelse av kvartsittforekomsten på Tananeset, Finnmark. A geological and mineralogical investigation of the Quartzite deposit on Tananeset, Finnmark, Norway. I denne diplomoppgave har en geologisk og mineralogisk undersøkelse av kvartsittforekomsten på Tananesset i Finnmark blitt gjennomført. Feltundersøkelsen er basert på geologisk (litologisk, mineralogisk og strukturell) kartlegging av 1,5 km2 stort område i målestokk 1:1000 samt i borkjerneprøver. Laboratorieundersøkelsene innbefatter geokjemisk og petrologisk (mikroskopi) karakteristikk av kvartsitten i den hensikt å kvalitetsbestemme og kvantifisere brytverdige ressurser av kvartsitt. Resultatet er levert i form av tre forskjellige malmberegningsalternativ.

Kalskin, Randi (B. Brattli)

Kartlegging av potensialet for grunnvarmeuttak fra løsmasser i Elverum. Mapping of the potential for Ground Source Heat from Glacial deposits in Elverum. Oppgaven inngår i NGUs prosjekt: Kartlegging av grunnvarmepotensialet i Elverum. Formålet er å lage et temakart som viser potensialet for grunnvarmeuttak fra grunnvann i løsmasser. Kartleggingen skal bygge på eksisterende data i form av kvartærgeologiske og hydrogeologiske kart, tidligere undersøkelser av løsmasser og grunnvann og relevante data fra målinger, undersøkelsesboringer og målinger av grunnvannstemperatur.

Kamsvåg, Rannveig P. (T. Malvik)

Ressursgrunnlaget for produksjon av høyren kvarts i Hamarøy-Tysfjord området. Resources for the production of high quality quartz in the Hamarøy, Tysfjord region. The thesis has been carried out in co-operation with Norwegian Crystallites. Quartz from different pegmatites in the region was sampled and investigated in the microscope and with SEM. The objective was to obtain data about the quality of the pegmatites and the possible use of the quartz as a raw material for high quality products.

87 Institutt for geologi og bergteknikk Hovedoppgaver 1998

Klungland, Øystein (E. Broch)

Nytt konsept for lagring av LNG i berghaller. A new concept for storage of LNG in rock caverns. A storage concept based on large cylindrical rock caverns lined with reinforced concrete and insulated with a layer of foamglass is described. The opening between the rock and the insulating material is filled with clay. Different clay materials have been tested in the laboratory to study their behaviour at low temperatures. Mathematical modelling has been done to study the temperature gradients from the Liquified Natural Gas to the rock. A cost estimate is presented.

Lambileki, Peter A.H. (E. Broch / NORAD)

Khimti I Hydropower Project – tunnel support systems – anticipation and reality. The thesis describes the factors and the process that may influence on the decision making on rock support alternatives for hydropower tunnelling contracts in Norway and Tanzania, particularly at the Pangani Falls and the Lower Kihansi hydropower projects. Also the influence on the involved parties is discussed. Predicted geology has been correlated with encountered geology for the two Tanzanian projects.

Mathisen, Ingvild Gisken (K. Nielsen)

Miljøvaredeklarasjon for norsk naturgass. Environmental declaration for Norwegian Gas. The objective was to develop a framework model for an environmental declaration of natural gas from the Norwegian shelf. The model was to be based on common LCA methodology. Environmental declaration of a product contains only objective information about the product and its environmental impacts, and shall not attempt to make any comparisons with similar products. The work was done for the Statoil Research Centre in Trondheim.

Mathiesen, Thomas Korssjøen (A. Myrvang):

Kohala Hydroelectric Project – Stabilitet og bergsikring i kraftstasjonen. Kohala Hydroelectric Project - Stability and rock support of the power station complex. The geology of the area is comlex. The rocks in the powerhouse consists mainly of sandstones and shales. Part of the work is the use of finite element modelling ( Phas 2 software) to model the rock support. The conlusion is that the software is completely unsuitable for practical support design, but may give some indications of where special support requirements are neccessary.

Md. Abdus Salam Khan (S. Lippard / Norad M.Sc.)

Sequence stratigraphy of the Stord basin, northern North Sea Ten sequences are recognised in the Upper Jurassic to Quaternary sediments where sequences 1 and 2 are mostly shales that were deposited under regressive shallow marine low energy environments in the late Jurassic. Four parasequences are distinguished within sequence 1. Sequence 3 is equivalent to the Lower Cretaceous Cromer Knoll Group composed of dark claystones and marls that were deposited in shallow marine environments. Sequence 4 is equivalent to the Upper Cretaceous Shetland Group composed of chalk and deposited in open marine conditions. Sequences 3 and 4 are both transgressive. Sequence 5 is mainly composed of mudstones, but in the eastern part of the basin it is more sandy. It was deposited in the early Paleocene to early Eocene in transgressional to regressional environments. Sequence 6 of middle to late Eocene age, is composed of mudstones with a high input of terrigeneous clastics in the east. The sequence is highly deformed (overpressured clays) and shows chaotic reflections. The depositional environments were marine transgressive to regressive. Sequence 7 is of late Oligocene age and composed of mudstones. Deposition took place in transgressive to regressive environments. Sequences 8 and 9 are composed of progradational packages of middle-late Miocene and Pliocene age respectively and the depositional environment was marginal to shallow marine. Sequence 10 is composed of Quaternary glacial deposits that consist of clays, unconsolidated sands and gravels.

88 Institutt for geologi og bergteknikk Hovedoppgaver 1998

Mikkelsen, Tove Bergkvam (S.O. Johnsen)

En sekvensstratigrafisk tilnærming for å forutsi fordelingen av sandstein innen Brent gruppen, nordlige del av Nordsjøen. A sequence stratigraphic approach to sandstone prediction within the Brent Group, Northern North Sea. A series of sequence stratigraphic and lithostratigraphic maps have been constructed in order to determine where the Brent Delta shales out to the north in the northern parts of the North Sea. The sequence stratigraphic mapping process was performed in more detail, and porosity data in the form of CPI curves was used. Structure, average porosity, net/gross and net sand were mapped for 19 systems tracts that corresponds roughly to the Brent Group. Depth/porosity plots were in addition constructed for the approximately 50 wells that were considered in the sequence stratigraphic approach. According to the lithostratigraphic approach, thickness and net/gross were mapped for the 6 formations: Oseberg, Broom, Rannoch, Etive, Ness, and Trabert. An arbitrary 3-D seismic line was also included in the study to try to confirm where the Brent Group shales out. The sequence stratigraphic, and the lithostratigraphic series of maps both show that the Brent Group starts to shale out at roughly 61°30‟N. This is confirmed by the 3-D seismic line. The shaly parts of the Brent Group extend further to the north. Implications for prospectivity are, based on this, recomended to be concentrated south of 61°30‟N.

Moen, Kari (T. Malvik)

En kartlegging av relasjoner mellom råstoffkvalitet og produktkvalitet for karboner ved produksjon av høyverdig kalkbasert fyllstoff og bestrykningsmiddel. Relations between raw material and product quality for carbonates used in filler/coating industry. Carbonates samples from the Viin order to define and to quantify relations between in situ quality of the carbonate deposit and product quality. The investigation shows that the occurrence and texture of the grapithe in the carbonate is the most crucial factor regarding the product quality of ground and micronized products.

Ness, Liv Marte (B. Brattli)

Miljøteknisk grunnundersøkelse av Sollerudstranda. Environmental Site Investigation of Sollerudstranda.

Nikolaisen, Trine Solvang (K. Nielsen)

Interaksjoner mellom olje og sediment. Oil and Sediment Interactions. Improved understanding of the interaction between stranded oil and shoreline sediments will ease the planning of shoreline treatment in case of oil spills. The candidate performed model tests in the laboratory in order to investigate how different properties of crude oil and bunker oil will influence penetration and retention in a sediment column. The work was done for Sintef Dept. of Chemistry.

Nordahl, Kjetil (S.O. Johnsen)

Regional sammenligning av avsetningsmønstre og provenanse for Broom- og Oseberg-formasjonene (se aalen) i nordlige Nordsjøen. A regional comparison of the depositional patterns and provenance for the Broom- and Oseberg-Formations (late Aalenian) in the northern North Sea. Sedimentological, mineralogical, and log data have been used in order to compare depositional patterns and provenance significant charactristics for the Broom- and Oseberg- Formations in the northern parts of the North Sea. A depositional model based on cross-sections, classification diagrams and quantification of facies distribution, based on the GR-log in non-cored wells and intervals has been estabilshed. Cores from seven wells have been redescribed. Together with earlier described cores this is the basis for the cross- sections. 29 thin sections have been point-countered for primary mineralogy, diagenetic products and differnt forms of porosity. An estimate of the primary mineralogy in the sediments based on diagenetic connections gives provenance significant characteristics. By calculating the shale volume from the GR-log and realating this to the characteristic

89 Institutt for geologi og bergteknikk Hovedoppgaver 1998 claycontent in the differnt facies, a facies distribution has been estimated. The criteria for the facies distribution is calibrated against the cored wells 30/6-5 and 30/6-7. The Broom- and Oseberg- Formations respectively, was deposited transversly into their basins. They both show a marked increase in thickness across structural lineaments of permo-triassic age and wedges out aginst the grabenaxis. The Oseberg Formation is deposited in two outbuilding pulses which are characterised by different progardational directions. The initiation of the Oseberg Formation was a result of blockrotation of permo-triassic faults, and an uplift of the Horda Platform which was exposed to erosion. The platform developed into a braided riversystem. West of a line indicating the maximum flodding surface for the Osebergsystem (represented by the Rannoch shale) the formation is deposited in a shallow marine, fandelta system. The Broom Formation has been interpreted to be deposited by similar processes in a similar environment. No indications of fluvial sediments have been found, but a fluvial system is nevertheless supposed to be responsible for bringing the sediments from the East Shetland Platform into the basin. Local structural highs may have acted as source areas for the Broom Formation. The Oseberg Formation shows larger variations in facies than what can be seen in the Broom Formation. From the mineralogical study, the K-feldspar content indicates that the two lobes constituting the Oseberg Formation have different provenance. The K-feldspar content in the Broom Formation shows similarities to the youngest outbuilding phase in the Oseberg area.

Otterness, Per Ole (E. Broch)

Numeriske undersøkelser av bergmekaniske forhold ved en gasslagringskaverne i salt. Numerical studies of the rock mechanical behaviour of a gas storage cavern subjected to different thickness of rock salt layers and variable in situ rock stresses. The numerical analysis was carried out using The Finite Element Code ANSYS 5.0. A cavern with a volume of 2 mill. m3 was modelled, and the development of the stress situation over a period of one year was analysed.

Panthi, Krishna K. (B. Nilsen / NORAD)

Direct link between Hetauda and Kathmandu - Evaluation of proposed road tunnels, Nepal The proposed road link between Hetauda and Kathmandu in Nepal includes several long tunnels. Pre-feasibility study of the project was carried out in 1993. This thesis evaluates the engineering geological conditions of the proposed tunnels, analyses the geotechnical complexity and risk, and contains preliminary time and cost estimates. The project area is located in the lesser Himalayan crystalline rocks, typically represented by quartzite, marble, mica schist and limestone. All three of the proposed alignment alternatives are found to be technically feasible, with alternative 1 as the best. Conventional drill and blast tunnelling is recommended for excavation. Further engineering geological investigations are recommended.

Peikli, Vegard (T. Myran)

Kartlegging av arbeidsmiljø og ytre miljø ved A/S Olivin. Investigation of labour and external environment at A/S Olivin.

Rasch, Maria (S.O. Johnsen / IKU)

Diagenese av dypt begravde sandsteiner fra Norskehavet med vekt på effekt av poreveggsmineralogi på reservoaregenskapene. Diagenesis of deeply buried sandstones from the Norwegian Sea with emphasis on the effect of porelining mineralogy on the reservoir properties. Deeply buried sandstones on Haltenbanken have been investigated with respect to porelining chlorite. Because porelining chlorite hampers quartz overgrowth, it is a positive contribution to the preservation of porosity. A high content of porelining chlorite can be related to near coast, tidally dominated depositional environments influenced by riverwater. Where riverwater flows into the sea, ironrich clays will precipitate as a result of reaction between the clayparticles in the riverwater and the ions in the seawater. Among the investigated depositional environments, subtidal channel deposits had the highest content of porelining chlorites. Mineral chemical studies (SEM EDS), XRD analysis and SEM secondary electron analysis have been used in order to map in detail the chemical, mineralogical and morphological relationships of the clay material in the sandstones. The most important results from this studies are that the porelining chlorites constitutes two mineralchemical phases in the form of a core and a fibrious edge. The cores mostly consists of illite, but may also contain ironrich chlorite. The outer

90 Institutt for geologi og bergteknikk Hovedoppgaver 1998 fibrious edge contains only ironrich chlorite. Analysed ooids occurs with the same mineralchemical composition as the porelining chlorite. The chlorites are overall 7Å chlorites, and the fibrious morphology shows an authigenic origin.

Salthe, Hilde (B. Brattli)

Modellering av grunnvannsstrømming og advektiv forurensningstransport på Bardufoss Hovedflystasjon ved bruk av Visual MODFLOW. Modelling of groundwater flow and advedtive contaminant transport at Bardufoss Airport using Visual MODFLOW.

Scheldt, Therese (A. Myrvang)

Inngangsparametre til numerisk modellering innenfor bergmekanikken. Input parameters for numerical modelling in rock mechanics. A number of cases associated with a possible underground railway freight terminal is used as case. Important in-put parameters like in-situ rock stress and mechanical properties are varied for different geometries of the underground excavations, using the UDEC computer code. A major conclusion is that the in-situ stress is a paramount in-put parameter.

Seda, Vedastus Jerome (S. Lippard / NORAD)

Structural studies, Rukwa rift basin, southwestern Tanzania This study aims at acquiring more insights into the structural styles, geometry and tectonic evolution of the Rukwa rift basin, southwestern Tanzania along a part of the East African Rift System. The objectives have been achieved through structural seismic interpretation of data supplied by the Tanzania Petroleum Development Corporation (TPDC), supplemented by a review of the available literature on the basin from various sources.

Sedal, Helene (K. Sandvik)

Deponigassutnyttelse - samfunnsøkonomisk og miljømessig analyse. Landfill Gas Utilization – Socioeconomic and Environmental Analysis. Innlev. 1998 In all domestic waste dumps methane and carbon diaxide are formed. Both are considered greenhouse gasses but methane is the most serious. A survey of all plants collecting gass from dumps in Norway were carried through. Investment is in average 14 NOK per ton garbage dumped. Investment for energy recoverage was 3.7 NOK per annual kWh. An alternative to methane collection is oxidation to carbon dioxide in the topsoil. Technology for doing this is under developement. Field work was carried out at the Hegstadmoen fill site in Trondheim to evaluate the potential for gas collection.

Shubh, Pathak (B. Nilsen / NORAD)

Khimti Khola II Hydropower Project - Stability and support of tunnel portals For underground hydropower projects in steep topography, the stability of tunnel portal areas is of major concern. This thesis is evaluating the engineering geological conditions and analysing in detail the tunnel portal situation of the planned Khimti Khola II hydropower project in Nepal. Analyses based on stereographic projection techniques and limit equilibrium methods show that the portal slope of the access tunnel to the power house is stable, while for the adit portal slope supplementary rock support and drainage are recommended.

Slagstad, Trond (A. Krill)

Berggrunnsgeologi i Bymarka. High-K2O plagiogranite and greenstones in ophiolitic rocks of Bymarka, Trondheim Geochemical investigations, as well as regional geological considerations, suggest that the Bymarka greenstones, consisting largely of pillow lavas and sheeted dikes, formed in a mid-ocean ridge setting, possibly a marginal basin. Gneissic trondhjemites, occurring as one large coarse-grained body and several thin (10‟s of m), fine- to medium-grained dikes, have a geochemical signature suggesting that they are plagiogranites. The geochemical results indicate that secondary processes, most likely sub-seafloor metamorphism, are important in the formation of plagiogranites, as has been suggested by other authors.

91 Institutt for geologi og bergteknikk Hovedoppgaver 1998

Stavik, Gaute (S. Lippard)

Påvirkningen av støy for strukturell tolkning av attributtkart på Njordfeltet. The Influence of Noise in the structural interpretation of attribute maps on the Njord Field. Seismic attribute maps have in several reports provided a useful tool in predicting faults, particularly those close to or below seismic resolution. These tools have now been tested on three horizons on the Njord Field. The resulting attribute maps contain abundant noise, and detailed structural interpretation has been difficult to accomplish. Different attempts to improve both the seismic interpretation and the attribute maps have been done. From this is has been concluded that the attribute maps are more or less independent of the seismic interpretation. Of more importance is the quality of the seismic data. If this is poor, which is the case for parts of the Njord Field, generation of noise is expected. Applying filters to the attribute maps have shown to be of great value for the timedip and relief maps, while the azimuth maps do not display similar improvements. After filtering, the maps are possible to use for structural interpretation. However, fault population analysis from the timedip map has indicated an effective resolution of 15 ms. This is much higher than earlier analysis from seismic interpretation. For this reason it is not been possible to detect any faults not visual on the seismic data. The fault population analysis has also demonstrated that some sub-populations display more than one power-law. Predicting faults below seismic resolution from a general power-law may hence result in wrong estimates.

Stenbakken, Idun E. (K.L. Sandvik / Idrefjell Fjellanlegg)

Miljøledelse i reiselivsnæringen ISO 14001 - Environmental control at Idrefjell Fjellanlegg. Environmental management in the tourist business. The student has here carried out the work neccecary to certify a Swedish mountain resort according to IOSO 14001 the environmental standard. The thesis describes all environmetal hazards applying to a winter and summer resort business in the mountains. Some are hard to quantify and even harder to do something with. Implementation requires a strong will to imprve the environmental standards by the employes as well as the guests.

Thomassen, Astri (K. Sandvik)

LCA metodikk benyttet i konseptfasen i prosjekter for utvikling av oljefelt. LCA-methodology applied in the conceptual phase of oil field development projects. The main objective of this study was to give an introduction to the LCA (life cycle analysis) methodology and available weighing tools and to describe thedifferent phases in an Oil Fiels Developement project. Further to perform an LCA on an actual project in the conseptual phase and thereafter to evaluate the outcome of the LCA and the suitability for performing LCS„s in the conceptual phase. The thesis is to be kept confidential.

Tøften, Ståle (A. Myrvang)

Vannproblematikk i forbindelse med fremtidig drift i Svea Nord. Evaluation of possible water inflow in the future Svea Nord Mine. (Also presented at Kjell Øivind Haugland) The Svea Nord coal mine, Spitsbergen is developed almost entirely under varying thickness of glaciers, and with varying rock cover. The extent of permafrost under the glaciers may have crucial importance when considering possible water inbreak in connection with longwall mining with overburden caving. Based on field measurements and numerical modelling a model for permafrost depth in different parts of the future mine has been proposed. The model seems to coincide well with previous experience from water inbreak in the Gruve 7 mine in the same region.

Taaje, Kjetil (S. Lippard)

Vurdering av prospektiviteten i 15. rundeblokker før og etter testing. Er prospektiviteten blitt bedret eller svekket i Norskehavet som resultat av 15. runde? Evaluation of the prospectivity in 15th. Round blocks before and after drilling. Has the prospectivity become more or less favourable in the Norwegian Sea as a result of the 15th Round? Allocation of blocks in the 15th Round took place 22nd January 1996. Of the 18 licences, 14 are located in the Norwegian Sea, many in new deep water areas of the Møre and Vøring basins where seismic surveys had revealed large undrilled structures. These structures were expected to have Cretaceous and Tertiary plays as the main targets. The main risk was seen as the presence of an effective oil-prone source rock. Flat spots and seismic anomalies indicated the presence of hydrocarbons. So far (December 1998) 7 of the 14 licences have been drilled. 4 of the 7 have resulted in 3 gas

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(Ormen Lange North and South, and Nyk High) discoveries and one oil (Skarv) discovery. Nevertheless there is some disappointment that the largest discoveries were gas and that other large structures (Helland-Hansen, Vema) were dry. The results so far indicate the presence of good reservoirs at several stratigraphic levels, which was seen as a major risk factor before drilling. It is considered most likely for further discoveries of gas in the remaining licences to be drilled in the Vøring and Møre basins.

