DOCSLIB.ORG

Lithofacies and Associated Petrophysical Properties

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lithofacies and Associated Petrophysical Properties Lithofacies Lithofacies and Associated Petrophysical Properties Classification Lithofacies Prediction: Tools, Methods, Results Rock properties data represent analyses from 33 wells (below) that have attempted to sample the complete range in porosity, permeability, geographic Lithofacies, Porosity, Permeability BA L- 8 Phyloid Algal Bafflestone Gamma Ray PE Effect distribution, and formational unit for each of the logk=Alogfi+B or k=10 fi: Keystone Wells PE vs. Delta Phi (N-D) by Lithofacies Fundamental to construction of the reservoir geomodel is the population Log Response and major lithofacies. Lithofacies were described for Steps to Predict 20 Permeability Permeability Permeability Standard Standard Lithofacies Digital Description: 3-8 / 7 L1 NM Silt&Sd L2 NM ShySilt core using a digital classification system to facilitate of cells with the basic lithofacies and their associated petrophysical 8 8 data management and because it offered the ability properties- porosity, permeability, and fluid saturation. Petrophysical Lithology Lithology Equation Equation Adjusted Error Error * Primary Depositional Environments: L- 8 Grainstones L3 Mar Sh&Silt L4 Mar Mdst Lithofacies Code A B R^2 (log units) (factor) L5 Mar Wkst L6 Mar Dol 7 7 L-7 Packstone and Packstone-Grainstone Lithofacies Shankle to use non-parametric categorical analysis. Digits L7 Mar Pkst L8 Mar Grnst&PA 1 NM Silt & Sand 7.861 -9.430 0.780 0.769 5.9 ) properties vary between the eight major lithofacies classified (see lower Lithofacies Digital Description: 3-8 / 6 n Thin Section Photomicrograph o 6 6 i Newby 2-28R t generally represent continuous variation of a s s 2 NM ShlySilt 5.963 -7.895 0.702 0.787 6.1 c 10 e Lithofacies Digital Description: 3-8 / 4-5 Primary Depositional Environments: e e r left). Mean and maximum porosities increase with increasing lithofacies Shrimplin i i Core Slab, 2992' Beaty r The eight lithofacies can be discriminated c c lithologic property that may be correlated with o 5 5 3 Mar Shale & Silt 8.718 -10.961 0.719 0.847 7.0 c Primary Depositional Environments: Shoals on mid to upper shelf in either regressive or transgressive phase. In Non-cored Wells a a f f e Cottonwood Limestone (B5) l a number for the limestones (mud- to grainstone; histograms below). In situ o o petrophysical properties. Final petrophysical trends 4 Mdst/Mdst-Wkst 7.977 -9.680 0.588 0.958 9.1 h effectively by four wireline log properties. Although 4 4 h h Shoals on mid to upper shelf in either regressive or transgressive s t t i i o n L L used the eight major lithofacies shown below 5 Wkst/Wkst-Pkst 6.260 -7.528 0.774 0.611 4.1 ( (stressed) porosities ( fi) were either measured or were calculated from phase, lagoons and tidal flats. Alexander D-2 M-CG Oncoid-Pellet Alexander the log distributions of the separate lithofacies 3 3 (selection process is discussed further on). 6 Sucrosic (Dol) 7.098 -8.706 0.643 0.673 4.7 Core Slab, 3024 Grainstone ) 0 routine helium porosity (f ) values using the developed correlation: f = Determine predictor variables, lithofacies % 2 2 routine i Beaty E-2 ( show overlaps in their ranges, their collective use 7 Pkst/Pkst-Grnst 6.172 -6.816 0.840 0.521 3.3 FG Pellet Cottonwood Limestone (B5) 8 Grnst/PA Baff 8.240 -8.440 0.684 0.600 4.0 Core Slab, 2782' categories, and optimal predictor tool in an Luke i within multivariate statistical analysis results in 1 1 Core Analysis Data 1.00froutine-0.68. Packstone-Grnst Stuart h Morrill Limestone (B4) P iterative, logic-based, trial and error process. good predictions of lithofacies identity as decisions All All Digital Description: 56-505-505-414-9434 a t At porosities below approximately 6% some facies exhibited higher Digital Description: 55-503-314-9424 Newby l -10 0.5 mm e Permeability is a function of several variables including primarily pore Routine Core Analysis: rooted in probability. 0 50 100 150 1 2 3 4 5 6 7 Routine Core Analysis: D permeabilities than predicted by the power-law function. For these Whole Core Porosity (%) 18.8 GR (API units) PE (barns) throat size, porosity, grain size and packing (which controls pore body size Whole CorePorosity (%) 11.8 Digital Description: 57-607-744-1534 Perm Max (md) 39.0 Optimize neural network parameters through facies the relationship between permeability and porosity was best Perm Max (md) 1.8 Routine Core Analysis: Plug Porosity (%) 21.8 Kimzey Shankle and distribution), and bedding architecture. Equations were developed to Gamma-ray log contrasts the generally low radioactivity within i3 Plug 1 Porosity (%) 20.6 Perm (md) 30.3 cross-validation and logic-based trial and error. predict permeability and water saturation using porosity as the represented by an equation of the form: logki = A logf + B. Plug Porosity (%) 13.7 -20 the carbonates to higher levels emitted from clay minerals and silt RT (apparent) Delta Phi (N-D) Perm(md) 3.3 Perm (md) 1141 (Keystone wells) fractions. Plug 2 Porosity (%) 15.4 2 3 4 5 6 7 Shrimplin independent variable because porosity data are the most economic and Beaty Perm (md) 73.1 one for Photo Electric Effect (barns) 8 abundant, and because porosity is well correlated with the other variables Standard error of prediction ranges from a factor of 3.3 to 9.1. At fi Select two neural network models, 8 Photoelectric effect is a direct function of the lithofacies for a given lithofacies. > 6% permeability in grainstone/ bafflestones can be 30X greater wells with PE curve and one for wells without PE curve. 7 7 aggregate atomic number and can be related to mineral content. 6 6 Alexander than mudstones and >100X greater than marine siltstones of similar s PE vs. Core Grain Density by Lithofacies s e i e i Kipling c 5 porosity. Differences in permeabilities between nonmarine silt/ c 5 In situ Klinkenberg (high-pressure gas or liquid-equivalent) gas a f Develop code to automate process of 2.9 a is sensitive to both pore volume and pore fluid f L1 NM Silt&Sd L2 NM ShySilt Resistivity log o CMAC o 4 sandstones and shaly siltstones range from 3.3X at 12% porosity to 4 h t permeability (k) exhibits a log-log correlation, or power-law, relationship h i generating the Marine-Non Marine curves and neural L3 Mar Sh&Silt L4 Mar Mdst t content in the carbonates as well as conductivity caused by clay i Luke L L5 Mar Wkst L6 Mar Dol L 3 3 Stuart with porosity though the relationship changes in some facies at porosities 7X at 18%. Regression analysis required careful data filtering such mineral cation-exchange properties in the shaly lithofacies. network predictions. L7 Mar Pkst L8 Mar Grnst&PA 2 2 below ~6%. Each lithofacies exhibits a relatively unique k-f correlation as to removed data from fractured samples. Full-diameter cores 0.5 mm 0.5 mm ) c 2.8 c 1 1 frequently exhibit permeabilities as great as 50X plug permeabilities / Newby that can be represented using equations of the form: Delta Phi transform (neutron minus density porosity) is Thin Section Photomicrograph Close-up Core Slab Close-up Core Slab Thin Section Photomicrograph Close-up Core Slab due to stress relief fracturing. Generate predicted lithofacies and probability m highly correlated with the grain density of the lithofacies and is All All g curves and output LAS format files through batch ( y 0.1 1 10 100 -20 -10 0 10 20 30 t Kimzey i 2.7 Rta (ohms) Phi Units (%) processing of input LAS files. s n PE Rock L-5 Wackestones and Wkst-Packstones e Mudstones-Bafflestones 5.1 Limestone Porosity Histogram Porosity Histogram D 5.1 Anhydrite L1 NM Silt & Sd L5 Mar Wkst (Key wells are named) n 100 Lithofacies Digital Description: 3-8 / 2-3 i NM Clastics Limestones 1.8-6.3 Shale (~3.4 is common) 30% a 25% r 