Ulleberg, Ola (K. Nielsen)

Økonomisk Optimalisering av finstoff ved pallsprengning. Economic Optimalisation of Fines Production in Quarry Blasting The work undertook an investigation of how to optimise blasting design with regard to the generation of fines in crushed aggregate production. The investigations were done during regular full scale production at the Steinskogen quarry of Franzefoss Bruk AS. Blast design parameters, mainly drilling patterns and powder factors, were changed in a systematic way, involving several blasts. The fines generation was monitored by using conveyor scales on the product conveyors after the first two crushing stages.

Ziping, Huang (B. Nilsen / NORAD)

Ertan hydroelectric Project - Analysis of rock slope stability For the Ertan hydroelectric project, presently under construction in Sichuan, P.R. China, rock slopes with heights in excess of 100 meters have been excavated. Difficult rock conditions have been encountered on several occasions, and considerable effort has been put on careful excavation and rock support. In this thesis the stability of the high rock slopes at Ertan is analysed with particular emphasis on the power intake and spillway intake slopes. Analyses based on UDEC distinct element and SARMA limit equilibrium analyses show that the slopes are satisfactory stable after excavation, provided that rock support and drainage are carried out.

Øiseth, Klaus Emil (K. Sandvik)

Nettbruk i oljelenser, og eksperimentell sammenlikning av lensemodeller med og uten stabiliseringsnett. Use of Net in Oil Booms, and Experimental comparison of Boom Models with and without Feather Net.. Attachment of a netting under booms to contain oil spill will interfere with the hydrodynamic conditions. Earlier work on oil slippage under booms is investigated in the literature. A test tank investigation was carried through to evaluate the opinions gained from the literature search. The thesis is kept confidential.

Aarrestad, Bjørn Andreas (B. Brattli)

Geokjemisk modellering med PHREEQC – muligheter og begrensninger. Geochemical modeling with PHREEQC – Capabilities and Limitations. Kandidaten skal gjennom et litteraturstudium og med egne eksempler vise muligheter og begrensninger vi har ved geokjemisk modellering med modelleringsprogrammet PHREEQC. I oppgaven skal programmet presenteres slik at det blir lettere tilgjengelig for våre studenter i undervisningssammenheng.

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1997

Abe, Reiko (E. Broch / NORAD)

Construction and Contract System for Underground Structures in Norway. One focusing point in this thesis is the importance of the procedures during construction. This is based on the author‟s practical experience from studies carried out at two Norwegian projects on underground structure: National Theater Station Project in Oslo and Fløyrli Hydropower Project near Stavanger. Another point is the comparison between Japanese and Norwegian systems, posing importance on the construction procedure. Particularly the possibility for application of Norwegian tunnelling methods in Japan is considered. In addition, the difference of consideration for safety is also described.

Amundsen, Veronica (R. Sinding-Larsen / Phillips)

Studie av forholdet mellom forkastninger, sprekker og permeabilitimålinger i Ekofiskfeltet. A study of the relationships between faults, fractures and permeability measurements in the Ekofisk Field.

Bang, Rune Eivind (E. Broch)

Maskinell rensk - erfaringer fra Fagernes vegtunnel. Mechanical scaling – experience from Fagernes road tunnel. Scaling is of vital importance for the safety of the tunnelers. Mechanical scaling is gradually replacing the more risky manual scaling. In the mica schist and mica gneiss rocks in the Fagernes tunnel a rotating drum with spikes have been tested. Positive results have been obtained such as improved tunnel environment, improved quality of the scaling and reduced time consumption. On the negative side is the fact that the tunnelers may loose contact with and thus the feeling for the quality of the rock.

Bentås, Dagfinn (A. Myrvang)

Evaluation of rock support in the Lærdal road tunnel. The 24.5 km Lærdal road tunnel experienced severe rock stress/spalling problems, particularly in the roof of the tunnel, due to high tectonic horizontal stress. This work reveals that there is a relationship between the rock types and the rock support required, in the sense that the rock stress intensity varies with stiffness / strength of the rock mass.

Berntzen, Trine (B. Brattli)

Kartlegging av arsen og sink i overflatejord i barnehager i Trondheim og vurdering av helserisikoen ved høye konsentrasjoner. A mapping of the arsenic- and zinc-consentrations in childrens outdoor areas in the city of Trondheim and an evaluation of the health risk connected to high consentrations. 152 soil samples from kinder gardens in Trondheim have been analysed with emphasis on arsenic and sink level. The analyses is related to the standard values given by SFT (Statens Forurensnings Tilsyn). 6 samples revealed too high concentration of arsenic, while 14 had too high concentration of sink. It is concluded that the sources for the “high” metal concentration is antropogenic. As children “eat” soil in the kinder garden, possible toxicological effects from these metals on small children has been evaluated. The conclusion is that arsenic at the actual concentration can cause sustemic effects inside the body, but it depends on what form the metal appears in the soils that the children “eat”. In this actual case the metal seems to appear in a form which is less available for uptake in the ingestion system.

Bhatti, Tariq Javed (B. Nilsen / NORAD / Norconsult)

Foundation stability analyses of intake dam, Neelum-Jhelum hydroelectric project, Pakistan. The engineering geological conditions of the planned intake dam at the Neelum-Jhelum hydroelectric project are analysed based on review of available background material. Foundation stability is analysed by stereographic analyses and limit equilibrium methods, and the foundation quality by bearing capacity analyses. It is concluded that except minor concern connected to differential settlement, there is no significant stability problem.

94 Institutt for geologi og bergteknikk Hovedoppgaver 1997

Bjordal, Heidi Kristin (A. Myrvang / Jernbaneverket)

Evaluering av ulike typer bergsikring i relasjon til ingeniørgeologiske forhold i deler av anlegget Nye Nationalteateret Stasjon. Evaluation of different rock support in relation to engineering geological conditions during constructions of parts of the new Nationaltheateret, at the new Nationalteateret underground railway station, Oslo. The underground railway station is siuated in folded Cambro-Silurian shales and limestones with Q-values in the range 0.001 – 2. The span of the cavern is 22 m with only 20 m rock overburden. A major part of the rock support consists of reinforced shotcrete ribs. Static calculations carried out in this work show sufficient safety factors. Convergence measurements in the cavern and stress measurements in ribs confirm this conclusion.

Bratli, Elisabeth (R. Sinding-Larsen)

IRAP RMS Modelling of the Ainsa Turbidites. This thesis har investigated the Ainsa turbidites in the South Central part of of the Pyrenees and more spesificly the challel lobe complex Ainsa II which can be separated into several sub-units. In block 15/5 on the Norwegian shelf a possible upper Heimdal submarine fan has been identified and this fan is compared with the Ainsa system in an attemt to establish a quantitative analogue. IRAP RMS has been used to model the grain size distribution within the Ainsa II turbidites. Conditional simulation with long anisotropic ranges gave the best results. Based on the results from well 15/5-5 a relation between grain size and permeability was established. The permeability values were thereafter used in modelling to investigate how this parameter behaved during upscaling. Grid with different sizes used in the upscaling showed that there was no significant difference between the permeability values in the x and y direction between the different grid sizes. Permeability in the z direction was however greatly reduced as a consequence of upscaling. An alternative model was established in order to compare the effect resulting from the sub-division of the system in channels as compared to the treatment of the different units as one system. The results indicate that for a system like the Ainsa turbidites a detailed geomodel is not necessary as long as the purpose of the modelling is upscaling and further reservoir simulasion.

Brovold, Janne Birgitte (Sveinung Løset)

Kartlegging av forurensing fra søppelfyllinga i Longyearbyen. Mapping of pollutant spreading from the garbage-dump at Longyearbyen.

Eidem, Truls M (K.L. Sandvik)

Application of Surfactant for cleaning Soil contaminated with Creosote. This was an investigation concerned with off-site soil remediation. The effectiveness of soil washing can be improved by the use of surfactants and a practical study was carried out to assess a number of surfactants.

Feragen, Helen (K. Rokoengen)

Yngre Dryas isfremstøt i Trondheimsfjordområdet. Younger dryas ice front advance in the Trondheimsfjord area. The deglaciation of the Trondheimsfjord area during the early Younger Dryas chronozone is inferred from former Quaternary geological research, glacier dynamics, geotechnical borings, seismic profiles in marine areas, field work and radiocarbon dates. The studies have concentrated on restricted areas: Agdenes/Ørland, Selnes and Rissa in the outermost Trondheimsfjord area, and Borgåsen, Leksvik, Malvik/Ranheim, Dragvoll/Moholt and Gløshaugen in the innermost Trondheimsfjord area. Ørland, submarine ridges across Stjørnfjorden and Trondheimsleia at Garten, and a distinct ridge between the lake Botnen and the fjord at Rissa, are assumed to represent ice - marginal deposits, caused by a glacier moving along the fjord before 11 800 B.P. During the Allerød chronozone (11 800 - 11 000 B.P) there was significant deposition of glaciomarine clays in an ice-free fjord, and different molluscs and whale species lived under arctic conditions. A marked ice front advance fjord took place after c. 10 900 B.P, and the glaciomarine clays were consolidated to form till. Deposits at Selnes, Borgåsen, and Dragvoll/Moholt are assumed to represent till formed by consolidation of glaciomarine clays by a glacier moving in from the fjord. Radiocarbon dates indicating a glacier advance to the outermost fjord area after c. 10 900 B.P are recorded at Rissa and Selnes. The results indicate a major glacier advance during the Younger Dryas chronozone, especially along the fjord.

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Areas covered by the advancing glacier and the duration of the advance are not specified. Further studies in complicated areas (Trondheim), and in areas not covered by this work are recommended.

Ferstad, Tone (S.O. Johnsen / Phillips)

Sekvensstratigrafisk analyse av paleocene sedimenter langs Møremarginen, 62N-64N. Sequence stratigraphic Analysis of Paleocene Sediments along the Møre Margin, 62N - 64N.

8 sequences have been mapped by the use of seismic- and well-data. The deposition of the Rogaland Group is mainly controlled by tectonics and paleotopography, with a less significant componenet of eustatic sea level control. Uplift of the eastern mainland resulted in a major shelf outbuilding along the margin in Paleocene time. These sediments were deposited above Cretaceous sedimenents deposited as passive basin infill in the Møre Basin. The uplift was associated with the development of a hot spot in the Greenland - Shetland area. The collapse of the hot spot in Late Paleocene/Early Eocene time related to the rifting in the NE Atlantic was responsible for a transgressive phase in the North Sea towards the end of Paleocene. However, on the Møre Margin the transgressive phase is overshadowed by local tectonics, including reactivation of older lineaments. This may indicate a more northern component of sediment supply. Mesozoic lows and transfer zones along the Møre-Trøndelag Fault Complex have most likely created depocentres for the sediments. Lowstand wedges, and possibly slope fans, constitute the main part of the Paleocene interval in the study area. Where sandstones in these units are encased in silts and clays, they may form stratigraphic traps. A combination of structural and stratigraphic processes may form trapping geometries.

Fossan, Ingar (B. Brattli / NGU)

Grunnvannsundersøkelser i fjell i Hjørungavåg, Hareid kommune. Groundwater investigations in hard rock, Hareid county. NGU was in 1997 engaged by Hareid municipality to investigate the groundwater resources in hard rock within the minicipality. This diploma is a part of that project, and is limited to the investigation of a certain hard rock aquifer at a place called Hjørungavåg. This aquifer is rather special compared to most hard rock aquifers in Norway. A/L Hjørungavåg vassverk is already producing water from the aquifer from three wells and underground springs. The three wells has an extraordinary high yield compared to the catchment which drains to the aquifer. The main goal of this diploma is to evaluate the geological reasons for this special high yields, and estimate the potential for further production of drinking water from the waterworks. In August 1997, NGU, Professor Bjørge Brattli from NTNU and the undersigned, carried out a five day long field work to investigate the hydrogeological properties of the aquifer. The survey included mapping of the local joint pattern, VLF, wateranalysis from the springs and wells together with short-time pumping tests of the wells at the waterworks. The two most actual methods for increasing the capacity of the waterworks is: 1) install more powerful pumps and 2) drill a new hole.

Gilje, Anne-Merete (E. Broch)

Cern-Prosjekt LHC. Large underground constructions at Point 5. The geological part first covers the history and development of the area, and then concludes with a closer description of the rockmass and its engineering properties. Also included in this section are the varying geotechnical parameters, and the technical aspects of the rockmass. The second part concerns the construction of the caverns. First the proposal given by CERN is described, and then two alternatives are given by the author. These descriptions take into consideration several aspects upon which a conclusion is drawn, as to which is the best excavation sequence. However, in this case, both the time and the cost for the proposals were basically equal, and further investigations will be made on the two proposals given by the author. This is done with the Finite Element Method and found in the main part of this project.

Glasø, Stephen B. (K.L. Sandvik)

Kartlegging av miljøskadelig avfall - En samfunnsøkonomisk vurdering av miljøkonsekvenser. A Survey of waste harmful to the environment - An economical assessment of consequences.. The city of Trondheim had a pilot project to evaluate selective collection of domestic waste. Some fractions were to be incinerated as before, some shold be recirculated and some carefully dumped. One fraction to be carefully dumped was

96 Institutt for geologi og bergteknikk Hovedoppgaver 1997 called environmetnaally sensitive waste. This material was analyzed to find how well it was separated from other waste fractions. Calculations were also carried out to evaluate the effect upon the discharge from the incineration plant.

Gunapala, Lakshitha (E. Broch / NORAD)

Evaluation and redesign of the tunnels and powerhouse cavern at the Kukule Ganga Hydropower Project based on Norwegian experiences. Kukule Ganga Hydropower Project in Sri Lanka is planned with 70 MW installed capacity. The project area consists of Precambrian gneissic rock varieties of good quality. Topographical and geological condition of the area is well suited for an underground powerstation. The following conclusions were reached after this study: (1). Tunnel system could be redesigned as unlined tunnels with supports only at places where they are necessary. (2). Moderate stress level and good quality rock at the power cavern location make it possible to design a cavern with vertical walls and flat arched roof. (3). Span of a cavern is the most critical dimension. Norwegian experience for compact cavern layout designs could be used to optimize cavern volume and thus to reduce the cavern span.

Hagen, Anette Wold (K. Rokoengen / Noteby A/S)

Injeksjonsarbeider i Romeriksporten. Grouting works in Romeriksporten. The tunnel Romeriksporten is a part of the high velocity railway system, which is being built in connection with the new Oslo airport at Gardermoen. The length of Romeriksporten is almost 14 km. The railway system Gardermobanen is supposed to be ready on the 8th of August 1998, when the airport will be opened. This report describes the grouting works in Romeriksporten, and is divided into two parts. Part 1 is a study of literature about grouting in rock. Part 2 describes the grouting works over a section of 1,5 km of the Romeriksporten tunnel. The chosen section is situated right under the two lakes Lutvann and Puttjern in Østmarka, a public forest east of the centre of Oslo. No grouting works were planned here, but great water leakages made systematic pre-grouting necessary. The use of different grouts, routines and decision-making are considered. It seems like the preliminary investigations of the hydrogeology was not good enough. The potensial of great leakages was underestimated. Despite intense pregrouting, with different grouts, repeated rounds of grouting and different methods, the results in this section were poor. The fast changes in rock- and leakage conditions are considered as the main reasons. Beneath Lutvann and Puttjern, post-grouting was also necessary. These works will not be finished until spring 1998. The final results of the grouting works are therefore not known yet. The aims are to decrease the water leakages to an acceptable level, and to reestablish the ground water balance in Østmarka.

Halleland, Ine (T. Myran)

Sikkerhet på norske fjellanlegg. Safety at Norwegian Tunneling sites..

Hauklien, Ragnar (K.L. Sandvik / Svedala)

Oppredning av brukt asfalt og betong. Principles and Practice in demolished Asphalt and Concrete Processing. Efficiency reqiurements in the building industry has precluded the recirculation of building materials. Now pressure upon available dumping areas as well as energy efficiency start to reverse this situation. The availability of useful equipment is important to make recirculation ecconomical. In this thesis a mobile plant built by Sveala was investigated.

Heieren, Kristina (E. Roaldset)

Forsegling langs diagenetiske heterogeniteter i juraiske reservoarsandsteiner med vekt på kvantifisering av kvartssementering langs mikroforkastninger og styolitter. Seals along diagenetic heterogeneties in Jurassic reservoir sandstones, with emphasis on assessing quartz cementation along micro-faults and styolites.

Helberg, Dag (B. Brattli)

Grunnvannsmodellering - Simulering av oppryddingstiltak for jetfuel-forurenset grunnvann. Ground water modelling. Simulation of site remediation in jetfuel polluted ground-water.

97 Institutt for geologi og bergteknikk Hovedoppgaver 1997

Holter, Susanne A. (K.L. Sandvik)

Biologisk behandling av oljeforurenset jord. Bioremediation of Oil Contaminated Soil. Active Composting with addition of Biosurfactants, Nutrients and Bacterias. Cheap methods to clean up small areas of soil contaminated with oil like gas station sites are sought. In this wor an offsite method where the soil was placed in containers for biological degradatoin of the oil was tested out. the influence of biosurfactants, nutrients and bacteria were tested both in the field and the laboratory. The conclution was that the soil probably contained oil consuming bacterias at the location. Proper areation and mixing were therefore the critical factor for a rapid cleaning of the soil.

Jensen, Atle Jahn (B. Nilsen / Statens Vegvesen Hordaland)

Tunnel til Horsøy - Ingeniørgeologisk analyse. Tunnel to Horsøy - Engineering geological analysis. Based on available background material, field mapping and laboratory testing, engineering geological evaluation and planning of a road tunnel system at Horsøy, including underground roundabout, have been carried out. The tunnel system has a total length of about 1.5 km. Stability, rock support requirement and cost are in focus in the evaluations. Potential use of the tunnel muck as well as additional use of the tunnel for public shelter, water pipes etc. are also discussed. It is concluded that this project is feasible technically as well as economically.

Johannessen, Fredrik (E. Broch)

Utforming og sikring av kraftstasjoner i berg. Design and support of underground hydropower stations. Along the Nea – Nidelv river in the county of Sør-Trøndelag 8 underground hydropower stations have been constructed, the oldest dating back to 1957 and the latest commissioned in 1989. The thesis describes the geological and rock mechanical conditions for these caverns, and gives details about the size and shape. Special emphasis is put on the rock support. Comparisons with 24 other hydropower caverns in Central Norway are also made. It is concluded that different companies have different solutions to similar rock engineering problems.

Kjennerud, Tomas (S. Lippard / IKU)

Structural restoration of paleobathymetry during the Cretaceous in the Northern North Sea Four scenarios for structural restoration have been developed: involving no tectonic activity, tectonic activity, tectonic activity with tilt and laterally variable subsidence. In addition, the restorations have been based on all indicators that can give any information about paleobathymetry. These restoration scenarios have been used to restore the Cretaceous paleobathymetric evolution on four section lines in the northern North Sea. The results from these four restored seismic lines have been used to construct five paleogeographic maps for the Cretaceous. The Cenomanian is found to have been a time of anomalous subsidence and sedimentation rates. This may indicate a tectonic event in the northern North Sea at this time.

Klungen, Marit (E. Broch)

Utforming og sikring av kraftstasjoner i berg. Design and support of powerstations in rock. In the county of Nord -Trøndelag 12 underground hydropower stations have been constructed, the oldest dating back to 1946 and the latest commissioned in 1994. The thesis describes the geological and rock mechanical conditions for these caverns, and gives details about the size and shape. Special emphasis is put on the rock support. Comparisons with 24 other hydropower caverns in Central Norway are also made. It is concluded that different companies have different solutions to similar rock engineering problems.

Kristoffersen, Marte (T. Malvik)

Evaluation of Pegmatites in the Glamsland Area. The work has been carried out in cooperation with North Cape Minerals, Lillesand which produces quartz and feldspare concentrates as well as minor amounts of biotite. Several outcrops of pegmatites are evaluated in order to assess the future potential as resources for quartz and feldspare production. The results show that some of the pegmatites may be

98 Institutt for geologi og bergteknikk Hovedoppgaver 1997 a future resource if only the mineralogy and chemical composition is considered. Drilling is needed to determine the volume and tonnages of the pegmatites.

Larsen, Stine (E. Broch)

Numerisk analyse av de fjellmekaniske forhold under varierende trykk for gasslagringskaverne i steinsalt. Numerical study of the rock mechanical conditions in rocksalt under variable cyclic pressure. This thesis is part of a research cooperation between NTNU and Bergakademie Freiberg, Germany. A cavern with a diameter of 140 m and a height of 170 m at a depth of more than 500 m has been modelled. Rock stresses and deformations during one year of operation with varying internal gas pressure have been studied.