2.6 ) Primary Depositional Environments: Mdst/Mdst-Wkst L4 3.1 Dolomite NM Silt & Sand L1 G d Automation Mostly in carbonate dominated mid shelf, some lagoon and tidal flat 1.8 - 2.7 Sandstone (Qtz = 1.81) L2 NM Shaly Silt L6 Mar Dol s Wkst/Wkst-Pkst L5 NM Shaly Silt L2 s L-4 Mudstones and Mdst- Wackestones Kipling/CMAC tesselation of n 25% m n 10 Significant custom programming by Bohling has made Density Rock ( o 20% Pkst/Pkst-Grnst L7 o i by: Alan Byrnes, Martin Dubois i Newby 2-28R predictor variable (well log) space Digital Rock Classification System t 2.88 Dolomite (2.83 on logs) t Lithofacies Digital Description: 3-8 / 0-1 y Algal-Mixed Skeletal possible the generation of the Marine-Nonmarine predictor a Grst/Grst-Baff L8 a l t l 20% Core Slab, 2986' in two and three dimensions. This 2.5 2.71 Limestone L3 Mar Silt & Sh L7 Mar Pkst Primary Depositional Environments: i DIGIT # 1 2 3 4 5 6 u u l Wackestone variable LAS curve through a Visual Basic routine in MS p 15% i Cottonwood Limestone (B5) 2.65 Sandstone Rock Dunham/Folk Consolidation/Fracturing Argillaceous Grain Principal p CODE Siliciclastic or carbonate dominated mid shelf. non-parametric classification 2 3 4 5 6 7 o Type Classification Content Size Pore Type o 1 b Access that allowed the mining of the KGS Oracle data 2.98 Anhydrtite P 9 Evaporite cobble conglomerate unconsolidated Frac-fill 10-50% vcrs rudite/cobble congl (>64mm) cavern vmf (>64mm) P 15% technique was considered but not a Photo Electric Effect (barns) L4 Mar Mdst L8 Mar Grnst & PA f 8 Dolomite sucrosic/pebble conglomerate poorly cemented, high porosity Frac-fill 5-10% med-crs rudite/pebble congl (4-64mm) med-lrg vmf (4-64mm) f Digital Description: 52-081-014-1413 Variable Shale e base, automated cross-validation exercises via R-language o o Thin Section Photomicrograph 7 Dolomite-Limestone baffle-boundstone/vcrs sandstone cemented, >10% porosity, highly fractured Shale >90% fn rudite/vcrs sand (1-4mm) sm vmf (1-4mm) 10% Silty Wackestone used in favor of the neural net.
Load more

Recommended publications
  • A Brief History of Till Research and Developing Nomenclature
    k 7 2 A Brief History of Till Research and Developing Nomenclature With relief one remembers that, after all, the facts gathered with such infinite care, over so many years, are in no ways affected: their permanency is untouched, their value as high as ever. It is the interpretation which has gone astray. Carruthers (1953, p. 36) A benchmark publication in the development of till nomenclature was contained in the final report by the INQUA Commission on Genesis and Lithology of Glacial Quaternary Deposits, entitled ‘Genetic Classification of Glacigenic Deposits’ (Goldthwait and Matsch, 1989; Figure 2.1). Most significant in this report was the paper by Aleksis Dreimanis (Figure 2.2), entitled ‘Tills: Their Genetic Terminology k k and Classification’, a summary of the findings of the Till Work Group, which operated over the period 1974–1986. It was a synthesis of knowledge and a rationale for a unified process-based nomenclature but at the same time afforded the presentation of alternative standpoints on till classification, and hence delivered a selection of frameworks containing complex and overlapping genetic terms. More broadly, ‘till’ at this juncture was defined as: a sediment that has been transported and is subsequently deposited by or from glacier ice, with little or no sorting by water. (Dreimanis and Lundqvist, 1984, p. 9) As a way forward, the Till Work Group, through Dreimanis (1989), arrived at a series of nomencla- ture diagrams (Figure 2.3), which aimed at an inclusive but at the same time simplified and unambigu- ous, process-based till classification scheme. More specifically, Dreimanis (1989), within the same volume, compiled a table of diagnostic characteristics for differentiating what he termed ‘lodgement till’, ‘melt-out till’ and ‘gravity flowtill’.
    [Show full text]
  • Style, Scale and Significance of Sand Bodies in the Northern and Central Belts, Southwest Southern Uplands
    Journal ofthe Geological Society, London, Vol. 144, 1987, pp. 787-805, 13 figs, 3 tables, Printed in Northern Ireland Style, scale and significance of sand bodies in the Northern and Central Belts, southwest Southern Uplands G.KELLINGl, P. DAVIES' & J. HOLROYD2 1 Geology Department, University of Keele, Staffs. ST5 5BG, UK 21 Blythe Road, Forsbrook, Blythe Bridge, Staffs., UK Abstract: Sedimentological and biostratigraphical data fromthe Rhinns of Galloway andadjacent areas in SW Scotland confirm that deep-water depositional systems consistently operated along, and were sourced from, the northwestern margin of an asymmetrical basin during the late Ordovician and earlySilurian, while pelagic facies accumulated simultaneously tothe SE, providing ascenario analogous to many modern trench systems. Most of the observedsedimentological anomalies, with regard to thisgeneral model, can be explained within the context of the varied styles of trench-filling depositional systems, briefly reviewed here, and the major stratigraphic and sedimentologic features can be best explained in terms of a geotectonically evolving fore-arcregion. Two main phases of development are recognized: (a) Llandeilo-late Ashgill: during this time interval the fore-arc trench region was tectonically juxtaposed against an active continental margin arc. Small- to medium-scale, SE-prograding sand-rich fans were formed within a relatively narrow trench, leading to axial diversion of the fans, initially to NE but later mainly to SW. Simultaneously a coarse volcanilithic sediment apron, flanking the arc, migrated gradually northeastwards, probably in response to relative fault displacement of the arc and trench; (b) Llandovery: during this time interval the fore-arc trench region was dominated by a variety of mainly fan-typedepositional systems which were exclusively sourced(at least until theuppermost Llandovery) from the northwestern margin.
    [Show full text]
  • Cat Herding on a Global Scale
    OneGeology-Europe – an INSPIRE testbed for semantic harmonisation of „geology“ data across Europe (WP 3) Kristine Asch and John Laxton Project deliverables • Interoperable on- shore geology spatial dataset • with ”progress • Mutilingual metadata for towards discovery harmonisation” • View services • Forerunner and “guinea • Geological pig” for the vocabulary and data implementation of specifications for INSPIRE Directive Europe • Use case studies Fact Vast amount of data hidden in the archives and hard disks in governmental organisations across Europe … Kristine Asch ©BGR.de And they are all different.. Edge matching at national boundaries? Î National boundary Î geological terms and classifications (age, lithology, tectonics ..) Î age of data (mapping campaign) Î choice of units to be mapped Î level of detail / scale Î topographical base (projection, spheroid, drainage system, ...) Î Portrayal (colours and symbols) Î Mapped border of the units Interoperability and harmonisation • Interoperability – when the data model/structure and properties to describe its parts (what GeoSciML does) is agreed – E.g. agreeing a data model will have the feature of “GeologicUnit” with properties of “age” and “lithology” • Semantic harmonisation – when the use of the same definitions and classifications to describe a concept/term is agreed – E.g. ‘clay’. The same concept can be labelled with several terms (“argilla” in Italian, “Ton” in German), but needs to have the same definition, in this case of “clay/Ton/argilla, …”): > 50% particles < 0,004 mm (Wentworth