Lie, Hege Ann (K.L. Sandvik / N. Veritas)

Norsk oljevernteknologi – vurdering av miljørisiko, effektivitet og kost-nytte. An evaluation of the Norwegian oil spill prevention system. Cost/benefit and hazard assessment. This work takes a closer look at the Norwegian oil spill prevention system. A risk analysis progaram MIRA, developed by Det Norske Veritas, is presented and used for evaluation of the risks and prevention possibilities obtainable. It was for example found that the weathering characteristics of different oil types gave very different situations regarding the seriousness of oil spills.

Lomheim, Line Sissel (B. Brattli)

Hydrokjemisk beskrivelse av submorene grunnvannsmagasiner på Låg-Jæren. Hydrochemistry in subtil groundwater magazines at Låg-Jæren. The candidate has evaluated the groundwater quality in three areas (Skjetting, Aulestad, Grødaland) at Låg Jæren, especially with emphasis on contamination from faring. The study has revealed that the water chemistry is partly a consequence of weathering of silicates/carbonates and partly from flowing through sediments with fossil salt (high content of Na+, Cl). There is no sign of contamination from pesticides, but the nitrate level is fairly high, reflecting a certain influence from farming. Based on isotope studies (18O and 2H) it is concluded that the source for formation of groundwater is from precipitation and that the contribution from rivers and lakes is of minor importance in these areas.

Madslien, Gro (S.O. Johnsen / N. Hydro)

Sensitivitet av input-parametre i bassengmodellering - et eksempel fra Tail End graben, Nordsjøen. Sensivity of input parameters of basin models for the Tail End Graben, North Sea. Based on well data from the Tail End Graben a basin modell has been established. Vitrinite reflectance data, temperature data, and to a certain extent sterane and hopane isomeric data are used for calibration. Sensistivity analysis has been performed for : heatflow, basement thickness, lithology, salt tectonics, SWI-temeprature, paleo waterdepth, and age.

In the sensitivity analysis the transformation ratio T50 has been used as a quantitative expression for the sensitivity of variation of input parametres. It is found that the model is most sensitive to changes in heatflow. Realistc changes in basement thickness, lithology, salt tectonics, SWI-temperature, and paleo waterdepth have only minor influence. A change in age is more sensitive.

Moksnes, Stine Radmann (T. Myran)

Vegslitasje og svevestøv. Road abrasion and road dust.

Riddervold, Hans Ole (K.L. Sandvik)

En undersøkelse av potensialet for redusert energiforbruk i ren prosess scrap (CPS) loop. An investigation of the potential for reducing energy consumption in the clean process Scrap (CPS) Loop. This work was carried out in Norsk Hydros remelting plant for process scrap in Clevaux , Luxemburg. An investigation of the energy consumption in the aluminium recirculation cycle showed that the melting process dominated completely. It

99 Institutt for geologi og bergteknikk Hovedoppgaver 1997 was originally assumed that the transportation of scrap was an important enery consunmer. This is still true, but at the present easier obtainable energy savings can be obtained by concentrating upon smelting.

Ringdal, Fredrik (K.L. Sandvik)

Bruk av synk-flyt separasjon til rensing av aluminiumskrap. Heavy medium separation of aluminium scrap. Practical testwork was carried out to evaluate the effect of heavy medium separation on the cleaning of aluminium scrap. A small plant was built up where the medium was kept in suspensioon by pumping in closed loop. The tests were carried out in a batch mode. The purpose of the tests were to remove impurities such as copper lead as well as light substances like plastic. A good cleaning was possible, but the test rig had ts limitatiions. Care has to be taken to avoid contamination of the cleande aluminium by ferrosilicon.

Rokke, Jørn (S. Lippard / NGU)

Dyp til grunnfjell I nordlige Nordsjøen, tolket fra seismikk og magnetometri Depth to basement in the northern North Sea, interpreted from sesimic and magnetic data Depth to crystalline basement has been mapped between the Øygarden fault zone in the east and Tampen Spur in west, between 61o and 62o. The Selje High is a rotated basement block related to the development of the Møre-Trøndelag fault zone. It is about 4 km deep and represents the eastern part of a west-dipping half graben. The basement comprises the same rocks as the Western Gneiss Region. Marflor Ridge, where the top basement is about 6 km deep, is bounded by Permo-Triassic and Jurassic faults. From the strong magnetic anomalies, it may be composed of gabbro. Basement highs in the southern part of the Måløy Terrace show a trend of magnetic lineaments which can be followed from known faults and detachments on land. The basement here correlates to the upper/middle allochthon of Caledonian age.

Rubagumya, Constantine (NORAD / A. Myrvang)

In-situ rock stress pattern as a decision making tool at the Lower Kihansi Hydropower Project, Tanzania. A case study. A theoretical and practical analysis of stress measurements carried out by SINTEF, indicate the minimum principal stress is in the order 10 Mpa, showing that a pressure system with a head 8.5 Mpa is possible in this case.

Sandem, Camilla (T. Malvik)

Utvikling av kalkbasert maling/slemmemasse. Development of carbonate-based painting. The work has been carried out in co-operation with Franzefoss Bruk. The aim was to develop a “self-cleaning”, light coloured paint to be used on tunnel walls. Using raw materials produced from Franzefoss Bruk own carbonate deposits also was a major objective.

Seter, Hanne A. (R. Sinding-Larsen)

Varmeledningsevne i sedimentære bergarter. Utvalgte prøver fra den norske kontinentalsokkelen. Thermal conductivity of sedimentary rocks. Selected samples from the Norwegian Continental Shelf.

Shrestha, Manohar (B. Nilsen / NORAD / Nepal. Statskraft Anlegg)

Cavern stability analysis in Khimti underground powerhouse, The design of the powerhouse cavern at Khimti I hydropower project is discussed based on review of available background material, empirical methods and numerical modelling (including UDEC analyses). Two possible powerhouse cavern geometries are considered: ordinary horseshoe shaped and an alternative with the lower portion for tail water. It is concluded that in this case numerical modelling is a good tool for analysing the mechanism of potential stability problems.

Sinh, Tran Dinh (B. Nilsen / NORAD / Norconsult)

Support requirement and stability analysis of the tunnel system at Neelum-Jhelum Project in Pakistan. Stability and rock support requirement of the tunnels at Neelum-Jhelum hydroelectric project in Pakistan are analysed based on available background material. Particular emphasis is put on the applicability of shotcrete in the high water

100 Institutt for geologi og bergteknikk Hovedoppgaver 1997 speed (approx. 3.5 m/s) headrace tunnel. It is concluded that for economical as well as technical reasons, a combination of rock bolting and shotcreting represent the optimum support alternative.

Skytterholm, Odd Tore (B. Brattli / NGU)

Bergartens innvirkning på jordforsuring i Nord-Trøndelag. The Relationship between bedrock composition and acidification of soils in Nord-Trøndelag County, Norway. 633 samples from the humic layer and 233 samples from brown earth were used in this project. The samples were extracted with H2O and dilute sulfuric acid (pH3). The contents of Mg, electric conductivity and pH were determined. The defined factors Fa and Fr, which expresses the soils sensibility to acidification, were estimated based on pH values determined in H2O and dilute acid extractants. The main aim of this diploma was to investigate the bedrock compositions influence on soil acidification. The contents of organic matter in the soil samples were not determined, which make the interpretations complicated. The results indicates lower pH values in the humic layer because of various bedrock composition and it seems clear that the pH in brown earth varies with the bedrock composition. Base cations from sea salt deposition is probably the reason why pH value is higher in the humic layer for the areas close to the Atlantic ocean. Sea salts in precipitation causes also higher contents of Mg and higher electric conductivity for the brown earth samples in the regions close to the sea.

Sokn, Astrid (S. Lippard / Phillips)

Stordbassenget - geologisk rekonstruksjon. 3D Tertiary stratigraphic and structural restoration to determine maximum burial for the Mesozoic source rock interval, using 3D Move, in the Horda Platform, Norwegian North Sea. The late Tertiary stratigraphy of the Horda Platform has been restored by removing tilting and the effects of sediment compaction, to produce palinspastically restored top source rock (Base Cretaceous) interval maps. Four sequential stages were used to restore the model to the Middle Miocene level. Depth differences between the present day Base Cretaceous (minus the waterdepth) and the sequentially restored Base Cretaceous surfaces show that the time of maximum burial, and also the time of maximum source rock maturity, should source rocks be present, was Mid Miocene.

Svendsen, Magnus Grønbech (S.W. Danielsen)

Produksjon og bruk av knuste steinmaterialer i Franzefoss. Production and use of crushed aggregated at Franzefoss.

Sylte, Brit (K. Nielsen)

Vurdering av fremtidig produksjon av kystsikringsstein og pukk ved Franzefoss Bruk AS, avd. Valberg. Assessment of the long term production of reprap and crushed aggregates at Franzefoss Bruk, Valberg division. The topic of the work has been to assess available resources for the production of rip-rap and armour stone for erosion control, and the production of crushed aggregates for asphalt pavement. The resource assessment then formed a basis for discussing various strategies with regard to product blends and production capacities in the crushing an d screening plant. The investigations were done for Franzefoss Bruk AS in a quarry that produces rock materials mainly for export.

Sæl, Solveig (E. Roaldset / N. Hydro)

Diagenetisk modenhet i relasjon til oppløft. Kvantitativ modellering av sen terrtiær oppløft/begravningshistorie. Diagenetic maturity in relation to uplift; quantification of late Tertiary uplift/burial history.

Tefera, Tewodros Haile (E. Broch / NORAD)

Prediction of Entoto Tunnel Support in Ethiopia. To transfer water from Gerbi dam and Sibilu dam to Addis Ababa in Ethiopia a combined transmission scheme including a tunnel through Entoto ridge is proposed. The proposed tunnel, horseshoe shape, 3.75 m wide by 3.3 m high, length 4450 m is located at the northern extension of Addis Ababa. Design flow of 750,000 m3/day (8.6 m3/s), open channel, flow is the proposed design criteria for the tunnel. The main task of the thesis is to study and use the geotechnical investigation data for characterization of the rock mass in the project area and to predict the type of rock support required in Entoto tunnel at the pre-construction stage, using empirical design method. Based on the two most commonly used empirical methods, the Q-system and RMR method, in

101 Institutt for geologi og bergteknikk Hovedoppgaver 1997 rockmass classification and rock support estimation, the Entoto Tunnel project area is evaluated. The tunnel support prediction based on Q-system requires less support than those predicted based on RMR.

Vikane, Kjetil (B. Nilsen / AF Spesialprosjekt a.s)

Deponi for lavt- og middelsaktivt atomavfall, Hindalen - Analyse av bergmassekvalitet og sikringsbehov. Repository for low and intermediate level nuclear waste, Himdalen - analysis of rock mass quality and rock support. A facility for storage and disposal of low- and intermediate level nuclear waste is built at Himdalen in Aurskog-Høland. The facility is planned to be completed by March 1988, and will consist of 4 parallel caverns, each 50 meters long. Based on available background materials, and detailed field mapping, including rock mass classification according to the Q- method engineering geological analysis and evaluation have been carried out. Particular emphasis have been put on rock support requirement, and the distribution between preliminary and permanent support. Safety during construction and design principles are also key words.

Østenstad, Heidi (K.L. Sandvik / Statoil)

Kartlegging av energiforbruk og utslipp til ytre miljø i forbindelse med drift av gasstransportsystemer. Map of energy consumption and emission to the environment connected to the running of gastransport systems. The object was to make an overview of the consumption of energy, production of waste and emmissions to air and water by the Transportation Network especially for the Draupner field and transport to Germany and Belgium. Another task was to implement the Terrea Environment Acount system and use it on the data collected. A result of the work is that the emmisions to the environment are small and fulfills the regulations given. The emmisions of CO2 and NO x were the most serious. Better energy efficiency in the transportation system will help here.

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1996

Adil, Ali O. (S.O. Johnsen / NORAD)

Seismic stratigraphical analysis of a Late Pliocene clastic wedge in the Bjørnøya West province, Western Barents Sea. The “wavy” seismic facies within the Late Pliocene clastic wedge in the Bjørnøya West exploration area (Bjørnøya Through) in the southwestern Barents Sea have been investigated using data from one single exploration well and seismic profiles. The studied interval has been divided into three seismostratigraphic informal units which are in turn divided into sub-units and further into seismic facies. A number of megaripples/sandwaves and ridges, partly with internal reflections resembling forsets, are mainly confined to two N-S trending intervals within the clastic wedge. The wavy reflectors in the lower part of the clastic wedge represent ridge bedforms with heights of more than 50m and lee-side slope angles of 3 to 6 to the southeast (upstream of assumed overall paleo sediment supply direction) The seismic facies of the upper part represents megaripples/sandwave bedforms with lee side slope angles of 9 to 11 to the southeast (upstream). The middle part of the wedge on the other hand, consists of parallell reflectors, with some deformation in the east (proximal part). The sedimentological model suggested for the upper and lower parts of the clastic wedge is a storm dominated shelf grading into shorface and glaciofluvial environments to east, and possibly a glaciomarine environment for the middle part.

Andersen, Lars, Atle (K.L. Sandvik / RIT / Franzefoss Bruk)

Demolition of the University Hospital of Trondheim (RIT), a pilot survey on reuse and recycling of building materials. (Skjæveland, Rolf) It is decided to Demolish the present regional hospital in Trondheim and erect a new one at the same site. This is the first attempt to evaluate reuse of the building components. One typical sector of the hospital was used for a case study.

Aryal, Krishna (B. Nilsen / NORAD / Statskraft Anlegg)

Stability and rock support of tunnel portals, Khimti Hydropower Project, Nepal. For the underground powerhouse and the 12 km of tunnels at the Khimti Hydropower Project, several adits and access tunnels are excavated. As a result of the difficult topographical and geological conditions at the site, the stability of the portals is a major concern. The stability is analysed based on review of geological data, stereographical analyses and limit equilibrium methods.

Christensen, Morten (B. Nilsen)

Blast vibrations - Romeriksporten tunnel. Comprehensive review and analysis of recorded blast vibration data have been carried out for the Romeriksporten railroad tunnel. Main emphasis is put on potential correlations between vibration magnitude and engineering geological conditions, including foundation conditions. It is found that to a great extent geological structures like foliation, filled joints and dykes may influence on the magnitude and characteristics of the vibrations.

Djuvsland, Jan Olav (B. Nilsen / St. Vegvesen Hordaland)

The Folgefonn tunnel - Definite plan study. Detailed engineering geological investigation and planning have been carried out for the planned Folgefonn road tunnel. In the field all relevant factors likely to affect stability and tunnelling conditions have been recorded. Laboratory testing to find the most relevant mechanical properties is also carried out. Detailed prognoses for tunnelling cost and time consumption are presented. The high rock stresses most likely represent the main challenge for this project.

Engelien, Erik (J.L. Sollid, UiO / E. Roaldset, Cand.scient.)

Block fields and permafrost, Tronfjellet, S.E. Norway and preservation of the blockfields. In Norway block fields and permafrost are common features in the mountain regions. The peak and surrounding areas of Tronfjell (1665 m o.s.l.) consist of block fields with lower limit ranging from 1300 to 1450 m o.s.l. Permafrost areas are scattered at altitudes above 1625 m o.s.l. It was not possible to confirm the original working hypothesis that the

103 Institutt for geologi og bergteknikk Hovedoppgaver 1996 blockfields were partly products of preglacial weathering. However, for the sand, gravel and silt sized material in the soils between and below the blocks, an origin of glacial till mixed with preglacial weathering products were assumed.

Fure, Hallgeir (T. Prestvik)

Mineral resources in the Leirgulen-Davik area of Bremanger, West Norway, with emphasis on the resource talc, soapstone and olivine. The ultramafic rocks in the Kleberga area near Davik, which occur as separate lenses concordant with the regional foliation, have been evaluated as potential sources for talc and soapstone. The rocks are alpine-type peridotites of dunitic composition, which have been partly altered to serpentinite. Along some of the borders and in a few internal zones the serpentine has been altered to talc and carbonate. It is estimated that the lenses carry 1 million metric tons (Mt) of talc-carbonate rock. However, on the basis of the narrow zones of mineralization (< 4 m), and the relative inaccessability of the area, combined with only suboptimal whiteness of talc, it is concluded that the lenses are not ecconomically exploitable. A dunitic body of alpine type at Gamlesetra, Endal has been estimated to carry 2.2 Mt of olivine. Even though this dunite is much less altered than the lenses at Kleberga, it is conluded that the deposit is not ecconomically interesting to-day. The tonnage is too small, and the availability of other, much larger, high-quality olivine deposits in the same general area supports this conclusion.

Hadland, Åsne Hoff (K.L. Sandvik)

The preliminary Characterization of an Area with oil contaminated Soil and the Potentials of clean-up using ioremeditation. There are a lot of heavy oil contaminated sites in the Baltic. In this work such a site was visited, sampled and the samples analyzed and evaluuated.

Hartz, Andreas (T.Thorsen / H. Ødegaard / Inst. for vassbygging / R. Sinding-Larsen)

Ultrafiltering of humic drinking water. The purpose of this thesis was to study membrain filtering techniques for removal of organic matter from humic drinking water. Filtering at the laboratory scale was conducted on seven types of humic drinking water (both humic concentrates and natural humic matter was used). Water was sampled from Sør-Trøndelag. Humic types were chosen in relation to the position of the drainage area (hight above sealevel, topography, vegetation and geology). Results show that membrain filtering is a suitable method for the treatment of humic-rich sufficial water from Sør-Trøndelag.

Haugen, Inge Martin (K. Nielsen / Elkem)

Crushing and screening of silicon materials. Optimization by computer simulation The thesis presents an optimization study of the crushing and screening operation at a metallurgical plant producing silicon metal. The results are, however, proprietary information of the company.

Humbernes, Frode(T. Myran / Miljølab AS)

Development of turf based building insulation. A process for the treatment of raw turf to make it applicable as building insulation is developed. The method is based on the natural binding power of moisten raw turf. The pelleted turf has low thermal conductivity, but not as low that it can compete with the insulation products traditionally used. It seems probable, however, that the quality of the turf product can be improved by further developing the production technique. For producing a commercial product the drying process must be improved and the costs lowered.

Islam, Md. Shafiqul (S. Lippard / NORAD)

Seismic sequence stratigraphic study in the Balder area, North Sea.

The seismic sequence stratigraphy of the Paleocene and Eocene sections of the Balder were studied with the help of seismic data, well completion logs, core data and biostratigraphic data. This is used to find sequence and parasequence boundaries and their relative truncations, onlaps, offlaps, baselaps, etc. The results provide information about depositional environments and used to make seismic facies maps within the study area.

104 Institutt for geologi og bergteknikk Hovedoppgaver 1996

Jin, Weicheng (E. Broch / Lu Ming / NORAD)

Numerical Study of Stability of Underground works at Xiaolangdi , Multipurpose Dam Project, China.

The Xiaolangdi Multipurpose Dam Project is located on the Yellow River. It is one of the largest hydropower projects under construction in China. The underground powerhouse contains six generating units with a total installed capacity of 1,800 MW. It is 251.5 m long, 26.2 m wide and 61.4 m high with the rock cover of 75  95 m. The rock is flatlying sandstones and is of good or fair quality. The thesis is aiming to analyse the stability of Xiaolangdi underground powerhouse and adjacent caverns by the Universal Distinct Element Code (UDEC), which is a widely used numerical tool in rock engineering. A finite element program - ABAQUS was used for studying the effect of rockmass anisotrophy. The study reveals that the stability of the walls is more crucial than the crown of powerhouse.

Kidega, Grace M. (E. Broch / NORAD)

Reservoir Slope Stability. Lower Kihansi Hydropower Project, Tanzania. The Lower Kihansi Hydropower project is owned by Tanzania Electric Supply Company Limited (TANESCO). The project comprises a gross head of 853.5 m development on Kihansi river, and has been planned as a 180 MW plant. The Lower Kihansi includes a water storage reservoir with area 261,000 m2 and volume of 1,616,000 m3. The maximum reservoir daily regulation rate for step 1 (180 MW) is estimated to be 2.5 m/day and for step 2 (300 MW) approximately 5 m/day. The objective of the study is to assess the possibility of slope instability involving reservoir regulation, the raise in ground water level and pore pressure during the rain season. Its other objectives, is to analyse slope stability and recommend the remedial measures for stabilizing them. The study, which included comprehensive field investigations show that the risk of reservoir slope instability is very high in the steep sections of reservoir slopes.