    [Show full text]
  • A Systematic Nomenclature for Metamorphic Rocks
    A systematic nomenclature for metamorphic rocks: 1. HOW TO NAME A METAMORPHIC ROCK Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: Web version 1/4/04. Rolf Schmid1, Douglas Fettes2, Ben Harte3, Eleutheria Davis4, Jacqueline Desmons5, Hans- Joachim Meyer-Marsilius† and Jaakko Siivola6 1 Institut für Mineralogie und Petrographie, ETH-Centre, CH-8092, Zürich, Switzerland, [email protected] 2 British Geological Survey, Murchison House, West Mains Road, Edinburgh, United Kingdom, [email protected] 3 Grant Institute of Geology, Edinburgh, United Kingdom, [email protected] 4 Patission 339A, 11144 Athens, Greece 5 3, rue de Houdemont 54500, Vandoeuvre-lès-Nancy, France, [email protected] 6 Tasakalliontie 12c, 02760 Espoo, Finland ABSTRACT The usage of some common terms in metamorphic petrology has developed differently in different countries and a range of specialised rock names have been applied locally. The Subcommission on the Systematics of Metamorphic Rocks (SCMR) aims to provide systematic schemes for terminology and rock definitions that are widely acceptable and suitable for international use. This first paper explains the basic classification scheme for common metamorphic rocks proposed by the SCMR, and lays out the general principles which were used by the SCMR when defining terms for metamorphic rocks, their features, conditions of formation and processes. Subsequent papers discuss and present more detailed terminology for particular metamorphic rock groups and processes. The SCMR recognises the very wide usage of some rock names (for example, amphibolite, marble, hornfels) and the existence of many name sets related to specific types of metamorphism (for example, high P/T rocks, migmatites, impactites).
    [Show full text]
  • BCGS IC1997-03.Pdf
    For information on the contents of this document contact: Ministry of Employment and Investment Energy and Minerals Division British Columbia Geological Survey Branch 5 - 1810 Blanshard Street PO Box 9320, Stn Prov Gov't Victoria, BC, V8W 9N3 Attn: W.J. McMillan, Manager, Map ing Section Fax: 250-952-0381 [mail: [email protected] or; B. Grant, Editor, GSB Fax: 250-952-0451 E-mail : [email protected]. bc.ca Canadian Cataloguing in Publication Data I Main entry under title: Specifications and guidelines for bedrock mapping in British Columbia Includes bibliographical references: p. ISBN 0-7726-2950-1 1. Geological mapping - British Columbia. 2. Geology, Structural - British Columbia. 3. Geology - Maps - Symbols. I. British Columbia. Geological Survey Branch. Victoria British Columbia May 1997 October, 1996 TaMb Off GmQmQs Introduction . 3 Fission Track Dating Technique . 36 Part 1: Fundamental Bedrock Mapping Concepts 5 Usual Application of Geochronology . 36 Part 2: Mapping and Field Survey Procedures. 7 Materials Suitable for Dating. 36 2-1 Overview. 7 Rubidium-strontium Dating . 38 2-2 Bedrock Field Survey Databases . 10 Uranium-Lead Dating . 3 8 2-3 Quality Control, Correlation, and Map Lead Isotope Analysis . 38 Reliability . 11 Fission Track Dating . 38 Part 3: Data Representation On Bedrock Maps 13 Analytical Procedure . 39 3-1 Title Block . 13 Quaternary Dating Methods . 39 3-2 Base Map Specifications . 15 Radiocarbon Dating . 39 3-3 Reliability Diagrams . 15 Potassium-Argon Dating of Quaternary 3-4 Legend . 16 Volcanic Rocks. 40 3-5 Map Attributes . 17 Fission Track Dating . 40 3-6 Symbols. 17 Sampling . 41 3-7 Map-unit Designations .
    [Show full text]
  • Nature, Provenance and Relationships of Early Miocene Palaeovalley Fills, Northern Adana Basin, Turkey: Their Significance for Sediment-Bypassing on a Carbonate Shelf
    Turkish Journal of Earth Sciences (Turkish J. Earth Sci.), Vol. 16, 2007, pp. 181–209. Copyright ©TÜB‹TAK Nature, Provenance and Relationships of Early Miocene Palaeovalley Fills, Northern Adana Basin, Turkey: Their Significance for Sediment-Bypassing on a Carbonate Shelf A. SAM‹ DERMAN1 & KEMAL GÜRBÜZ2 1 Türkiye Petrolleri A.O., Arama Grubu, Mustafa Kemal Mahallesi, 2. Cadde, No. 86, Sö¤ütözü, TR-06100 Ankara, Turkey (E-mail: [email protected]) 2 Çukurova Üniversitesi, Jeoloji Mühendisli¤i Bölümü, Balcal›, TR-01100 Adana, Turkey Abstract: The Gildirli Formation is the oldest Neogene rock unit in the Adana Basin and was formed prior to the regionally extensive Early Miocene marine transgression. These coarse clastic red-beds provide important evidence about the causes and early phases of filling in this large trough, because the Gildirli Formation sediments fill an irregular palaeotopography carved out of Palaeozoic and Mesozoic basement rocks. Detailed study of the Gildirli Formation reveals the existence of at least two alluvial fans supplied from different source areas. A northeastern fan, exposed around Gildirli Village, was fed by streams draining an area of ophiolitic mélange, Mesozoic and older limestones, and fills an irregular palaeomorphology around and northeast of Gildirli. The southwestern fan, in the Nergizlik area, is dominated by debris flow and sheet flow rudites derived from an area of entirely carbonate bedrock. The lower part of the southwestern fan is characterised by well- bedded carbonate breccias and conglomerates that occupy deep, steep-sided palaeovalleys with approximate E–W trends (parallelling the main basin-margin), whereas higher parts of this fan are muddier and show channelised fluvial and floodplain attributes.
    [Show full text]
  • A Partial Glossary of Spanish Geological Terms Exclusive of Most Cognates
    U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY A Partial Glossary of Spanish Geological Terms Exclusive of Most Cognates by Keith R. Long Open-File Report 91-0579 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1991 Preface In recent years, almost all countries in Latin America have adopted democratic political systems and liberal economic policies. The resulting favorable investment climate has spurred a new wave of North American investment in Latin American mineral resources and has improved cooperation between geoscience organizations on both continents. The U.S. Geological Survey (USGS) has responded to the new situation through cooperative mineral resource investigations with a number of countries in Latin America. These activities are now being coordinated by the USGS's Center for Inter-American Mineral Resource Investigations (CIMRI), recently established in Tucson, Arizona. In the course of CIMRI's work, we have found a need for a compilation of Spanish geological and mining terminology that goes beyond the few Spanish-English geological dictionaries available. Even geologists who are fluent in Spanish often encounter local terminology oijerga that is unfamiliar. These terms, which have grown out of five centuries of mining tradition in Latin America, and frequently draw on native languages, usually cannot be found in standard dictionaries. There are, of course, many geological terms which can be recognized even by geologists who speak little or no Spanish.
    [Show full text]
  • Ore Bin / Oregon Geology Magazine / Journal
    Vol. 23, No. 11 THE ORE.-BIN 105 November, 1961 STA TE OF OREGON DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES Head Office: 1069 State Office Bldg., Portland 1, Oregon Telephone: CApitol 6-2161, Ext. 488 Field Offices 2033 First Street 239 S. E. "H" Street Baker Grants Pass * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ANGULAR UNCONFORMITY MARKS TRIASSIC-JURASSIC BOUNDARY IN SNAKE RIVER AREA OF NORTHEASTERN OREGON By R. F. Morrison* Introduction A well-defined angular unconformity between Triassic and Jurassic strata is exposed along the valley of the Snake River about 40 miles south of lewiston, Idaho. The Triassic rocks below the hiatus consist of poorly sorted clastics derived from a volcanic terrain; contemporaneous extrusive rocks; and well bedded, fossiliferous, impure limestones. Above the unconformity is more than 1000 feet of black shale which encompasse$ conformable beds of chert-pebble conglomerate and lenses of protoquartzite. Thick sills of quartz diorite have been intruded into the black shales. During the summer of 1961, an examination was made of the pre-Tertiary rocks which crop out along the canyon of the Snake River between Cache Creek and the mouth of the Imnaha River. The accompanying sketch map shows the approximate extent of pre-Tertiary rocks surrounding the area of interest. Further extent of pre-Tertiary rocks in northeastern Oregon has been shown by N. S. Wagner in the July 1958 issue of The Ore.-Bin. Previous Work The existence of significant exposures of pre-Tertiary rocks underlying the Columbia River basalts along the canyons of the middle Snake and lower Salmon Rivers has been known for more than 60 years.