Kjæreng, Gøril M. (R. Sinding-Larsen)

An evaluation of the exploration in the Barents Sea. The main objective of the thesis is to evaluate the play risk in the Norwegian part of the Barents Sea. The thesis has described play probabilities and the expected success rate in the confirmed and unconfirmed play models which are defined on the basis of seven stratigrafic levels by the Norwegian Petroleum Directorate (NPD) with the main emphasis on play models in Paleozoicum and Triassic. The large play models defined by NPD have been devided into sub-play in order to better describe the individual probabilities which effects the play probability and the expected success rate. A systematic documentation of the justifications for the individual risk factors have been drived in order to be able to treat risk in a consistent way. The results show that play models in sandstones of Triassic age has the highest play probability and success rates followed by the play models in late Paleozoic carbonates. Lowest play probability and unexpected success rates was estimated in play models of Tertiary age. The estimates derived in this thesis are generally higher than corresponding figures from NPD, but the results are not directly comparable due to different definitions of play area.

Kleiv, Rolf Arne (K.L. Sandvik / Statsskog FS)

Development of mine water at the Tverrfjellet mine. A theoretical/practical evaluation of the composition of runoff from the abandoned Tverrfjellet mine was made. By combining existing hydrological data, an estimate of when the mine would be filled up was also undertaken. This work shared the award for the best environmental thesis in engineering from NTNU in 1996 with one in the subject of ventilation.

Liu Libin (S. Lippard / NORAD)

A study of faulting and directional permeability on basin to reservoir scales. Faults play an important role in fluid flow on the basin to reservoir scale. It is therefore important to determine the position and size of faults as accurately as possible. The limitations of the seismic method result in three problems of fault recognition: The first is that the number of small faults with displacements below seismic resolution cannot be easily determined. The second is that the real length of known faults cannot be measured. The third is a mapping problem in that some fault cuts, even where their displacements are above seismic resolution, cannot always be unequivocally connected with those of the neighboring lines because of the limitations of lateral resolution. Two 3D seismic structure maps from the Gullfaks and Heimdal areas of the North Sea basin are employed to investigate these kinds of problems.

105 Institutt for geologi og bergteknikk Hovedoppgaver 1996

The structure horizons of the maps are mid-Jurassic. Through a quantitative analysis of known fault parameters, several new models and mathematical distributions are tested.

Midtbø, Elisabeth (A. Myrvang)

Relation between in situ rock stress and groundwater flow in rock. Based upon comprehensive mapping of structures and water flow in tunnels and road cuttings, and in situ rock stress measurements by hydraulic fracturing in four locations in NW Norway, a clear trend was seen between groundwater flow and the direction of maximum horizontal principal stress, with maximum flow parallel the maximum stress.

Moe, Eirik (E. Broch)

Design and support of underground powerhouses. Engineering geological mapping of 12 underground powerhouses belonging to Sør-Trøndelag Kraftselskap have been carried out. The oldest powerhouse dates back to 1950s. A study of the rock support of the powerhouses shows that the design has changed from a heavy use of concrete structures to an increasing use of the rock itself as a reliable structural element.

Moldstad, Lars (K.L. Sandvik)

Oxygenation of ground water by air sparging for bioremediation. Practical tests as well as theoretical calculation of the use of air sparging to supply oxygen to microorganisms as a way of removing organic pollution from the soil was carried out.

Olafsen, Rikke (K. Rokoengen / Geofuturum)

Treatment of heavy metal- and oil-containing waste water in bark / LWA-filter. Waste water contaminated by heavy metals is a growing problem in many fields of industry. Waste water from workshops in addition often contains large concentrations of oil. Soil is able to hold back contaminations from infiltrated water by mechanical, biological and chemical processes. Both organic and inorganic substances contribute to this treatment. In the thesis an artificial soil made up of bark and LWA (light weight aggregates) was tested in laboratory scale. The results indicated clearly that the combination is an excellent media for removal of both heavy metals and oil. The results are used in full scale at the Rena Leir.

Rognlien, Tone E. (S.O. Johnsen / N. Hydro)

Sequence stratigraphic Analysis of the Deposits in the Viking Group (Upper Jurassic) on the Lomre Terrace, northern North Sea. The thesis is confidential, abstract not available

Ryacudu, Rudi (NORAD / S. Lippard)

Structural analysis of the Stord Basin, North Sea. The Stord basin is an extensional basin formed during a Permo-Triassic rifting phase. The southern part is affected by the offshore extension of the NE-SW trending Hardangerfjord Shear Zone that exhibits a complex faulted transfer zone geometry. The area consisted of a deep isolated basin during the Triassic, as shown by the absence of Triassic sediments outside the main rift. From Jurassic time onwards the area became part of the regional North Sea basin and was little affected by mid to late Jurassic extension. In the late Cretaceous-earliest Tertiary the area was subjected to mild compression that resulted in the formation of inversion anticlines and fault reactivation in the southern part of the area. The eastern part of the basin suffered uplift in the Cenozoic, starting in the Paleocene-Eocene. Renewed uplift took place in the late Oligocene and later resulting in erosion of much of the Tertiary and Mesozoic sediments in the eastern part of the area.

Røst, Siri (S.O. Johnsen / Statoil)

Sequence stratigraphic interpretation of the Tertiary succession on the Trøndelag Platform between 65o and 66oN. Based on conventional seismic data and data from 3 wells a sequence stratigraphic interpretation of the Tertiarty deposits on the Trødelag Platform has been performed. A sequence stratigraphic framework has been established in

106 Institutt for geologi og bergteknikk Hovedoppgaver 1996 addition to a model for the Tertiary geologic evolution of the area. This is put into a wider connection, and mechanisms governing the relative sealvevel changes on the shelf outside Mid Norway have been suggested. In the Paleocene a transgression started due to subsidence of the Trøndelag Platform. The transgression lasted to mid Eocene an was interrupted by three relative sealvel falls in Paleocene, due to uplift of the mainland. In mid Eocen the transgression stopped due to continuing uplift of the mainland. In mid to late Eocene two relative sealevel falls occured. Tectonic activity realted to the opening of the Norwegian - Greenland Sea led to faulting of the Paleocene, Eocene, and lower Oligocene sediments in two phases. At the transition between Eocene and Oligocene the uplift of the landmass continued, resulting in a major fall in sealevel. Oligocene deltaic sediments were deposited due to the combined effect of eustaic sealevel changes, subsidence and uplift of the landmass. In early Miocene a major phase of uplift started. This uplift lasted to mid Miocene resulting in a major relative fall in sealevel. In late Miocene to early Pliocene a major rise in sealevel occured due to the continous subsidence of the Trøndelag Platform along with uplift of the landmass to the east. During Pliocene an icecover covering parts of the studyarea deveolped, and thick wedges of sediments were deposited by glaciofluvial and glaciomarine processes. These deposits have later been eroded and transported by the ice that moved over the deposits.

Skjæveland, Rolf (K.L. Sandvik / RIT / Franzefoss Bruk)

Demolition of the University Hospital of Trondheim (RIT), a pilot survey on reuse and recycling of building materials. (Andersen, L.A.) It is decided to demolish the present regional hospital in Trondheim and erect a new one at the same site. This is the first attempt to evaluate reuse of the building components. One typical sector of the hospital was used for a case study.

Stokke, Lisbeth (K. Nielsen)

Resource management in relation to excavation of river sands and gravels. The thesis presents a study on the legislation and regulations with regard to the management and exploitation of fluvial aggregates in Norway, and how these regulations may be applied differently by local authorities. The study also presents an environmental impact study, which in a general way, compares the exploitation of fluvial aggregates and the production of crushed aggregates from conventional quarrying.

Strand, Sigrid Melby (K. Nielsen)

An investigation into practical decision criteria regarding the selection of environmentally friendly materials during the building process. Several models have been developed in order to facilitate the selection of environmentally friendly construction materials. The thesis examines some of these models, but does not find any of them very practical for day to day decisions, and they don‟t take costs into consideration. The thesis proposes a relatively simple and practical model which allows a weighted comparison of different environmental parameters coupled with costs. The basic idea is to make the “best” environmental selection of materials within a restricted economic framework.

Thowsen, Nina Østborg (E. Roaldset)

Relation between compaction and pressure in Cretaceous Mudrocks at the Halten Terrace. The thesis consist of a literature review of compaction of mudstones and shales and a study of data from well logs and well tests. Selected intervals of the Cretaceous sediments in the Haltenbanken area are studied with respect to pressure conditions and pressure development with depth. The pressure data are related to stratigraphy, lithology and mineralogy. At depths less than 2.5-3 km the compaction can be related to pressure at larger depths such correlation are doubtful.

Toivakka, Eero (Neste Petroleum / Norplus / M.Sc. thesis. Roaldset / H. Papunen / Åbo University)

Late Palaeozoic structural and sedimentary development of the Finnmark East area in relation to sub-global plate tectonics. The objectives were to clarify the main structural and sedimentary factors influencing the prospectivity of the Palaeozoic sequences in the Easternmost Finnmark Platform. A model of the development of the North Atlantic region in the Palaeozoic time was reconstructed, based on four partially dissimilar models, and on individual observations reported in land areas. The most important plate tectonic events that influenced the geological development of the East Finnmark

107 Institutt for geologi og bergteknikk Hovedoppgaver 1996

Platform are outlined. The sediment distribution in Palaeozoic time was controlled by Baikalian and Caledonian basement faults, sea level variations and by Carboniferous faulting and uplift. The geological history through this period discussed in a petroleum geological context.

Tyssekvam, Ingvar O. (B. Nilsen / NSB Gardermobanen)

Weakness zones in Romeriksporten tunnel - Probing and characterisation of swelling material. Faults and weakness zones intersecting the Romeriksporten railway tunnel are described. For some selected zones swelling pressure and other relevant parameters are analysed in the laboratory according to standard procedures. Particularly, representativity and repeatability are studied and discussed in this connection. As a part of the work, an oedometer for testing intact material has been developed. The initial test results based on this new equipment are promising.

Tømmerås, Rolf Are (S. Lippard / Statoil)

Modelling of oil and gas generation in overpressured areas on the Norwegian continental shelf. Implications for sealing and leakage. The fact that all of the reservoirs in the overpressured region of the Haltenbanken area are water-bearing, as opposed to reservoirs in the eastern (normally pressured) part, has led to the assumption that the high overpressures in the west caused the hydrocarbon accumulations to fatally leak. The modelling results reveal that the general charging trends of the Halten West structures differ from the trend in the Northern North Sea, with the latter structures being characterised by continual charging throughout the Tertiary, compared to two main generation periods, one in the Late Cretaceous and one in the Plio/Pleistocene, in Halten West.

Undseth, Ellen (K. Rokoengen)

Tunnel with shotcrete lining in soft soil - example from railroad tunnel at Eidsvoll.

In Eidsvoll, about 60 km north of Oslo, a soft ground tunnel is being made for the NSB Gardermobanen A/S. The ground consisted of marine deposits of clay and silt and especially water bearing layers of silt was a great challenge during excavation. 126 m of the tunnel collapsed during construction. The excavation method used, NATM, or “Sprayed concrete linings for tunnels in soft ground” is evaluated. It is concluded that the method can be used in soft soil if the ground has enough strength to keep its shape before the lining is established.

Wang, Hui (B. Nilsen / NORAD / AGN)

Long-term deformation of the permanent ship lock of the Three Gorges Project in China. For the Three Gorges Project a double lane, five-stage permanent ship lock with slope height up to 170 m is under excavation. Due to the operation of the gates, only very small convergence of the rock slopes can be tolerated. The convergence is analysed based on empirical and numerical (UDEC) methods. Based on these analyses, the maximum creep convergence of the ship lock wall is approximately 10 mm.

Wiig, Hanne Elisabeth (K. Nielsen / Nikkel og Olivin AS)

Feasibility study of the Nordmalm deposit, Nikkel og Olivin AS. The purpose of the study was to investigate whether the Nordmalm part of the Ballangen nickel deposit can be economically exploited. The work included tonnage and quality estimates as a basis for a technical and economic analysis. The results are, however, proprietary information of the company.

Wiig, Torgeir (B. Nilsen / Veidekke)

The North Cape tunnel - Engineering geological conditions. Based on own field mapping and available background material, a comparison is made between engineering geological conditions and rock quality as seen on the surface and as experienced in the tunnel. Generally high degree of jointing combined with chlorite and clay filling of the joints are found to be the main reasons of the stability problems. A prognosis of rock mass quality of the remaining part of the tunnel is presented.

108 Institutt for geologi og bergteknikk Hovedoppgaver 1996

Yri, Torbjørn (E. Broch)

Long term quality of shotcrete in road tunnels subjected to high rock stresses.

Geology and stress conditions as well as the quality of shotcrete in several road tunnels have been investigated. It is concluded that the unreinforced shotcrete applied as long back as in 1963 is of a better quality than the steel fibre reinforced shotcrete applied in the 1980‟s. There may be an increasing tendency to rely too much on the shotcrete and to neglect the need for rock bolts in tunnels with high stresses.

Ytterås, Erling Kr. (K.L. Sandvik)

Eddy Current Separation - Background, Mapping of Central Aspects, and Preliminary Test concerning the Cleansing of Aluminium Scrap. The use of an eddy current separator to clean aluminium scrap was investigated. The purpose was see if the separator could be used for separaion of conductors like copper and aluminium and also to build up expertise on this field in Norway. The work was therefore systematically carried out on different size fractions shape fractons and so on to invistigate the possibilities and limitations of the eddy current separator. The result was that there existed few possibilities to extend the use of eddy current separators to more difficult separation

Ørbog, Arne (Danielsen, Svein W.)

Optimal production and use of crushed sand as concrete aggregate. Franzefoss Bruk AS in Trondheim produce a considerable quantity of crushed rock at their facility at Vassfjell Pukkverk. This thesis proposes that the product‟s characteristics can be modified in order to optimise it‟s performance in concrete and allow it‟s full employment for this purpose. A primary goal for the work underlying this thesis is to demonstrate that crushed rock can be used in larger quantities than at present if the contant of the filler and the type and quality of superplasticiser (SP) is optimised. The filler used here has been characterised by specific surface area and particle size distribution. Experimental work has been based upon a formulation for a C35 NA concrete with a w/c (water/cement ratio) of 0.6. A matrix formula has been used to select the most effective SP-product from 5 different commercially available materials. The matrix‟ flow resistance was measured with a FlowCyl-meter. The composition used in the matrix formulations was made up of the aggregate‟s content and particles < 0,125 mm, cement, water and additives. Filler separated from the crushed rock was used in 9 different formulations and used at the rate of 8, 12 and 20% on crushed rock. Filler was divided into two fractions, one consisting of particles below 75 µm and one consisting of particles from 75 to 125 µm. Each was tested in both matrix and concrete formaltions. The FlowCyl trials showed that flowability decreased with increasubg fukker cibtebt abd particularly with increasing content of the filler fraction consisting of particles < 75 µm. Pouring properties were found to depend more upon the particle size of the filler than it‟s content. The < 75 µm fraction was found to be particularly deleterious in this respect, especially when it constituted 100% of the filler fraction added.

Aase, Marianne (B. Brattli / NGU)

Groundwater investigations at Svean, Klæbu municipality with an emphasis on groundwater recharge and chemistry. The groundwater balance for a river plane near the Nidelven, Klæbu kommune, has been calculated using traditional methods and a geochemical modelling program called NETPATH. It is concluded that the river Nidelven contribute with 72.6% (78.4% using PC-modelling) to the groundwater recharge in the deposit, precipitation with 7.6% (7.6% using PC- modelling) and the area around with about 20% (14% using PC-modelling). The aquifer parameters (capacity, hydraulic conductivity, transmissivity and storage) are calculated from short and long time pumping tests. The water chemistry is evaluated and related to weathering processes in the unsaturated and saturated zone and the water chemistry of the Nidelven. It is concluded that the water quality is good and that natural processes in the soil remove potential contaminants from the river.

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1995

Arnesen, Linn A. (S. Lippard / N.Hydro)

Factors influencing on hydrocarbon columns. (Study area: the eastern flank of the Northern Viking Graben). The dimensions of the hydrocarbon columns are determined by the supply of hydrocarbons, the trap size, the seal capacity and the correct timing of events. Supply and timing are assumed to be successful in the northern Viking Graben. Hydrocarbon columns controlled by spillpoints are easily detected by the coinciding depth of the hydrocarbon-water contact and the spillpoint. This means that the main focus is laid on seal capacity and the influence of overpressure. Distribution of overpressure in the main reservoir, the Brent Group, is controlled by the distribution of low permeable seals and the drainage patterns of communicating carrier beds. The difference between the pore pressure and the minimum principal stress, the retention capacity, is analysed quantitatively for each hydrocarbon-bearing structure. It is found that fields with moderate to high overpressures seem to be controlled by seal capacity and seal failure, while the majority of the normally pressured fields are spillpoint controlled.

Aronsen, Hanne (K.L. Sandvik)

Nitrate added to organic household waste - Its effect on the composting process. Use of nitrates will inhibit the formation of smelling sulphur componds during the breakdown of food and garden waste. The work was carried out to evaluate the effect of nitrate addition to see how it positively could affect the storing of such garbage at the households.

Aune, Jorunn A. (S.O. Johnsen / N. Hydro)

Mapping of the Cretaceous sequence and a geological/geophysical evaluation of the Blodøks sand in block 25/7, west of Utsirahøgda. Due to rifting, uplift and erosion in the Mesozoic the Cretaceous sediments on parts of the Utsira High are deposited directly onto pre-Mesozoic sediments. Time and depth maps for five interpreted reflectors have been generated. The maps show that the Lower Cretaceous is deposited in several small basins, separated by highs, while the Upper Cretaceous is deposited in a more continous basin area. In the southern parts of block 25/7 the slope from the basinal areas up to the Utsira High is more gradual than in the central parts of the block. The gradient again decreases further north

Brantjes, J. (E. Roaldset / K. Weber / ERASMUS Delft Techn. Univ.

A study of the porosity - permeability relationships of different lithofacies in the Ness Formation, Oseberg Area, on the basis of logs and rock samples. The petrophysical properties as obtained from logs are studied and related to detailed description of sedimentary facies, sediment texture, mineralogy and physical properties measured in the laboratory.

Berg, Grete E. (S.O. Johnsen / PGS Nopec)

Evaluation of the hydrocarbon potential in block 127, 128 & 129 offshore Vietnam. Seismic interpretation has been carried out on the VOR-93 data, covering blocks 127, 128, and 129 offshore Vietnam. Four Tertiary horizons have been interpreted and mapped throughout the entire study area. One prospect has been mapped in detail and converted into depth values. Three possible traps within the prospect are identified as fractured and weathered basement, Ologicene sandstones and Miocene carbonates. Oligocene lacustrine shales are possible source rocks for all the three play types. The estimated hydrocarbon reserves are significant. The presence of hydrocarbons in the prospects are dependent of the quality of the lacustrine source rocks, which is regarded as the main risk. The method used for estimating the potential hydrocarbon reserves is regarded uncertain, due to the open seismic grid and lack of well data in the study area. 2D innfill seismic in-between the VOR-93 and VRP-93 data is suggested as further exploration of the study area.

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Bjørnå, Ragnhild (K.L. Sandvik / Reslab AS)

Experimental and Model Approach to Predict Effects of Produced Water Reinjection.

A follow up of the thesis carried out by Marianne Aam Ness in 1994.

Bjaanes, E.Ø. (E. Roaldset / Saga)

Mechanical properties of shales in relation to their mineralogical and chemical composition. The aim of the thesis was to outline a possible relationship between the mechanical properties of shales to their content of organic material and mineralogy. The mechanical strength of shales is of prime importance for their sealing efficiency and their stability with respect to drilling. High contents of smectite and/or organic matter are beneficial for sealing properties while unfavourable with respect to borehole stability. Higher contents of illite, kaolinite and carbonate cement increase the brittleness, and thereby reduce sealing capacity of shales.

Borgerud, Line K. (A. Myrvang)

Relation between rock stress and pore pressure on the Norwegian margin. A Study based on borehole breakouts. The studies of borehole breakouts showed that the interpretations were difficult. However, a WNW-ESE trend was revealed.

Brostrøm, Christian (S.O. Johnsen / Statoil)

Stochastic Modelling of Bounding Surfaces in Upper Raude Reservoir, Statfjord Field . The geometries of three (high frequency) sequence boundaries in eight wells have been modelled by using the stochastic modelling program “Sequence. Input to the program includes well interpretations and apriori distributions for the dimensions and geometry of incised valleys within the sequence boundaries. The stochastic model was able to generate realistic sequence boundary geometries and the results of multiple stochastic simulations have the potential to provide a better basis for reservoir management than conventional countour maps of zonal thicknesses. The main problems associated with applying “Sequence” are related to the input data: Where a thin sandstone occurs above a sequence boundary, it is often difficult to interpret whether the sandbody was deposited on an interfluvial surface or in an incised valley. There are little analogue data available to assist the estimation of apriori distributions for dimensions and geometry of the incised valleys. In addition a number of minor “bugs” and technical problems have been identified, and it is expected that these will be corrected befor the next release of the program.

Christensen, Hanne E. (B. Brattli / NGU)

Evaluation of the contents of lead in sediments from Skagerak. In this work the candidate examines how lead (Pb) appear in the Skagerak sediments. The amount of lead deposited in the sediments during the last 10, 20, 30, 40, 50, 100, 200 and 300 years is estimated. The contribution of antropogenic lead is evaluated.

Grimstad, S. (E. Roaldset)

Illitization of smectite as a function of depth: A case study of the Lower Tertiary Brygge Fm. Based on mineralogical and chemical analysis, and burial- and thermal-history modelling. Clay minerals amounts to more than 50 % of the bulk fraction with illite being the most and kaolinite the second most important clay mineral. Considering the clay fraction smectite is overall the most abundant mineral. Burial and thermal history modelling is performed on all wells to reveal the thermal conditions prevailing for the selected interval. The mineralogy observed from X-ray diffraction analyses combined with the modelled temperature conditions suggest that at these depths (down to 2000 m b.s.b.) the temperatures have either been too low, or the time too short, for prominent smectite to illite diagenesis.

111 Institutt for geologi og bergteknikk Hovedoppgaver 1995

Gule, Oddbjørn (A. Myrvang)

Numerical modelling of rock support at the Rommeriksporten tunnel.

Based upon field mapping and laboratory data, the performance of different rock bolt patterns was modelled, using the UDEC numerical code.

Hana, Kjetil (K. Rokoengen)

The development of Nidelva at Kjøpmannsgata. During excavations during the summer 1995 two soil profiles were exposed in an area of assumed early settlement in the Trondheim city area. The combination of Quaternary geology and archeology intended to throw light on the early city development and heavy metal contamination in the area.

Hegdahl, Trine Jahr (K.L. Sandvik)

Waste Disposal at Svalbard - A Ground Analysis of the Recharge Area at the Waste disposal Site in Svea. Sampling was undertaken downstream to a waste disposal heap at Svalbard to evaluate the seepage of pollution from the dumping area. This was done as start of a project by SINTEF to assess the general pollution potential of existing garbage dumps.

Hudson, Wellington (S.O. Johnsen / NORAD)

Sequence stratigraphic studies of the Paleocene in the Balder area, Central Viking Graben. The study is based on well data and seismic data. Interpretation of the log patterns suggests that several local small scale marine flooding surfaces and parasequences exist in the area. The local marine flooding surfaces and parasequences may have been formed in response to eustatic sea level changes and local tectonic activities. The sediments in the study area have been recognized to be deposited in a lowstand systemstract basin floor fan. The basin floor fans are formed in a type I sequence. Two categories of sedimentary strata exist; those which are continous, and those which are mounded and discontinous. Hemipelagic sedimentation is the most likely process that has led to the deposistion of the continous strata. On the other hand turbiditic transport and deposistion is the most likely process that has led to the deposistion of the discontinous mounded bodies. The main source of the sediments is likely to be the East Shetland Platform and the secondary source the Utsira High

Haavik, Torgeir (T. Malvik)

Beneficiation of calcite. Different testing methods in order to beneficiate carbonate rocks have been tried out. The work includes gravitative methods such as the Mozley Laboratory Separator and the Kelsey Jig to remove the sulphides and flotation as a cleaning step. The work also comprised microscopic studies to determine liberation properties of the minerals as a function of fineness of grind.

Johansen, Randi S. (S. Lippard / NGU)

Combined interpretation of the Vega High, from Aeromagnetic, Gravimetri and Seismic Data. Interpretation of gravity and magnetic data based on seismic interpretations and petrophysical measurements show no indication of a basement high below the Vega High, but it is found that depth to basement shallows under the Ylvingen Fault Zone. The anomalies are interpreted to indicate that the basement topography may have guided later faulting and by implication the location of the Vega High.

Jørgensen, Line G. (S.O. Johnsen / BP)

Troll Field Jurassic Correlation. A sequence stratigraphic correlation within a chronostratigraphic interval mainly covering the Sognefjord Formation and the Heather “B” Formation of wells in the Troll Field has been performed. The main goal was to see if it was possible to identify and characterize an erosinal surface that is observed north of the 62. paralell within the Upper Jurassic succession.

112 Institutt for geologi og bergteknikk Hovedoppgaver 1995

Well data as logs, biostratigraphic reports and core descriptions were used to identify genetic stratigraphic sequences within each well, followed by correlation over the entire area. Based on the correlation a sequence stratigraphic model has been constructed. The model describes six third order genetic stratigraphic sequences, interpreted to be deposited during forced regression of lowstand wedges. They prograde from east towards west. The model corresponds to a previously described model for the Troll Field and strengthens the validity of this model. The formation of the genetic stratigraphic sequences is linked to eustasy and tectonic activity. A clear erosional surface corresponding to the one observed further to the north is not observed on the Troll field. However, several minor erosinal surfaces corresponding to sequence boundaries formed during forced regressions are observed. One of these surfaces may be the corresponding one, showing that it is not as pronounced in this area as further north. A possible hiatus may exist between the biozones PJ31 and PJ27 in the easternmost part of the area. The hiatus is interpreted to represent non-deposition.

Karlsaune, Petter A. (K.L. Sandvik / T.heim kommune)

Reproducibility of geochemical Data from contaminated Soil. An evaluation of the amount of pollution at a location of contaminated soil using mineral assesing methods.

Kyrkjebø, Rune (S.O. Johnsen / IKU)

Depositional simulation of Cenozoic Sequence Stratigraphy in the Northern North Sea. The program DEMOSTRAT has been used to simulate Cenozoic depositional history. DEMOSTRAT is a forward process-based simulation program of the dynamic slope type, and has a depth-dependent dual-lithology diffusion equation which handles transport, erosion, and deposition of sediments.

Data used in the simulation are extracted from a seismic line in the Northern North sea (60N, east - west running, from the Øygarden Fault Zone to the East Shetland Platform), and from literature studies concerning the Northern North Sea. The most important of these parameter values are: Sea-level curve, tectonic subsidence, initial basin form, sediment supplies, isostasy parametres and compaction of sediemnets. The interaction between these parameter values could not reproduce a cross section similar to the observed cross section from seismic. Therefore, a reconsideration of the subsidence pattern and the initial basin form was done. This gave an anomalous Cenozoic subsidence pattern, different from the expected post-rift thermal subsidence. The deviation is previously described, but to the authors knowledge, the late Miocene - Pliocene anomalous subsidence has not before been described in the literature.

Lægreid, Ulf (S.O. Johnsen / Statoil)

Building a 3-D model of Channel Geometries in the Escanilla Formation, Spanish Pyrenees. A stochastic surface oriented modelling tool has been used in building an approximately deterministic three dimensional model of the Upper Olson Member in the Escanilla Formation, Spanish Pyrenees. Taking into account that actual field data has been used it is not known that a similar model has been built before. By using analogue field data provided from the SAFARI data base, a simple plan morphological interpretation of various channel belts has been constructed. Channel belts have been correlated between different outcrops. From these interpretations geometrical parameters such as channel belt directions, width and sinuosity has been observed or estimated depending on the degree of uncertainty incorporated within the parameter. From the 2D outcrops in the SAFARI data base additional parameters such as thickness, deepest point and the cross-sectional form have been estimated and measured. In conditioning the surface simulations fictious wells are used to define the areal extent of the observed channel belt sand bodies. This large set of data points for each channel belt provides the basis for defining model and observation files used in stochastic surface simulations. Surfaces defining the base and top of the different channel belts have been utilized in building the three dimensional model. The three dimensional model has an areal extent of 1.3 by 2.2 kilometres while the thickness is 110 meters. The model is thereby large enough to describe major reservoir heterogeneities within a well spacing characteristc of the hydrocarbon reservoirs in the Norwegian sector of the North Sea. The geological complexity of the fluvial environment is reflected in the model indicating that the surface oriented modelling tools are in fact quite powerful.

Mathillas, Frank Rune (K.L. Sandvik / T.heim Energiverk)

Environmental analysis of fly-ash from municipal waste incineration. Trondheim has a garbage incineration plant equipped with gas cleaning systems. The dust disposal was investigated.

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Moen, Stig (K.L. Sandvik / Miljølab AS)

Use of mineral fines to sink and flocculate oil.

Various agents have been tried out to disperse or get oil spilled on the sea to sink. Many of them are considered to be unsafe to use, and most of them are not allowed to be used in the Norwegian part of the North sea. Alternatives are therefore sought. In this work a number of ground natural minerals were tried out for this purpose. There is a good possibility that tis may work, but it could not be proved as the test setup still has to be improved.

Moxnes, M.A. (R. Sinding-Larsen)

Review of the hydrocarbon potential in Quadrants 35 & 36 within the Måløy fault block and the Uer Terrase using the resource assessment Shell software GeoX. This thesis has described the method of play analysis and executed analyses of the lower and upper Cretaceous basin in the North Viking Graben and the Southern Norwegian Sea, between 60-64°N and 2-7°E on the Norwegian shelf. The play analysis method havebeen used to estimate the potential of hydrocarbons in the area, particularly within quadrant 35 og 36 in the Måløy fault blocks and Uer Terrace. The GeoX play analysis software from Geoknowledge A/S has been used and proved to be a powerful and efficient tool for estimating hydrocarbon potential within the play area. The most critical points outlined by the thesis are the consistency and realism of the subjective judgement of probabilities and on the input of geological parameters. Several biases have been discussed which will lead to over- and under-estimation of the hydrocarbon potential. The lower Cretaceous turbidite play have a large upside potential for oil and gas, but even so less than for the lower Cretaceous debree flow play. However the largest accumulations in the turbidite play may contain substantially more hydrocarbons in plays than the debree flow play. The upper Cretaceous play has relatively small accumulations with greater risk than the lower Cretaceous play due to reservoir properties and seal integrety.

Musum, Rune (E. Roaldset / Amerada Hess)

Palaeozoic play models on the East Finnmark Platform ( 25°-30° E / 71°-72°30’N), with emphasis on reservoir rocks. The Palaeozoic succession of the East Finnmark Platform is studied and four play models classified on the basis of their reservoir rocks are defined and evaluated. The exploration wells are correlated, and major sequences providing a framework for the evaluation of the East Finnmark Platform is defined. 2D and 3D seismic data are interpreted, and give an insight of the general sediment distribution of the platform. Studies regarding salt movement and mounded features seen on the seismic data are also performed.

Nicolaysen, T. (R. Sinding-Larsen)

Description and evaluation of the resources within potential play models on the Finnmark platform. This thesis has evaluated the play potential on the Finnmark platform and estimated both volumetric attributes and risk factors connected with the plays. The risk factors and volumetric attributes have been justified based upon published information and calibrated against the resource assessment of the Barents Sea published by the Norwegian Petroleum Directorate. Play Analysis methodology has proved to be an excellent tool for synthesizing exploration results relative to the assessment of the resource potential on this platform.

Parida, Sanjay Kumar (B. Nilsen / NORAD / NTE)

Evaluation of Unlined High Pressure Tunnels. Ormsetfoss Hydroelectric Project, Norway. A Case study. Following a thorough review of the engineering geological conditions, the design of the unlined pressure shaft at Ormsetfoss are analysed based on 1) Empirical methods (literature review), 2) Rules of thumb (modified equilibrium methods) and 3) Numerical modelling. It is concluded that according to all analyses carried out, the design of the pressure shaft is well on the safe side.

Pradhan, Pratik (E. Broch / NORAD)

Prediction of rock support in Melamchi tunnel, Nepal. The Melamchi Project is a water supply project to the Kathmandu valley in Nepal. The proposed tunnel for the project is about 26 km long and 2.5 m in diameter and is to convey 8 m3/s. The objective of the study is to characterize the rock mass and to predict the amount of rock support required at the pre-construction stage by the application of the two most commonly used classification systems, the Q-system and Rock Mass Rating method. The principal design philosophy to

114 Institutt for geologi og bergteknikk Hovedoppgaver 1995 achieve a self supporting rock mass with minimum support has been used. The support prediction by the Q-system requires less support than those predicted by RMR.

Ramberg, Jørn (S. Lippard / Statoil)

Seismic 3-D interpretation and prospect evaluation of the pre-Cretaceous in the western part of Block 34/6. Block 34/6 is located in the northeastern part of the Tampen Spur in the northern North Sea. The Visund Fault, which forms the boundary between the Tampen Spur and the Viking Graben in the block, has a NE-SW trend. To the west and south there are westerly rotated fault blocks, while to the north and east there are easterly rotated fault blocks, giving rise to a graben structure between. Evualation of Prospect A in the southern part of the block gives 3.01 Sm3 for the intra Dunlin reservoir and 4.24 Sm3 for the Statfjord reservoir.

Ratnayake, Prasanna (E. Broch / Lu Ming / NORAD)

Design of high pressure tunnels. The report summarizes the available design methods namely, use of Empirical methods, Finite Element charts and the use of Numerical modelling to examine their validity at different topographical and geological terrains. There are various empirical methods or “rule of thumb methods” in use like the vertical criterion for confinement, Snowy Mountain Criterion for Confinement and the Norwegian criterion for confinement. Two dimensional finite element charts prepared at NTH and use of three dimensional Finite Element methods are the other two methods selected. For the calculation of safety the minimum principal stress was compared with the maximum water pressure at critical locations of the pressure shafts. The Numerical model used was COSHWA3 Finite Element model, developed at SINTEF, Trondheim.

Sandøy, Roar (R. Sinding-Larsen)

A description of the mineralogical and geochemical alteration from gabbro to scapolitized rock (Ødegårditt) from Ødegaarden in Bamble, Telemark.

Drill cores from Ødegaardens Verk has been described mineralogically and geochemically and evaluated against changes in density and magnetic susceptibility. This evaluation led to the subdivision of the material into seven lithological zones and a subdivision of two of these zones. The different zones have been interpreted to represent the initial clinopyroxene-rich rocks in the area as well as the different stages in a metamorphic transformation and a process of scapolitization. The clinopyroxene rich rock type was evaluated regarding changes in density during metamorphoses and scapolitization. In addition the error committed if the assumption about initial rock types for the scapolitization is wrong has been evaluated. The earlier indicated negative correlation between rutil and magnetic susceptibility was confirmed and this leads to greater confidence in the ore reserve estimation which have been done on the basis on magnetic field measurements. The thesis also contains a short review of economically valuable minerals from earlier mining attempt as well as potentially economic minerals for the future contained in the Ødegaarden Verk deposit.

Schefte, Geir (K.L. Sandvik / RWTH Aachen)

Physical and chemical factors affecting the separation of a synthetic mixture of polypropylene and polyethylene.after triboelectric charging in an electic field. This work was carried out in RWTH Aachen as part of the Erasmus student exchange progaramme. The student took part in a project where the aim was to recirculate plastic. To do that the different types of plastic has to be separated from each other. In this work artificial mixtures of polypropylene and polyethylene were separated bu triboelctric methods after pretreatment with a dye to give the to components a different surface charge.

Schönborn, Thomas (Nilsen / Myrvang, in cooperation with RWTH Aachen & A/S Olivin)

Stability analysis of the Gausdal open pit mine. A stability analysis for the Gausdal open pit peridotite mine in Western Norway has been carried out. Based on comprehensive joint mapping, three main joint sets were identified. The most distinct is represented by steep foliation joints, striking parallell to the main slope. The main risk of slope failure is represented by undercutting of these foliation joints. The factor of safety may be increased by as much 40 % by draining the slope.

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Skjel, Marit (T. Myran)

Quartz dust. Health and environmental aspects related to road dust and traffic pollution.

Rock containing up to 70% quartz are used in road pavement in Norway. Use of studded tires produce high concentration of air-borne dust because of the wear and tear of the pavement. This work discuss the health and environmental aspects concerning the quartz content in the air-borne dust, and if the quartz content in the road dust should be evaluated as being more important than earlier believed.

Skaaden, Nina Røe (K.L. Sandvik)

Recycling of small electronic devices. The amount of electronic equipment ending as waste is increasing rapidly. In this work small eloctronic devices like radios were considered. Standard dry mineral processing methods were employed to separate the devices into useful raw materials such as plastic, metal , iron, precious metals and so on.

Solheim, T.C. (R. Sinding-Larsen / Elf)

A study of the relationship between the parameters which control the development of faults as well as joints and actualistic tectonic situations described in the literature or internal reports. The thesis has quantified the parameters which quantifies faulting. The mechanics of faulting and the basic relationship between faults on a local scale in relation to regional stress have been discussed. An extensive literatury survey has been conducted outlining the major theories which have been proposed for the characterisation of faults.

Storkjørren, Arild (K.L. Sandvik / Miljø og Anlegg AS / Norsk Kjøleindustri AS)

Removal of freon and recirculating of material form refrigating units. Refrigation units end finally as waste. Most such units ending as waste today cause environmental problems unless handled to remove the freon contained in a safe way. The work is a survey of the methods that can be utilized to recycle refrigating units.

Svare, Eirik Inge (S.O. Johnsen / N. Hydro)

Relations between Rock Stresses and Pore Pressure on the Norwegian Margin, 62 to 67 north - A study based on leak-off Tests and formation Pressure. Minimum principal stresses are estimated from leak-off tests, primarily by reading of the shut-in pressure. In the northwestern parts of the Halten terrace, relatively great variastions in S3 are observed within geographically small areas. A close relation between pore pressure and minimum stress is revealed, showing considerable increase in stress in the highly overpressures formations. A stress diffrence of 100 bars is found between the hydrostatic- and highly overpressured Jurassic at 4000 meters. The vertical stresses (Sv) are derived from integration of density-logs. The Mid-Norwegian shelf is overconsolidated with an average density about 100 meters below the sea-bed of 2,1 g/cm3. Average Sv profiles are computed within geographically and structurally defined areas with small internal variations. The Sv profiles within each area show relatively small differences, less than 30 bars, but these differences can be related mainly to differences in water-depths and formation pressures. Regional comparison of the stresses shows that the minimum principal stress is horizontal (Sh=S3) and regionally Sh equals about 90% of the vertical stress. The stress regime is most likely strike-slip faulting, but an almost isotropic extesional regime cannot be ruled out. Within the highly overpressured zones, Sh is appraching Sv. Sh/Sv ratios of 0,98 are found in the highest pressured Middle Jurassic reservoirs in the western part of the Halten Terrace. The retention capacity (Rc) is calculated in dry wells in the Middle Jurassic garn Formation. These calculations show that all hydrocarbon discoveries were made in reservoirs with Rc greater than 200 bars. The smallest capacities of 100 bars are recorded in the highly overpressured wells, and hydrolic fracturing today seems improbable. Rapid burial during Pliocene and Pleistocene enables pressure increase caused by increased overburden and accelerate the thermal effect. This process was likely one main overpressure contributor. Differential rapid burial, with higher rate of subsidence to the west, can explain the higher overpressures in the Cretaceous and Jurassic rocks in this area.

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However, undercompaction caused by rapid loading cannot be related to the highest overpressures, 85% of Sv, found in some wells west on the Halten Terrace.

Sæter, Toril (E. Roaldset)

Reservoir properties in Pre-Jurassic deposits, Eastern Barents Sea. In an area from 20° -29° E and from 71°-74° N the regional distribution of Upper Palaeozoic carbonate deposits are studied by means of well log data and detailed investigations of drill bit cuttings (thin section petrography, X-ray diffractometry, etc. The carbonates are influenced by secondary porosity due to post depositional flushing of meteoric water, but later silicification has reduced the porosity). Organic matter analyses suggest Triassic shales to moderate source potential.