    [Show full text]
  • Deciphering the Reservoir Rocks Lithology by Mineralogical Investigations Techniques for an Oilfield in South-West Romania
    MATEC Web of Conferences 343, 09013 (2021) https://doi.org/10.1051/matecconf/202134309013 MSE 2021 Deciphering the Reservoir Rocks Lithology by Mineralogical Investigations Techniques for an Oilfield in South-West Romania Gheorghe Branoiu1,*, Lazar Avram1, Iuliana Ghetiu1, Silvian Suditu1, and Stefan Pelin1 1Oil-Gas University of Ploiesti, Oil-Gas Engineering Faculty, 39 Bucharest Street, 100680, Ploiesti, Romania Abstract. An important element of the geological modeling of oil reservoirs is represented by determining of the mineralogical composition and rock types as part of the reservoir characterization process. In the paper we provide a comprehensive mineralogo-petrographic study based on petrographic observations and X-rays diffraction investigations made on several Miocene rock samples collected in the wells spudded in an oil field belonging to the Getic Basin. Getic Basin is a prolific petroleum province in Romania and belongs to petroleum systems of the Carpathian Foredeep. The oil exploration in the Getic Basin started more than 100 years ago and resulted in thousands of wells drilled and tens of fields discovered. The oil field is located in the Gorj County, geologically belongs to the internal zone of the Getic Basin, and is a faulted anticline with hydrocarbon accumulations in Burdigalian and Sarmatian deposits. The petrographic study led to the interpreting of the rock samples analyzed as epiclastic sedimentary rocks represented by conglomerates, breccias, sands, sandstones, claystones and marlstones, and carbonate rocks (limestones). X-rays diffraction investigations indicated the phyllosilicates (smectite and illite) as main minerals in the Sarmatian samples, while in the Burdigalian samples were found as main minerals: quartz, feldspars and carbonate minerals.
    [Show full text]
  • Gravels, Conglomerates, and Breccias
    Gravels, Conglomerates, and Breccias Introduction A gravel is an unconsolidated accumulation of rounded fragments larger than sands (Larger than 2 mm.). Material in the 2 to 4 mm. range has been termed granule gravel or very fine gravel. Siliciclastic sedimentary rocks that consist predominantly of consolidated accumulation gravel-size (>2mm) clasts are called conglomerates. The Latin-derived term rudite is also sometimes used for these rocks. Conglomerates are common rocks in stratigraphic sequences of all ages, but make up less than about one percent by weight of the total sedimentary rock mass. In contrast to sandstones, conglomerates contain a significant fraction of gravel-size particles. The percentage of gravel-size particles required to Dr. Zaid A. Malak (Dept. of Geology—Mousl University) Email ([email protected]) distinguish a conglomerate from a sandstone or mudstone (shale). Folk (1974) sets the boundary between gravel and gravelly mud or gravelly sand at 30 percent gravel. That is, he considers a deposit with as little as 30 percent gravel-size fragments to be a gravel. On the other hand, Gilbert (Williams et al., 1982) indicates that a sedimentary rock must contain more than 50 percent gravel-size fragments to be called a conglomerate. Siliciclastic sedimentary rocks that contain fewer than 50 percent gravel-size clasts (possibly fewer than 30 percent according to Folk’s usage) are conglomeratic sandstones (pebbly sandstone) or conglomeratic mudstones (pebbly mudstone). Gilbert reserves these terms for rocks with less than about 25 percent gravel-size clasts. Crowell (1957) suggested the term pebbly mudstone for any poorly sorted sedimentary rock composed of dispersed pebbles in an abundant mudstone matrix.