Sørhaug, Trond (S. Lippard / Statoil)

Synthesis of the post-Caledonian tectonic evolution in East Greenland (69-76°N). The Caledonian orogeny in East Greenland ended with deep Devonian-Carboniferous basins formed by post-orogenic collapse. Extensive block faulting at the transition to the Permian resulted in rift margin uplift and peneplanation. A renewed stage of block faulting occurred in the mid-Permian before being replaced by thermal subsidence during the remainder of the Permian and Triassic. Renewed rifting started in the mid-late Jurassic. Rifting started in the south and propagated northwards. The two major rift basins had different tectonic styles. Regular subsidence with little fault deformation dominated the southern Jameson Land basin. In contrast, the northern Wollaston Foreland basin experienced active faulting and block rotation until the early Cretaceous. Thermal subsidence, interupted only by minor faulting along the marginal faults, lasted throughout the Cretaceous. Successful sea-floor spreading commenced in the Paleocene with the extrusion of plateau basalts.

Taheri, Ashkan (K.L. Sandvik / TU Delft)

Dust Explosion Testing at elevated initial Pressure. This work was carried out in Delft when Taheri was an Erasmus exchange student under the guidance of Dr Lemkowitz. Using equipment developed there. WE do not carry out research in this area.

Ulvang, Roy (T. Myran)

Dust and sand escape from the mud depot at the Storwartz mine area. The mud depot is characterized by mineralogical chemical analysis. Measurements of the air-borne dust concentration is done, and the results related to meteorological and other specific parameters for the Storwartz mine area. The health risk for persons which are exposed for the air-borne dust is evaluated.

Våg, Berit (S.O. Johnsen / N. Hydro)

Depositional environment, paleogeography and sequence stratigraphy of the Brent Group, block 34/8, northern North Sea. The thesis is confidential, abstract not available.

Øverland, Jan Håvard (B. Nilsen / NSB Baneregion Nord)

Railway tunnels in Trøndelag - Engineering geological analysis of portal areas. Engineering geological mapping and stability evaluation of about 30 portal areas of railway tunnels in Trøndelag have been carried out. The need of rock support has been discussed, and technical solutions evaluated. Only in two cases, potential instability has been identified. For these cases, a system for continuous monitoring is suggested.

Åm, Mari (R. Sinding-Larsen / Norsk Hydro)

An evaluation of the most important biases in risk analyses at the play and prospect level in relation to alternative geological models and factual observations. The thesis has performed a post mortem on seven prospects with on the average three alternative prospect models for each prospect. The results show that the different trap and reservoir parameters exhibit large differences between the actual values and the ones estimated prior to drilling. Porosity seems to be the most difficult to predict without bias. The

117 Institutt for geologi og bergteknikk Hovedoppgaver 1995 thesis discusses the risking procedure performed by Norsk Hydro in relation to other approaches used in the industry and outlines the major differences.

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1994

Andama, Godfrey (S.O. Johnsen / NORAD)

A Seismic Stratigraphic study of the Cretaceous and Tertiary Sections in Blocks 31/1,2,3,4,5, and 6, and 32/1 and 4 in the Norwegian sector of the North Sea. Lithologic and chronostratigraphic data together with data from velocity logs from 7 wells have been used to calibrate the seismic profiles. Using the principles of seismic stratigraphy one major time stratigraphic unit was identified in the Cretaceous and six other in the Tertiary of the study area. The Cretaceous sequence is composed of limestone and marls of the Cromer Knoll Group and the overlying claystones of the Shetland Group. On dip sections the sequences pinches downdip against the late Cretaceous unconformity in the east, and in the west it pinches updip against what appears to be a shelf break. The reflection configuration consists of parallel continuous reflections of moderate to high amplitudes indicating that sediments of this sequence were deposited by low velocity processes in a deep marine/marginal marine environment. The Tertiary sequences consists mostly of claystones, occasionally with stringers of limestone, sandstone, and marl. The sequences were deposited in a deep to marginal marine environment by various sedimentary processes of mass flow, slump, and turbidity flow. Stratigraphic development of the Tertiary setting was controlled by the episodic tectonic events that occurred throughout the period, global sea-level changes and subsidence of the North Sea Basin and the margin.

Byaktuaga, Andrew K. (S.O. Johnsen / NORAD)

A Seismic Stratigraphic Study of the Cretaceous and Tertiary Sections in Blocks 31/7,8,9,10,11, and 12, and 32/7 and 10 in the Norwegian Sector of the North Sea. Seismic stratigraphic interpretation of seismic data provides a means of determining depositional history, depositional environment, structural evolution and delineating depositional and lithologic boundaries. In this thesis work the use of seismic stratigraphy in correlation with well data resulted in a clear understanding of the geologic and stratigraphic history of the area. The area underwent subsidence during the Cretaceous due to reactivation of of the Jurassic faults, and resulted in the rise of sealevel, providing a deep environment of deposition. The sediments deposited in this period were mainly marls and carbonaceous mudstones. During the Tertiary a series of uplifts influenced deposition, creating wedge shaped forms of sediments and prograding clinoforms. Most of the sediments originated mainly from the east, the Fennoscandian landmass and few from the west, the East Shetland Platform. Towards the close of Tertiary, movements along the Øygarden fault Zone and the fall in sealevel resulted in the deposition of sandbodies north-east of the area. The low burial depth of potential source rocks and lack of sealing faults in the sandstones, greatly reduces the petroleum prospectivity of this area.

Broch, Hanna Rachel (B. Nilsen / St.Vegvesen / Anleggskontoret)

Optimisation of alignment of Drøbak sub-sea tunnel.

A key issue in the planning of sub-sea tunnels is to optimise the alignment according to the actual engineering geological conditions. This thesis particularly emphasises on engineering geological optimisation regarding rock cover. The effect of increase/reduction of rock cover on cost is also discussed. Based on engineering geological evaluation it is concluded that in this case 30 m rock cover is satisfactory.

Frost, Thomas H. (K.L. Sandvik / NOAH A/S)

Process analysis of the acid neutralization plant of NOAH A/S, Langøya. This is an investigation of the plant for neutralizing and solidifying inorganic wastes.at Langøya. Emphasis is put on the economic use of limestone and lime.

Gabrielsen, P.T. (S. Lippard / BP)

Syn-rift stratigraphic geometries in Blocks 7219/9 and 7220/7. Late Jurassic-early Cretaceous syn-rift sequences in the southern part of the Bjørnøya basin were investigated using seismic sequence stratigraphy. The syn-rift megasequence is divided into 5 sequences representing 3 rifting events.

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Each rifting event is characterised by downslip and rotation of the hangingwall block and uplift and erosion of the footwall block. Mass gravity flows are interpreted to be associated with the initiation of each rifting event, seen as sequences with wedge-shape and prograding and mounded internal geometry. After each rifting event, smaller amounts of sediment were transported into the basin and thin sheet-like draping sequences with parallel internal reflections showing onlap formed.

Grøntveit, Jorunn (E. Broch)

The decision making process for selection of tunnel support. Different models for decision making are described and comparison with selection procedures for rock support in Norwegian tunnels are discussed. An enquiry among a group of rock engineers shows that a number of factors in addition to the geotechnical situation may have an influence on the final decision. Risk analysis and decision system for the crossing of a major fault zone (Bryn) in the Romeriksporten railway tunnel is described.

Helland, June (R. Sinding-Larsen)

Description of known and potential plays from the Cretaceous of the Barents Sea. This thesis estimates the hydrocarbon resources of the Cretaceous in the North Viking Graben and Southern Norwegian Sea. This was done by using the software program GeoX from Geoknowledge A/S and the method of play analysis. Play analysis parameter values and variables necessary to estimate the resource potential were described explicitly. Both the upper and lower Cretaceous plays were analysed. The results of this thesis show that play analysis is an effective and powerful tool for assessing the hydrocarbon resources within plays. However, it became clear that the assessor must be consistent and careful in the selection of realistic input parameters. Play analysis also allows one to address risk at both the play and prospect scale and allows the presentation of both the volumetric input variables as well as the result with ranges of uncertainties. Nevertheless, the problem associated with the play analysis is to know how to use subjective judgements consistently and calibrate their meaning in terms of probabilities and probability distributions.

Johansen, A. Hjulstad (K. Nielsen)

A possibility study of underground mining of Blue Pearl labradorite. Labradorite is a highly priced dimension stone unique to Norway. Excavation is done by qyarrying, but underground mining could represent both economic and environmental advantages to the industry. The thesis presents a technical study of a potential underground operation. The design was based on careful development blasting and extensive use of diamond wire cutting technology. The primary excavation must be done with large blocks with volumes of several hundred m3, and will necessitate the opening of very large stopes. Rock mechanics evaluations including ground stability and feasible methods for ground support constituted an important part of the study.

Jørgensen, T. (A. Myrvang)

Determination and evaluation of in situ stress at the Snorre Field. (Danish exchange student) A stress study using well leak off tests were reasonably successful, indicating a NE-SW trend of the major, Khorizontal stress. However, further research was recommended.

Kvam, Asle (B. Brattli)

Groundwater supply to Kyrksæterøra and Vinjeøra in Hemne county. The candidate has evaluated the condition for groundwater supply to Kyrksæterøra from a large glacial delta near the Søa river and the lake Rovatnet v/Eidsneset. The aquifer parameters (capacity, hydraulic conductivity, transmissivity and storage) are calculated from short and long time pumping tests. The water chemistry is analysed and related to the water quality standard given by Folkehelsa. It is concluded that water from the lake Rovatnet is flowing into the ground water basin recharging the aquifer.

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Langhelle, J. (R. Sinding-Larsen)

Elaboration and analysis of a procedure for the systematic testing of freetext versus structured justification related to risk factors in play assessment. A Synthetic play was created using a South East Asian play as a model, but with additions and changes both to create a play that was unknown to all the participating explorationists and to create a documentation that was complete for the task at hand. Experienced explorationists estimated prospect level risk for the synthetic play using an intermixed schedule of freetext and structured justifications with free text justifications serving as a control for the evaluation of structured justifications. A subset of the GeoX justification functionality from the Geoknowledge company A/S was used in the experiment. The task did not consider the choice of justification approach nor the explicit documentation of data sources for an argument element. The play was unproven and the explorationists were provided with estimates of the major volumetric input parameters for analysis of play prospectivity. It is first important to note the exploratory nature of this thesis. The sample size was limited to six explorationists. The study involved a single, simple play analysis situation, but with limited time allocated to the development of justified risk estimates. The experiment tested a subset of the GeoX justification functionality and the test involved chauffeur driven interaction with a justification functionality. Having noted these limitations, the main results indicate that average argumentation performance is quite similar for freetext and structured justification. Freetext justification appears, however, to produce greater variance in both number of argument elements produced and time used. Further research is needed to replicate and refine these findings. The results also suggest that the experimental design provides an interesting research vehicle. In the final debriefing the participating explorationists felt that the justifications had captured the main elements of their thinking. Although the structured justifications were unfamiliar, the explorationists did not feel that they were less valid than their freetext justifications.

Langlo, Anne K. (E. Roaldset / Statoil)

The effects of sandstone heterogeneity on water flooding. Several techniques were applied to characterise sandstone hetereogenities with respect to sedimentary features, mineralogical composition and reservoir properties. Rock sections (slices) of reservoir analogues were water flooded and studied in a computer tomograph. The flooding was visualised by video techniques. Small scale sedimentary textures (cross bedding, lamination) appeared to have large impact on the flooding efficiency and the smoothness of the water front.

Moe, C. (S. Lippard / IKU)

Seismic interpretation of Cretaceous and Lower Tertiary on the southeast margin of the Møre Basin. The study area is part of the southeast margin of the Møre Basin bounded by the Møre-Trøndelag fault complex to the southeast and the Gossan High to the northwest. Base Cretaceous, Blodøks Formation, Base Tertiary and Top Paleocene are the dominant reflectors and divide the sequence into three intervals. The Cretaceous is dominated by marine shales but with interbedded sandstone and limestone intervals. Possible sand bodies are mapped with the help of amplitude anomalies. The sand has probably been deposited by submarine fans and fan deltas, the form of which were controlled by tectonics and sea level. The Lower Tertiary consists of shallow marine deposits. Analogies with areas to the south (Agat) and north (Nordland Ridge) show that the geological conditions were probably favourable for the deposition of Cretaceous sands in the form of submarine fans.

Ness, Marianne Aam (K.L. Sandvik / ResLab AS)

Produced Water Re-Injection (WPRI); Measurements and Characterisation of Water Quality. Testwork is undertaken to perdict the success of produced water reinjection into producing oil wells.

Olsen, T.Kollien (R. Sinding-Larsen)

Description of known and potential plays from the Tertiary of the Norwegian and Barents Sea.. The thesis consists of a literatury survey of the Tertiary on the Norwegian shelf and in the Barents Sea. Four play models have been described in the Barent Sea, two along the western margin, one between 74N and Svalbard and one in the Northcap basin. On the mid-Norwegian shelf three play models have been analysed, the Møre and Vørings sub basins as well as areas around the Nordlandsrygg and the Gossen Graben. The greatest uncertainty for the plays in

121 Institutt for geologi og bergteknikk Hovedoppgaver 1994 these areas is presence of reservoir sands. The large areas covered by these models result in a high upside potential even if the risk is substantial. The resource figures in this thesis should be regarded as very uncertain because the bases for the estimates are only published literature which do not contain the latest information from these areas.

Otteren, Ane (S.O. Johnsen / Statoil)

Seismic sequence stratigraphy of Tertiary sediments in the Møre Basin.

Three seismic sequences have been interpreted in an area streching from 6115‟ til 6245‟ N, covering the quadrants 34, 35, 6202, and 6203. The seismic interpretation of the sequences was correlated to wells by use of synthetic seismograms. The dating of the reflectors was done by connecting the seismic interpretations to completion logs from the wells. As the wells were drilled with Cretaceous and Jurassic sediments as targets, cores were not taken in the Tertiary intervall. The dating of the two youngest reflectors is therefore uncertain. The oldest sequence consists of a prograding unit of Paleocene sediments that may be deposited from landareas in the east. The overlying sequence consists of Eocene and Oligocene sediments. Also this sequence is probably deposited from the east. The youngest sequence is interpreted to consist of Miocene sediments and is only present in the basinal areas. The two oldest sequenses have been drilled. In the well areas the oldest sequence consists mainly of claystone, but sandbeds occur. The Eocene and Oligocene sediments are more sandy. Biostratigraphic studies shows that the sediments represented in the two oldest sequences are deposited on the outer shelf, slope, and deeper marine. The youngest sequence is not present in the well areas. On the seismics the sequens is represented by a hummocky faciespattern that may reflect sandy fan deposits. A sea-level analysis has been performed to get a better understanding of the deposits. Relative sealevel changes dominate over eustatic sealevel changes. This is due to the Tertiary uplift of the landmass in the east. The fans are probably deposited in a lowstand systemstract, probably as deep marine turbidites. The prospectivity of the sequence is uncertain. Top-seal may be a problem for the sediments younger than the Balder tuff.

Rørnes, A. (S. Lippard / Statoil)

Fault analysis of the Gullfaks Field, northern North Sea. The fault populations in the Gullfaks Field were studied to investigate throw distributions. The results show that the faults in the area are not fractal, but that several populations, distinguished by geometrical, genetic and geographical criteria, show power-law distributions. The seismic data were used to study throw variations along the faults, in order to study their formation mechanisms. Throw analysis show that the displacements along the major faults increase with depth from the Rannoch Formation to the Statfjord Formation. This is explained by a chage from simple faults at Statfjord level to a wider zone of deformation at Rannoch level. The study also suggests that fault activity took place in the late Triassic as well as the main extension phase in the late Jurassic.

Rørvik, B.K. (R. Sinding-Larsen)

Description of known and potential plays from the Cretaceous of the Norwegian and Barents Seas. This thesis has estimated the expected hydrocarbon resources on the mid-Norwegian shelf. The resources from four different play models have been analysed. A comparison between the estimates derived by the Norwegian Petroleum Directorate (NPD) and the estimates derived in the thesis show that the latter are significantly larger. This can mainly be attributed to over optimistic estimation of the marginal play probability as well as a too high expected density of prospects.

Semb, Eva Therese (K.L. Sandvik)

Environmental Performance Evaluation utilizing Environmental Indicators. A system for environmental performance evaluation was tested out on a ferroalloy plant.

Sivertsen, Svein-Arne (B. Nilsen / St. Vegvesen, Troms)

Durability of rock support in Maursund and Kvalsund sub-sea tunnels Because of the particularly aggressive environment of sub-sea tunnels, durability of rock support is a key issue. Visual inspection, sampling and laboratory testing of support elements, with main emphasis on rock bolts and shotcrete have been carried out. Indications of initial wash out of cement have been identified, but no corrosion of rock bolts.

122 Institutt for geologi og bergteknikk Hovedoppgaver 1994

Skjelle, Hilde (R. Sinding-Larsen / Statoil)

An evaluation based upon historical drilling results of play assumptions like constant future discovery probabilities and the probability of oil as well as expected accumulation sizes. This thesis has investigated drilling statistics in order to evaluate if there are significant changes in the success rate during the exploration of different plays. A statistical Beta distribution has been used as a prior and this distribution has been updated with drilling results in order to calculate a posterior distribution for the success rate as a function of progressing drilling results. Some significant changes were detected probably due to an initial heterogeneous play definition comprising sub-plays with different conditional probabilities for the discovery of petroleum. The experience and methodology derived during this thesis has laid the foundations for a more systematic evaluation of future success ratios on the Norwegian shelf.

Svare, Erik I. (S.O. Johnsen / N. Hydro)

Relations between rock stresses and pore pressure on the Norwegian margin, 62° to 67°N. A study based on leak-off tests and formation pressure. Minimum principal stresses are estimated from leak-off tests, primarily by reading of the shut-in pressure. In the northwestern parts of the Halten terrace, relatively great variations in S3 are observed within geographically small areas. A close relation between pore pressure and minimum stress is revealed, showing considerable increase in stress in the highly overpressures formations. A stress difference of 100 bars is found between the hydrostatic- and highly overpressured Jurassic at 4000 meters. The vertical stresses (Sv) are derived from integration of density-logs. The Mid-Norwegian shelf is overconsolidated with an average density about 100 meters below the sea-bed of 2,1 g/cm3. Average Sv profiles are computed within geographically and structurally defined areas with small internal variations. The Sv profiles within each area show relatively small differences, less than 30 bars, but these differences can be related mainly to differences in water-depths and formation pressures. Regional comparison of the stresses shows that the minimum principal stress is horizontal (Sh=S3) and regionally Sh equals about 90% of the vertical stress. The stress regime is most likely strike-slip faulting, but an almost isotropic extensional regime cannot be ruled out. Within the highly overpressured zones, Sh is appraching Sv. Sh/Sv ratios of 0,98 are found in the highest pressured Middle Jurassic reservoirs in the western part of the Halten Terrace. The retention capacity (Rc) is calculated in dry wells in the Middle Jurassic garn Formation. These calculations show that all hydrocarbon discoveries were made in reservoirs with Rc greater than 200 bars. The smallest capacities of 100 bars are recorded in the highly overpressured wells, and hydrolic fracturing today seems improbable. Rapid burial during Pliocene and Pleistocene enables pressure increase caused by increased overburden and accelerate the thermal effect. This process was likely one main overpressure contributor. Differential rapid burial, with higher rate of subsidence to the west, can explain the higher overpressures in the Cretaceous and Jurassic rocks in this area. However, undercompaction caused by rapid loading cannot be related to the highest overpressures, 85% of Sv, found in some wells west on the Halten Terrace.

Sveinsborg, Kari (K.L. Sandvik / Statoil)

Environmental Impact assesment (EIA) as an Active and Integtrrated Tool in Project Development Examplified for Transportation of Sleipner East Condensate. Environmental impact analysis is required afor larger physical projects in Norway. In this work the impact analysis was compared to what actually happened after th plant was put into use probably for the first time in Norway.

Svendsen, Svein-Erik (K.L. Sandvik / NSO)

Produksjon og bruk av knuste steinmaterialer i Franzefoss. Sampling of Waste Oil. Methods to sample waste oil were tested and compared to each other.

123 Institutt for geologi og bergteknikk Hovedoppgaver 1994

Telje, Gry (S.O. Johnsen / N. Hydro)

Paleocene sand development in block 35/11.

Geographical distribution and depositional mechanisms for Paleocene sands in block 35/11 has been evaluated based on an integrated interpretation of well logs, biostratigraphic reports and seismics. A depositional model for the whole Rogaland Group has also been established. The sediments are deposited inconformably onto the Cretaceous deposits. There is also a widely distributed internal inconformity at the base of the Lista Formation. The Lista sand is deposited within three different biostratigarphic zones. The sandbodies are clean and massive. Four seismic reflectors (Top Cretaceous, Base Lista Sand, Top Lista Sand, Top Balder) have been mapped. Sandbodies shows different reflection patterns. The largest sandanomalies show a pattern of channel erosion at the base and a hummocky pattern at the top. The sandbodies have a random distribution. A stacking velocity map has been generated in order to map sandbodies as velocity anomalies. During the deposition of the Rogaland Group a clastic system prograded from the east. Most of the transport occurred as turbidity currents.

Thiis, Thomas (K.L. Sandvik)

Spreading of emulsion under in situ burning. This project was carried out together with SINTEF at Spitsbergen. Oil was allowed to spread on the surface and then ignited. The purpose was to evaluate the effect of in situ burning as a tool of oil spill removal in arctic areas.

Tressum, Synnøve (S.O. Johnsen)

Models for submarine fan deposits within a sequence stratigraphic framework. The thesis is a literature study aiming at identifying the factors controlling the deposition of submarine fans and to put these factors into a sequence stratigraphic connection. During the last 20 years several different models have been proposed for the formation of submarine fans. These models deals with physiography, facies associations, and depositional relationships. Three of these models (Normark, Mutti & Ricci Lucchi, Walker) have been investigated. In addition, an attempt to classify the fans within a structural framework and a comparison of sand rich and clay rich fans has been performed. There seems to be a certain relationship between structural framework and the formation of sand- vs. shale-rich fans. Small sand-rich fans are formed along active margins and large shale-rich fans along passive margins. Both sequence stratigraphic theory and the different models for fanformation emphasizes the importance of lowstand. Present day fans are formed under highstand conditions. There seems to be three factors controlling this. Firstly the fans are connected to narrow shelves with rather steep slopes. Secondly, the canyons that often are connected to the fans, widens towards land where they are connected to a large river transporting material to the sea at the same time as the sealevel rises so that the river can carry the material directly to the deep sea. Thirdly, there must be a possibility for oversteepening of the shelf so that material can be transported downwards by gravity flows.

Trøan, L.I. (R. Sinding-Larsen)

Description of the known and potential plays from Tertiary in the North Sea. This thesis has evaluated three play from the Tertiary in the North Sea. The North Viking Graben play, a South Viking Graben play and Central Viking Graben play. The three different plays have large similarities and the South Viking Graben play has been used as an analogue for the North Viking Graben play. The total resources for all the plays in the Tertiary has been estimated to 510 million tons of oil equivalent T.O.E. conditional on the North Viking Graben play being confirmed. Comparing with the Petroleum Directorate‟s estimates it is seen that the ones derived by this thesis are more optimistic, probably due to a more optimistic evaluation of risk both at a play and prospect level.

Tyridal, D.S. (Aagaard,P. UiO / E.Roaldset, Cand.scient.)

Lithological and mineralogical composition of mudstones related to log response. The response of petrophysical logs in argillaceous sediments was correlated with variation in porosity, lithology and clay mineralogy. In smectitic claystones sonic and density logs are sensitive to changes in silt content. The mudstones can be treated as a three component system in the sonic density crossplot where the silt fraction, the clay fraction and the

124 Institutt for geologi og bergteknikk Hovedoppgaver 1994 porosity is representing the end points. The resistivity logs are mainly influenced by changes in porosity and not so much by changes in lithology. Surface conductivity seems to play a limited role in deeply buried claystone sections.

Vik, May Britt (R. Sinding-Larsen)

Elaboration and analysis of a procedure for the systematic testing of freetext versus structured justification related to risk factors in play assessment. A Synthetic play was created using a South East Asian play as a model, but with additions and changes both to create a play that was unknown to all the participating explorationists and to create a documentation that was complete for the task at hand. Experienced explorationists estimated prospect level risk for the synthetic play using an intermixed schedule of freetext and structured justifications with free text justifications serving as a control for the evaluation of structured justifications. A subset of the GeoX justification functionality from the Geoknowledge company A/S was used in the experiment. The task did not consider the choice of justification approach nor the explicit documentation of data sources for an argument element. The play was unproven and the explorationists were provided with estimates of the major volumetric input parameters for analysis of play prospectivity. It is first important to note the exploratory nature of this thesis. The sample size was limited to six explorationists. The study involved a single, simple play analysis situation, but with limited time allocated to the development of justified risk estimates. The experiment tested a subset of the GeoX justification functionality and the test involved chauffeur driven interaction with a justification functionality. Having noted these limitations, the main results indicate that average argumentation performance is quite similar for freetext and structured justification. Freetext justification appears, however, to produce greater variance in both number of argument elements produced and time used. Further research is needed to replicate and refine these findings. The results also suggest that the experimental design provides an interesting research vehicle. In the final debriefing the participating explorationists felt that the justifications had captured the main elements of their thinking. Although the structured justifications were unfamiliar, the explorationists did not feel that they were less valid than their freetext justifications.

Ødegaard, T. (R. Sinding-Larsen)

Play and hydrocarbon resource analysis of the Trøndelag Platform. This thesis estimates the hydrocarbon potential on the Trøndelag platform in the Norwegian Sea. Two study areas were chosen, the Frøya High, the Vega High. The Frøya High comprises a series of stratigraphic traps in Upper Jurassic/Lower Cretaceous shallow marine sand bars. The Vega High play is composed of structural traps in Middle Jurassic shallow marine to coastal deltaic sands. The Frøya High play was divided into two sub plays, because of two different hydrocarbon source areas. The Vega High play was divided into two scenarios. In scenario 1 the two seismicly well defined structures A and B on Vega High are divided into a number of prospects. Scenario 2 regards the structures A and B as too large prospects. However, the main consern for both scenarios is the source potential in the Helgeland basin. To estimate the resources in the plays, a program, GeoX/GeoPlay from the Geoknowledge A/S Company was used. This program estimate the play potential and the dry hole probability based on the input of volum parameters, existence parameters and reservoir parameters.

Aarset, Arnstein (E. Broch)

Engineering geological investigations for the Forbordfjellet railway tunnel. Engineering geological feasibility studies have been carried out for a single track railway tunnel. Two alternative routes with lengths of 4880 m and 6380 m have been investigated. The rocks are low metamorphic sedimentary and volcanic rocks (greenstones). Cost estimates indicate that a TBM-bored tunnel is slightly more expensive than a conventional drill and blast tunnel.

125 Institutt for geologi og bergteknikk Hovedoppgaver 1993

1993

Abrahamsen, A. and Husby, J.V. (B. Nilsen)

Hitra subsea road tunnel - evaluation of excavation results.

The Hitra tunnel is a 5.6 km / 75 m2 road tunnel going down to a maximum depth of 263 m below the sea level. Based on co-operation between the departments of Geology and Mineral Resources Engineering and Construction Engineering, the effects of use of 64 mm diameter instead of the conventional 45 mm for blastholes are evaluated. It is found that use of 64 mm holes can offer considerable time and cost reduction.

Arnesen, D.M. Schistad (S.O. Johnsen / Statoil)

A study of the effect some key parameters in stochastic modelling have on a two-phase displacement process. A sensitivity study of correlation lengths in a spherical variogram and p-values in the Box-Cox transform, and the effects these have on a two-phase displacement process. The basis is a stochastic generated facies model of a heterogeneous and layered reservoir deposited in a coastal environment. Stochastic petrophysical modelling on the faciesmodel, upscaling of the petrophysical models, flow simulations of gas injection and a summing up based on regressionanalysis is included. The results shows that correlation lengths and P-transforms have little effect on the recovery factor, but relatively large effect on the time to gas penetration.

Avseth, Per Åge (S.O. Johnsen / N. Hydro)

Structural setting and sedimentary signatures in a sequence stratigraphic framework, Early Cretaceous, Tampen Spur area.

Two models to explain the variation in clastic input and associated facies variations are presented. According to the first model the relatively high clastic input is due to a relative rise in sea level and therefore more open conditions. Hard- grounds are formed as a result of a eustatic sea level fall and a more isolated Tampen Spur area. The alternative model relates the relatively high clastic input to a regressive period due to a eustatic sea level fall. The hardgrounds are asso- ciated with transgressions, drowning of the hinterlands and reduced clastic input.

Brodahl, E. (S. Lippard / Statoil)

Fault patterns in north Somerset, England. This was a field-based study of mainly extensional normal faults along a 6 km long coastal section. Aerial photographs were used in conjunction with the mapping and a detailed cliff profile was constructed based on photos and measure- ments taken in the field. All faults, with displacements between 20 cm and 70 m, were mapped and measured. The size distribution of the faults shows fractal behaviour but only within a restricted range. Possible correlations between fault size and width of the fault zone and with the host lithology were investigated.

Buran, H. (E. Roaldset / Saga)

Simulation of faults in hydrocarbon reservoirs by the FASIMO programme.

The fault modelling programme FASIMO was tested on field observations from reservoir analogue formations, and on structural geological data from a comparable North Sea reservoir. The fault modelling by the FASIMO programme is based on a combination of a deterministic and a stochastic approach. By testing the programme on these two cases it became evident that many of the input parameters needed in the model had not been satisfactory described. This was in particular the case for the length and throw of faults, and the sealing properties of faults.

Fjeld, Anders (B. Nilsen)

TBM Muck for Construction Applications. The principal objective of the research was to determine the potential use and applicability of TBM muck for invert structures, especially as fill, at Yucca Mountain, Nevada. The site is being investigated as a potential future repository for high-level nuclear waste. A laboratory tunnel boring machine (TBM) was used to generate muck from the actual samples of welded tuff. Comprehensive literature studies and laboratory testing were carried out. According to relevant standards the TBM muck can be used for a variety of purposes like subgrade/fill and subbase in rigid roadway design without processing, and for additional purposes like subbase and base in flexible roadway design by simply screening off the +50 mm fraction.

126 Institutt for geologi og bergteknikk Hovedoppgaver 1993

Flornes, Svein (K.L. Sandvik)

Evaluation of Local Hazardous Waste Collection- and receiving systems.

Local collection- and receiving systems for hazardous waste from small amount sources (householdings etc) are evalu- ated concerning structure, accessibility, adaptability, safety, efficiency and information. Attempts to calculate the costs for investment, operation and destruction for such local receiving systems are also made. The evaluation shows that the already established systems have both strong and weak sides, but it do take care of the waste in a correct and proper way. This is why most of the districts seem satisfied with the existing systems, which again presents new tasks to be solved soon. As it is today, it is difficult to compare the different systems efficiency, because of the variations in calculating the mass of the collected waste and how to book the costs in the different districts. From the evaluation, it appears that most districts give the accessibility first priority, which have given today‟s collection- and receiving stations.

Gether, Harald (R. Sinding-Larsen)

Development of natural stone resources - A strategy approach. The purpose of this thesis has been to find ways and means to maximise “benefit to society” from natural stone resources, and to examine the contribution of modern strategic planning and management. Strategic theory and an extensive case study of a Norwegian natural stone company provides insight to this end. The Norwegian stone industry consists of small companies essentially producing raw materials (“blocks”) of which, in the case of Larvikite 97 percent is further processed abroad. Of a world production of 32 million tons of blocks in 1990, the Norwegian part was just over 0.6 percent. This, however, was about 2.3 percent of the world trade for blocks. The industry in 1990 exported natural stone for 558 million NOK: Approximately 70 percent of the exports was Larvikite. In all this provided jobs for 2000 persons. Existing processing equipment favours large blocks, and the requirements for homogeneity and freedom for cracks is one reason for high wastage. For Larvikite it may be in excess of 90 percent with respect to unmined rock, with 30 to 40 percent of the remainder being lost in further processing. More of the quarried stone might be utilized if processing occurred closer to the quarries. “Slabs” and “tiles” are the main products from processing. Slabs have a wide spectrum of uses, a major one being for exterior walls. Tiles are used mostly for floors. If more of the value generated from natural stone is to benefit Norway, then more of the processing must take place here. Several courses are possible towards “benefit to society”. This thesis concentrates on the existing Norwegian stone companies, and extension of their operations towards finished goods. Much of existing technical and market know-how reside in these companies. Also, competing companies form the basis for the theory of strategic planning and management. The main focus here is upon a strategy case study of one particular company: Johs. Grønseth & Co. A/S. The approach is twofold; firstly there is a fairly extensive description of theoretic concepts and tools, which are then applied in the case study for exports to the US West Coast area.

Hetle Mari Anne / Naustan, K. (K.L. Sandvik / Conoco)

Hazard and Risk Assessment in the Discharge of Production Chemicals Offshore. Norway and The Netherlands have taken the initiative to develop an environmental risk/hazard evaluation model for offshore exploration and production chemicals. TNO and Aquateam are commissioned to develop this model. The project, called Memorandum of Understanding (MoU), started in April 1993 and is not yet finished. The present version of the model calculates a Predicted Environmental Concentration, which is devided by a No-Effect Concentration. The resulting quotients indicate which chemicals are of high, medium and low hazard/risk. Here, the model are explained and hazard- and risk quotients for five production chemicals are calculated. The MoU model has already proved to be a good procedure for rapidly and routinely evaluating the ecological hazards/risks associated with the use of offshore chemicals. It is simple and logical. In the present phase it is best suited for ranking chemicals on the basis of total environmental risk.

Hille, Øyvind (K.L. Sandvik / Asplan Viak Stavanger Nor)

Disposal of abandoned Ekofisk installations. Today‟s Ekofisk installations are to be replaced in the next decades. This represents a challenge; to find the best environmental and economical solutions. Several alternative plans for disposal of the old installations are discussed in general terms, and parameters like safety, economics, (inter-) national law and environmental care are taken into con- sideration. The alternatives vary from (almost) total removal to “topping” (to cut off / dump the installations over the

127 Institutt for geologi og bergteknikk Hovedoppgaver 1993 sealine). As a general conclusion, installations of steel together with pipelines over the seabed should be removed, while installations of concrete should be individual by considered from case to case. Concerning the Ekofisk, a combination of total removal and “topping” is recommended, which means that the steel platforms are removed while the tank and wall (of concrete) are dumped. In addition to this, the pipelines over the seabed should be removed.

Holmøy, Kristin Hilde (K. Nielsen / Skifer & Naturstein Avd. Otta)

Pre-feasibility study of underground mining of schist from the Pillarguri orebody at Otta, Norway. The Pillarguri Schist quarry mines a bench dipping at about 30°. This means that the operation must remove an increasing amount of waste material as the excavation proceeds down-dip. The study was mainly done in order to evaluate how long it would be feasible to work a quarry before changing to an underground operation. The study looked into the design and production system of an underground schist mine based on extensive use of diamond wire cutting technology. Based on an economic comparison with the present quarry costs, it was conclude that the company should continue their quarry operation for at least 10 years.

Holt, Erling (B. Brattli / NGU)

Evaluation of the ball mill test, impact value, flakiness and abrasion value for hard rock aggregates crushed from production and in laboratory. In the first part of the investigation it is found that the impact value, flakiness and abrasion value are to a certain degree dependent on how the aggregates have been crushed. The values are usually better for laboratory crushed rocks compared to materials crushed from production. The “new” ball mill method, however, seems to give results which are independent of the crushing methods. The second part deals with the correlation between the results from the ball mill test and the other methods. It is found a good correlation between the ball mill values and the abrasion values, while there is no correlation (or very poor correlation) between the ball mill values and the impact values and flakiness.

Husby, Jan Vidar (B. Nilsen / A. Bruland, IBA)

Hitra subsea road tunnel - evaluation of excavation results.

The Hitra tunnel is a 5.6 km / 75 m2 road tunnel going down to a maximum depth of 263 m below the sea level. Based on co-operation between the departments of Geology and Mineral Resources Engineering and Construction Engineering, the effects of use of 64 mm diameter instead of the conventional 45 mm for blastholes are evaluated. It is found that use of 64 mm holes can offer considerable time and cost reduction.

Jøssund, Tor-Ole (F.M. Vokes / T. Grenne, NGU)

A geological investigation of the Skrattåsen Zn-Pb-Cu deposit and its surroundings, N.-Trøndelag. The lithology hosting the Skratåsen stratabound sulphide deposit in the Upper Allochthon of the Scandinavian Caledo- nides, 90 km NE of Trondheim, consists of alternating felsic, intermediate and mafic volcanic and volcaniclastic rocks deposited in submarine conditions, probably during the transition from an island-arc to a marginal basin-spreading environment. The thin layers of syngenetically deposited massive Zn, Pb, Cu and Fe sulphides were severely deformed and metamorphosed together with their host rocks during the Caledonian orogeny.

Krokeide, Cecilie (E. Roaldset / Saga)

The mechanical properties of shale in relation to content of organic material and mineralogical composition. Borehole problems during drilling and completion of offshore wells often occur as a consequence of mechanical instability in the borehole when penetrating unconsolidated and weakly consolidated claystones and shales. This thesis is particularly directed towards the properties of organic rich shales in some Northern North Sea wells. Mechanical properties are considered in relation to mineralogical composition and organic matter characteristics.

Larsen, K. (A. Myrvang)

Evaluation of rock support in the No. 7 coal mine, Svalbard. Convergence measurements were carried out to evaluate the existing rock bolt system. As a result, shorter bolts were recommended, giving a substantial cost reduction potential.

128 Institutt for geologi og bergteknikk Hovedoppgaver 1993

Molund, Sissel (F.M. Vokes / NGU)

An ore geological investigation of the Sinklien and related Zn deposits, Ballangen, Nordland

Sinklien is the most prominent of a series of small stratabound Zn-rich sulphide deposits along the eastern flank of the Ofoten syndrome, near Nark. Sulphide mineralization, - a massive pyrite layer and a breccia vein type carrying mainly sphalerite, occur towards the structural top of a massive dolomite lens in a thick carbonate sequence. Both types show clear effects of a metamorphic/deformational phase of the Caledonian orogeny, but it is concluded that they were originally deposited by syngenetic exhalative processes in a shallow marine environment.

Naustan, Kåre / M. A. Hetle (K.L. Sandvik / Conoco)

Hazard and Risk Assessment in the Discharge of Production Chemicals Offshore. Norway and The Netherlands have taken the initiative to develop an environmental risk/hazard evaluation model for offshore exploration and production chemicals. TNO and Aquateam are commissioned to develop this model. The project, called Memorandum of Understanding (MoU), started in April 1993 and is not yet finished. The present version of the model calculates a Predicted Environmental Concentration, which is devided by a No-Effect Concentration. The resulting quotients indicate which chemicals are of high, medium and low hazard/risk. Here, the model are explained and hazard- and risk quotients for five production chemicals are calculated. The MoU model has already proved to be a good procedure for rapidly and routinely evaluating the ecological hazards/risks associated with the use of offshore chemicals. It is simple and logical. In the present phase it is best suited for ranking chemicals on the basis of total environmental risk.

Nilsen, Frank (B. Nilsen)

Testing of a new polyester rock anchoring concept. A common source of malfunctioning of polyester anchored rock bolts is that the drillhole is too long. As an attempt so solve this problem, new concepts for polyester anchoring are tested. The main idea is to place a buffer of soft or weak material in the bottom of the potentially too long hole. Several different materials (mainly plastic and polystyrene products) have been tested in laboratory and in an underground mine. The best anchoring effect in too long drillholes has been obtained with a brittle plastic material as buffer.

Nåvik, Kristin Sølvi (K.L. Sandvik / Sintef / NHL)

Flow towards a sink. Research is made on the connection between a sinks capacity and different rheologies in the oil phase, in a stratificated two-phase model. Experiments with both newtonian and non-newtonian fluids are made. Important parameters in these experiments are initial height between water/oil and sink, viscosity, density, speed of the pump, time for incoming water and cone heights at different pump speeds. Experiments with newtonian fluids (with low viscosity) gave only small cones even at a short distance to the sink. Oil/Water emulsions (with a high viscosity) gave steep cone profiles towards the water and even at very low pump rates it came water into the sink. Further experiments show that by increasing the speed of the pump in small steps, it is possible to reduce the height of the cone and in this way delay, or even stop, water to flow into the sink.

Omdahl, S. (S.O. Johnsen / Statoil)

Geometrical characterisation of small tributaries on the Niger Delta for use in stochastic modelling. LANDSAT images have been used to characterize the geometry of fluvial channels and meander belts in the upper parts of the Niger Delta. The results will be used to test stochastic reservoir modelling techniques.