    [Show full text]
  • Stratigraphy and Structure of the Altar Basin of NW Sonora: Implications for the History of the Colorado River Delta and the Salton Trough
    Revista Mexicana de Ciencias Geológicas,Stratigraphy 2006, v. and 23, structurenúm, 1, 2006, of the p. Altar 1-22 basin of NW Sonora 1 Stratigraphy and structure of the Altar basin of NW Sonora: Implications for the history of the Colorado River delta and the Salton trough Martín Pacheco1, Arturo Martín-Barajas1,*, Wilfred Elders2, Juan Manuel Espinosa-Cardeña1, Javier Helenes1, and Alberto Segura3 1 División de Ciencias de la Tierra, CICESE, Km 107 Carr. Tijuana-Ensenada, Ensenada, Baja California, Mexico. 2 Department of Earth Sciences, University of California, Riverside, CA 92521, USA. 3Activo Regional de Exploración, Región Norte, PEMEX, Poza Rica, Veracruz, Mexico. [email protected] ABSTRACT The Altar basin in northwestern Sonora, Mexico, is a subsidiary basin forming a now inactive part of the Colorado River delta. Its sedimentary record illustrates how the delta prograded in the last 4–5 Ma over a late Miocene, structurally distinct, marine basin at the northern end of the Gulf of California. Our interpretation of outcrop data, and data from seven exploratory wells, six analog seismic lines of Petróleos Mexicanos (PEMEX), and magnetic and gravity surveys from various sources indicates the existence of three sedimentary sequences, A, B, and C, which can be correlated at regional scale and have a thickness >5 km at the basin depocenter. The lower sedimentary sequence A is a shale unit representing open marine conditions (outer neritic). It grades into a thick sequence of interstratifi ed mudstone, siltstone, and sandstone (sequence B), which grades in turn into poorly consolidated sand (sequence C). Extensive outcrops of a sandy, cut and fi ll succession exposed along the coast of Sonora are consistent with sequences B and C being the sub-aqueous and the sub-aereal parts of the delta, respectively.
    [Show full text]
  • Composition and Provenance of the Rudite and Arenite Facies in Aforeland Basin, Northern Marchean Apennines, Italy
    Composition and provenance of the rudite and arenite facies in aforeland basin, northern Marchean Apennines, Italy N. (2APLANO Istituto di Ceologia Applicata, Universitá di Urbino. ViaMuzio Odd¡, 14. 61029 Urbino, Italy. ABSTRACT Ibe Montecalvo in Foglia basin (Northern Marche, Italy) is infilíed by rudite and arenite deposits. The rudite facies (conglomerates) are mainly represented by carbonate, chert, and sandstone clasts while the arenite facies is characterized by a quartzolithic or fedspadiic litharenite petrofacies (mean values: Q 47, F,8, L35). This is characterized by a large number of lidiic fragments reflecting a local provenance from the sedimentary cover of the Marchean Apennines. Morphometric and compositional aualyses suggest diat the rudites, mostly made up of pebble-to-cobble-sized clasts, derived from the erosion of the «Ligurid» sequences to the northwest of the basin. They were elaborated in fluvio-torrential systems under temperate-warm climate conditions. Afterwards, during relative sealevel lowstauds, diese were eroded, cannibalized and resedimented into fasis or aprons confined to the narrow sub-basins of the Adriatic Foredeep. Textural data of the arenites shaw a premature diagenesis, characterized by a rapid formation of carbonate cement, which inhibited the mechanical compaction of sediments. Key words: Northem Marchean Apennines, Pliocene basin, cannibalized fandelta deposits. rudite and arenite composition, provenance. paleogeography. Cuadernosde Geología Ibérica N.’> 15, 185-207. Madrid, 1991. Edit. Universidad Complutense. 186 N. Capuano RESUMEN El relleno de la cuenca pliocena de Montecalvo in Foglia (Marche septentrional, Italia) se realizó por depósitos rudíticos y areníticos. Las facies rudíticas (conglomerados) están formadas por clastos calcáreos, pedernalinos (cuarcitícos), y de areniscas mientras que las facies areniticas (areniscas) están constituidas por una sola petrofacies: cuarzolítica o litareniscas feldespáticas (Q 47, F1~, L35).
    [Show full text]