Sandvik, Aina M. Husby (K.L. Sandvik / Aquateam A/S)

Sampling and characterising of tarsoil - development of procedures to minimize sources of error in characterising and washing of tarcontaminated soil. It is of great importance to develop procedures to minimise the sources of error in characterising and washing of tarcontaminated soil. The tar contents polyaromatic hydrocarbones (PAH), which are environmental damaging and may cause cancer. The purpose of the characterisation is to find the level of contamination, grain size distribution and the PAH distribution in the grain fractions. PAH were extracted from the samples using cyclohexan and water bath, whereas the extract was analysed by using gaschromatography. This showed that the extraction is a critical part of the sample

129 Institutt for geologi og bergteknikk Hovedoppgaver 1993 treatment, and it is therefore necessary to consider possible problems caused by the sampling to minimise the sources of error. Sampling is also considered concerning flotation (soil renediation) of contaminated soil. Here, filtration became the best sampling method in the water and the foam, while pipette or spoon with lid may be used for sampling in the clean soil.

Svela, P.E. (E. Roaldset / N. Hydro)

Petrophysical measurements calibrated against petrographical analyses, Ness formation, Oseberg Field. Log data are calibrated against petrological data by means of multivariate regression analysis and the correlation obtained is applied in interpreting the lithology of the non cored intervals. The main log parameters selected are density and sonic velocity as these parameters most easily are tied to the seismic. Calibration of log data against core samples described in detail is a necessary step in the effort improve the interpretation of sediment facies, composition and properties from well logs. To obtain correlation of acceptable quality the lithology had to be simplified to weather it was a sandstone or not, and outliers had to be omitted. It was then possible by means of density and sonic velocity to predict sandstone intervals in non-cored intervals of the wells studied.

Sylliaas, Ingrid (E. Roaldset / T. Malvik / Norsk Hydro)

Permeability related to porosity, petrography and depositional facies, Brent group, Oseberg South - a quantitative study with image anlysis. Different methods of image analysis are used to characterise crucial factors influensing the permeability of reservoir rocks. The results are correlated with other techniques used to determine the permeability and porosity of the rocks.

Tørudbakken, M. (S.O. Johnsen / Saga)

A sequence stratigraphic study of tertiary deposits over the NE parts of the Nordland Ridge and adjacent basins. Based on seismic and well data 6 sequences of palaeocene age have been mapped. Palaeocene sandstones (Tang Formation) are deposited in the eastern part of the area, landward of and on the flanks of the Helgeland Basin. An E-W oriented fan-system is deposited along the paleoaxis of the Vestfjord Basin. All the sequences are dominated by channel-facies. The source area for the sediments is probably to the east and south-east. The structural elements developed through Jura - Early Cretaceous. The main fault trend is E-W. The Lofoten Lineament, a NW-SE transform, has influenced the Early Tertiary deposits.

Veie, Anita (K.L. Sandvik / Veritas Industri Norge)

Environmental Impact - Sensivity Index. Theoretical methods are needed to foresee the environmental impact of coming oil spills. Several index models, including a new one, are here presented. These models calculate an index for the areas/environments sensitivity for oil concentrations. This is done by making a quantification, which is combined with accept criterias. The quantification results in an index which increases with the sensitivity of the environment. Reference indexes should be set before an area is polluted, but can also be set after a spill, if the biology of the area is well known. It is important that the calculation of indexes can be measured and recalculated without any change in result. After this calculation, the quantification indexes are set up against the accept criterias. Models for calculation of sensitivity have to be adjusted to the contaminated area. It is therefore important that the model is dynamic, so it includes the natural processes that influence the oil.

Aamodt, A.-H. (S. Lippard / N. Hydro)

Late Cretaceous and Tertiary geology of the Southern Offshore Malta Area. The structure and stratigraphy of an offshore part of the Malta Graben system was studied using seismic data tied to wells. The rifting phase, which occurred in post-Miocene times, affects the Pelagian Mesozoic carbonate platform. The extension phases resulted in complex fault patterns with trends ranging from WNW-ESE to ENE-WSW and several grabens can be recognised. Footwall uplift occurred on the graben flanks and syn-rift sediments formed, but the tectonic relief was maintained and the grabens are not completely filled. The present bathymetry is thus strongly influenced by the rifting events.

130 Institutt for geologi og bergteknikk Hovedoppgaver 1993

Aastorp, Grete L. (T. Prestvik)

Tolerance limits of surface waters in mountain areas of Opland, Norway.

The Acid Neutralizing Capacity (ANC), the tolerance limit and sum of nitrates and sulphates have been calculated from 166 lake localities. The sulphate values are generally above the limit for what could be expected to come from natural sources. The results also shows good comparison of fish-status and ANC. Rock- and soilsamples have been analysed to find the sensitivity to acid rain. A relatively high content of mica in the bedrock, mixed layer minerals, mica and chlorite in the soil protects the area against acidification.

131 Institutt for geologi og bergteknikk Hovedoppgaver 1992

1992

Andersen, R.E. (E. Roaldset / N. Hydro)

Reservoir quality in the upper parts of the Amundsen Formation in the block 30/6 area, Horda Platform, Northern North Sea. The reservoir quality of the upper parts of the Amundsen Formation was studied in selected 30/6- wells. On the basis of logs, cores and thin section descriptions the reservoir units were divided into four facies types. Models for prediction of porosity and permeability were tested in relation to burial depth, facies and clay mineral content. For the pure sandstones the porosity could be expressed as an exponential function of facies and burial depth, and also of clay content and burial depth. At depths below 2.5 km quarts cementation becomes prominent. For more immature sandstones the porosity with depth could be expressed as a smooth exponential curve, and the permeability as a function of reservoir facies and burial depth, and also of clay content and burial depth.

Aursand, Asle (B. Nilsen)

Nuclear waste disposal in rock caverns - a discussion with main emphasis on engineering geological criteria. Safe disposal of low- and intermediate-level nuclear waste is an urgent issue in many countries today. Based on review of experience from other countries and evaluation of Norwegian engineering geological conditions, the potential of the South-Norwegian bedrock for safe waste disposal is discussed. Certain parts of the Precambrian regions and the central parts of the Caledonian mountain range are found to be the best alternatives.

Bergan, Mette Ch. (B. Brattli)

Investigation of how the fine fraction (clay fraction) influence upon the binding adhesion forces between crushed rocks (aggregates) and bitumen. Mafic rocks like gabbro etc. produce more fine grained particles (dust) when crushed than felsic rocks. The fine fraction more or less adhere to the larger rock fractions influencing the finding forces between the aggregates and the binders (bitumen). Several adhesion tests have been carried out to investigate how the composition of the fine fraction affect the binding force. Especially smectite and clinozoisite in the fine fraction seems to lower the binding forces between aggregates and bitumen. To increase the adhesion in such cases the aggregates should be washed before use.

Berger, Jonny (A. Myrvang)

Quality assurance of rock support. Different aspects of ground reinforcement have been evaluated and discussed during this thesis. Fully grouted rock-bolts are evaluated in two steps by first visual inspection of the installation procedure and later by Boltometer measurements on the bolts. Visual inspection have been done during the shotcreting and rebound have been estimated. Water/cement-ratio measurements have been done, and found inside requirements. The quality plans have been evaluated against actually works carried out in the tunnel.

Bjørdal, Merete Elin (E. Broch)

An evaluation of the engineering geological preinvestigation for Gjøvik Olympic Mountain Hall. This cavern has by far the world‟s largest span: 61 m. A comprehensive preinvestigation program was carried out. During construction careful registration and mapping of all geological and rock mechanical factors were done. The investigations also included stress measurements and numerical modelling using different codes. The author gives a critical review of all methods and compare predicted and observed values. Correlation between predicted and measured deformation is very good for all numerical models.

Blekastad, T.T. (E. Roaldset / N. Hydro)

Permeability of reservoir sandstones, Troll field, Northern North Sea. Estimation of horizontal permeability from cores and well logs. Based on eletrical logs, core and facies descriptions of the Lower Jurassic Sognefjord Formation from four wells, the Troll Field, multivariate statistical analysis attemting to correlate the data obtained from well logs to the reservoir permeability were undertaken. The well data were mainly analysed by principal component analysis (PCA) and least squares regression (PLS). The logs needed for obtaining a reliable regression model are gamma ray, spectral gamma

132 Institutt for geologi og bergteknikk Hovedoppgaver 1992 ray, neutron, density, microspheric focussed and acoustic logs. A model for estimating the permeability from regression equation by PLS-regression, where well logs are the independent and the horizontal plug permeability the dependent variables, was developed.

Busklein, Mari M. (K.L.Sandvik / Elkem Nefelin)

Quality Assurance in the Concentration Plant of Elkem Nefelin. In this work the candidate examines and describes the routines for quality assurance in selected and parts of the concentration plant of North Cape Minerals (former Elkem Nepheline). Suggestions how to improve the routines are given as well as the inplementation and testing of new routines. Charts to carry out statistic quality control and statistic process control are worked out. A course for training the operators in quality assurance have been made and given to the staff.

Ersdal, G. (P. Aagaard, UiO / E. Roaldset, Cand.scient)

Swelling pressures in clays and claystones. By investigating of problematic clays from on- and offshore Scandinavia representing different geological settings (glaciomarine and young marine clays, clays from remnants of preglacial weathering, problematic rock fractures penetrated in tunnelling work, the Norwegian shelf, and pure reference clays smectite and kaolinite) the influence of mineralogical and geochemical composition on the swelling behaviour are outlined. The main swelling minerals are smectite and smectite/illite. The smectite content is positively correlated with the cation exchange capacity, while no absolute correlation was found between the smectite content and the swelling pressure. This is partly explained by different kind of exchangeable cations. Na+ and Ca2+ are the main interlayer cations. While Na+ is positively correlated Ca2+ is negatively correlated to the swelling ability. The smectites with the lowest charge cause the largest swelling pressures. Swelling pressures up to 2 MPa was measured for the most active offshore clays of Tertiary age.

Faaberg, M.M. (S.O. Johnsen)

Dipmeter analysis and structural evaluation of parts of the Gullfaks field. Dipmeter data from 4 wells in the Gullfaks Field have been interpreted by the use of Statistical Curvature Analysis Techniques (SCAT-analysis). Structural profiles based on the interpreted dipmeter data have been compared with seismic sections. The results show good correspondence. By applying SCAT-analysis a more detailed and accurate structural interpretation of the area around the wells was obtained.

Granberg, E. (S. Lippard / Philips)

A basin modelling study of the Vøring basin. 1D basin modelling was carried out on 6 pseudowells in the Vøring Basin located on depth-converted seismic lines. A model for the, temperature history of the basin was established from maturity modelling of commercial wells in the Haltenbanken/Nordland Ridge, area and published heat flow data. The results of the modelling suggest that the Vøring Basin is a high risk area for petroleum exploration.

Hedalen, Tom (T. Myran)

Visual range and air pollution distribution in longitudinal ventilated road tunnels. The influence of air pollution on the visual range and measurements of tunnel pollution distribution related to climate, traffic and ventilation.

Husby, Kjetil (K.L. Sandvik / Grong Gruber)

A survey of water solvable sulphur componds in the process water of the Grong Gruber concentrator Flotation results may be affected by the formation of thiosulphates and similar compounds resulting from oxidation of pyrite ores during grinding and flotation. Grong Gruber experienced poorer flotation performance after their process water system was closed via recirculation of water from the tailing pond. The flotation circuit was therefore surveyed with respect to thiosulphates a number of times during fall and winter to investigate the effects of recirculation upon thiosulphate levels in the water when ice prevented thiosulphate oxidation. Little effect could be found. The mode and points of lime addition proved to be more important.

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Håkonsen, Jo Grunnar Eggen (A. Myrvang)

In-situ of the adhesivity of shotcrete.

A field device using a hydraulic fracturing principle for determination of adhesivity to the rock was tested, and compared with conventional pulling tests. The results were promising.

Ingebrigtsen,M. (E. Roaldset /Amerada Hess)

Regional mapping of potential reservoir rocks along the margins of the Loppa High, Western Barents Sea. The study is directed towards a better understanding of the reservoir potential along the Loppa High, extension and reservoir quality of potential reservoir units. The Permo-Carboniferous carbonate deposits are widely distributed on the Barents Sea Shelf, but are buried to depths were the primary porosity is completely destroyed and secondary porosity hardly developed. An unit with possible reservoir quality is of Upper Carboniferous age. Triassic fluvial sands may have reservoir quality, but are of low continuity. The best reservoir sands are the Jurassic Stø and Tubåen formations, but for these problems related to the geological setting of the source rocks in relation to the potential reservoir units may exist. The Upper Jurassic/Lower Cretaceous sandstones along the Loppa High, may have reservoir quality with respect to porosity and permeability. Although possible reservoir rocks exist, hydrocarbon filled reservoirs have so far not been found.

Julseth, I. (S. Lippard / N. Hydro)

Late Jurassic and early Cretaceous on the southern part of the Trøndelag. Platform and Halten Terrace - stratigraphic, structural and paleo-,topographic relations. The relief and erosion/sedimentation patterns in the area are largely controlled by a rifting phase which started in the late Oxfordian and continued into the Kimmeridgian and early Volgian when the Spekk and Rogn formations were deposited. From mid Volgian to Ryazanian the tectonic activity decreased and the Frøya High, which had been uplifted and eroded during the rift phase, was transgressed. Cretaceous sediments drape and infill the paleotopography formed by the rifting.

Larsen, Freddy Roar Garnes (A. Myrvang)

Optimisation of roof bolt costs in mine No. 7, Longyearbyen. The thesis comprises theoretical and practical trials carried out in the no. 7 coal-mine in Longyearbyen, Spitzbergen. Reduction of rock-bolt lengths from 1 200 mm to 900 mm were done without any measurable difference in roof sag. The support pattern with originally 6 bolts per row to 4 bolts were tried, with the same result. The mining method in the mine is room & pillar. The development pattern were modified and analysed to evaluate the costs.

Laugtug, B. (S.O. Johnsen / Esso)

Seismic and sequence stratigraphic analysis of the Lower Tertiary - Paleocene-Eocene in the South Viking Graben area. A regional sequence stratigraphic framework of the Palaeocene - Eocene interval in the Sleipner area has been established through the interpretation of regional seismic lines. Different depositional units have been traced over the whole study area, from shallow shelf margin units to deeper submarine fan units. The submarine fan sandstones pinch- out on structural highs to the east. Four shaly sequences seem to be the distal equivalents. The main direction of sediment transport is from the west, but locally also from the east.

Lindgaard, Ingunn (T. Myran)

Visibility studies for vehicular tunnels. Use of visibility meters for tunnel ventilation control.

Løkse, Audun (E. Broch)

Durability and long-term performance of rockbolts. A survey of previous and current research on the subject of the long-term performance of rock bolts was conducted by 1. writing to the national representatives of the International Association and 2. conducting a literature search using the library at the University of Minnesota. Included is a summary of the use of rock bolts today, the type of deterioration to which they may be exposed, as well as what precautions may be taken to avoid the most common long-term damage to rock bolts, namely corrosion. The roof of a special underground test room on the campus of the University of Minnesota is supported by 15 year old full column resin grouted rock bolts. The design and function of this room is discussed. Two

134 Institutt for geologi og bergteknikk Hovedoppgaver 1992 of the rock bolts in the test room roof were selected and overcored to examine actual effects of prolonged exposure to the environment. From these investigations it was concluded that the passing of time had not had any profound effects on the quality of the rock bolt installation. The quality of work done during installation appeared to be satisfactorily high, and the resin had protected the bolts from corrosion and had not itself started to deteriorate.

Mikkelsen, Oddbjørg (T. Moseid)

The Gardermoen glaciofluvial deposits - Application of in situ methods for the treatment of polluted soil with emphasis on the unsaturated zone. The soils of the Gardermoen area are considered with respect to their suitability for in situ remediation techniques. The sedimentological and hydrological characteristics were studied in the field, 80 soil samples were taken to the laboratory for grain size and mineralogical analysis, and water from 5 test wells were analysed for chemical species. Two techniques for remediation of polluted soil were considered, namely soil washing and in situ bio-restoration. It was concluded that both gave satisfactory results under most, but not all, conditions.

Moa, Guri (T. Moseid)

The Gardermoen glaciofluvial deposits - Application of in situ methods for the treatment of polluted soil with emphasis on the saturated zone. The thesis consists of field and laboratory studies. The field work included Quaternary geological mapping, probe borings, pumping tests and sampling. The sand samples were investigated with respect to grain size distribution and mineralogical composition. The pH, temperature and conductivity of the ground water were measured in the field, and later in the laboratory analysed for dissolved ions. As the dominant pollutants at Gardermoen will be aeroplane fuel and deiceing fluids, which are easily degradable, it is assumed that most of the pollution can be destructed by micro- organisms, i. e. by the in situ bio-restoration technique.

Netland, Knut (A. Myrvang)

Evaluation of rock support in the Svea coal mine, Svalbard. A number of rock support systems possible for the access to the so-called Central field are evaluated, ending up in a recommendation for support for different sections of the mine. Fully cemented resin rebars is the main system.

Pedersen, J. (S. Lippard / Philips)

Late Tertiary uplift and erosion in the Skagerrak area; magnitude and consequences for hydrocarbon exploration in the Farsund basin. The amount of late Tertiary uplift and erosion was calculated by paleogeographic reconstruction of depth-converted cross sections. Modelling of pseudowells in the Farsund Basin shows the depths at which the late Jurassic source rock reaches the mid-mature window for main oil generation for the minimum, expected and maximum cases of late Tertiary uplift and erosion. Sensitivity, analyses of the results with respect to depth conversion, changes in the timing of the uplift and erosion and kerogene composition‟ of the source rock were carried out.

Skardal, Ole Ingvald (K. Nielsen)

Design of two limestone quarries in Velfjord, North Norway. The thesis presents a pre-feasibility design of two separate quarries on a large limestone formation. The limestone is suited for filler production. The study encompassed basic quarry designs, tonnage estimates, primary crushing and materials handling facilities, and environmental aspects with regard to noise pollution and mine water run-off into the adjacent fjord.

Skjerdingstad, Steinar (E. Broch)

The Avise Tunnel in the Aosta Valley, Italy. Italian tunneling technology is reviewed through the example of the Avise tunnel in Aosta Valley, a 3000 m twin bore motorway tunnel. Along the tunnel axis three different geological sections can be found. During the time the study was carried out, the hard rock part was under construction. Previously, a 4.5 m diameter pilot tunnel was bored. The enlargement is fulfilled by a 11.4 m diameter reaming machine in the right tube and by drill and blast in the left. The

135 Institutt for geologi og bergteknikk Hovedoppgaver 1992 report describes the geological investigations, excavation methods and occurring problems connected to this part of the tunnel. The advance data are studied and compared with the geological factors.

Skotte, G. (E. Roaldset / N. Hydro)

Quantitative 3D reservoir modelling of the flank areas of the Ekofisk field. The intention by the thesis work was to establish a revised geological model for the Ekofisk field with special emphasis on the flank areas and their possible additional reserves. In the Ekofisk field the hydrocarbon reserves are unevenly distributed between the Tor (17 %) and Ekofisk formation (83 %), and the type of lithofacies (8 types classified) are strongly influencing the amount of reserves that can be produced from the different units. The estimated quantities may vary depending on the cut off values used in the sensitivity tests. In conclusion, the flank areas may contain considerable reserves that can be produced by deviated and horizontal wells.

Storhaug, Lisbeth (F.M. Vokes / Nikkel og Olivin)

An investigation of the influence of structural geological elements on the Fe-Ni-S mineralization in the eastern part of the Bruvann deposit, Ballangen, Nordland. The eastern part of the ultramafite-hosted Bruvann pyrrhotite-pentlandite-chalcopyrite-deposit in the Caledonian (435 Ma) RDna layered igneous complex was deformed, metamorphosed and intruded by pegmatites and basic dykes; sheet- like xenoliths of gneissose country rocks added further structural complexities. The influence of these elements on the nickel distribution in the ore was investigated by underground mapping and computer-assisted plotting of ore grades. The influence of the gneiss xenoliths in localising restricted but rich bodies of massive, probably mobilized, sulphides was established. The influence of the other structural elements was less obvious.

Thoresen, Stig Kjetil (E. Broch)

Rock stresses in the outer part of fjord- and valley sides.

Field investigations in road tunnels show that variations in stress fields from tunnel to tunnel not only depends on the topographical conditions. Thus the mathematical models give a too simple picture of the real situation. The observations show that tunnels in the outer parts of valley- and fjord sides have less stress induced stability problems than the theoretical models indicate. Suggestions for adjustments of models are presented.

Tørum, G. (S.O. Johnsen / Elf)

Carbonate cementation; origin, extension and influence on production, quadrangle 25. The sandstones in quadrangle 25 contain numerous carbonate-cemented horizons with thickness up to 2,6 m. Most of the carbonate are deposited in the top of the Brent Group (Tarbert Fm.)

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