Exploring for Mammoths

EXPLORATION Exploring for mammoths The sedimentary basins offshore West-Greenland cover an area comparable to the entire North Sea.Six dry wells so far can therefore not be sufficient reason for writing off the possibility of finding oil and gas here in the future.Furthermore,geologists can now demonstrate the probable presence of prolific source rocks, good reservoirs and enormous structures.

Elephants do not enjoy a cold climate. Offshore West-Greenland the search is therefore focused on ``mammoths´´. New data and solid geological studies confirm GEUS´s belief that they can be found. © GEUS Photo: Halfdan Carstens

Everyone knows that Greenland has some magnificent scenery. But – and this is serious for those concerned with trying to get the oil industry interested in prospecting – the belief is widespread that icebergs float around everywhere along the coast. The fact is that ocean currents flow in such a way that the west coast of Greenland south of Disko (70ºN) is for the most part iceberg-free. Instead the majority of these white monsters drift southwards along the east coast of Canada (Baffin Island). EXPLORATION

Viking – Central graben system

Halfdan Carstens of the North S ea at same scale

GEUS

espite 6 dry wells and limited inte-

Sisimiut

Davis Strait Davis

rest from the oil industry the search

for oil and gas in the large areas west

of Greenland will continue. Optimism is

Tasiilaq

greater than for some time past due to

several promising news. On the other hand

Nuuk

geologists struggle to explain a number of

"home truths".

The myths

– We must work to remove some esta-

blished myths. Three of these persist: the

Qaqortoq

Labrador difficult ice conditions, a lack of suitable Sea 250 km source rocks and the presence of oceanic crust between Greenland and Baffin Island, It is easy to be taken in by the mere scale of things since Greenland is so large and unknown. But the fact is says Flemming G. Christiansen, leader of that the sediment basins outside the West-Greenland coast cover an area about as extensive as the North the stratigraphic department in the Geolo- Sea Rift. gical Survey of Denmark and Greenland (GEUS).He is also responsible for the geolo-

GEUS gical work which the institution is carrying © out in the large sedimentary basins offshore West-Greenland.This takes place in colla- boration with the Bureau of Mineral and Petroleum, Government of Greenland (“Råstoffdirektoratet”) in Greenland’s own internal administration (“Hjemmestyre”) responsible for licensing. One of the myths which has survived is that oceanic crust is widespread between Greenland and Canada. – Hence, without knowledge of the new research results, it is natural to choose other areas for exploration. But we now have data which show cle- arly that continental crust exists between

62ºN and 68ºN, claims Christiansen. – Seis- GEUS © mic data showing 6 seconds with sedi- ments and drill-holes deep into the Creta- ceous should be enough to convince most people, he maintains. Former geological misconceptions are therefore in the process of losing ground. – Ten years ago it was much more difficult to promote the continental shelf offshore West-Greenland, but today we have good news to offer. The explanation for this is that we now have much more data and several geological studies which, collecti- Research over recent years has proved once and for all that the shelf offshore West-Greenland lies on conti- vely, show that the sediment basins have a nental crust. Experts, however, are slow to accept this knowledge. GEUS struggles therefore with the fact completely different character than was that several oil companies give only low priority to the area believing it to lie on oceanic crust. thought in the 70´s and 80´s when the myths became established, says Christian- sen. Finds of sediment and oil at least in commercial quantities. One of – The new insight is the result of the stra- The first phase in the search for oil and the wells, Kangâmiut-1, detected gas under tegy which we have pursued.The efforts of gas offshore the coast of West-Greenland high pressure but testing yielded only dril- the Bureau of Mineral and Petroleum and began in the 1970´s. Six groups of oil com- ling fluid. – The results from drilling, comb- GEUS have, quite simply, paid off, he main- panies, Amoco, Arco, Chevron, Mobil, Total ined with poor quality seismic data (which tains. and Ultramar, took out licences. Five wells formed the basis for the geological were drilled without any show of oil or gas, models), caused the oil industry to declare

16 GEO ExPro June 2004 the area to be totally uninteresting, says Generalised stratigraphy of southern West Greenland Christiansen. These conclusions remained unchal- GEUS

lenged until The Geological Survey of Gre- © enland (GGU, now a part of GEUS) began a re-study of the area. – A project involving reprocessing the old seismic data was of crucial significance, relates Flemming G. Christiansen. Large, faulted blocks now became evident in deep water where oceanic crust was formerly thought to occur. Now it could be established that continental crust covered a much larger area in the deep sea areas than previously supposed. Therefore it was necessary to re-evaluate the possibility of finding hydrocarbons in these areas. At the same time oil seepages were detected on the surface of volcanic rocks on the Nuussuaq peninsula. A well drilled Drilling has given quite down to 448 m showed oil to be present a good picture of the throughout the whole volcanic rock stratigraphy offshore sequence. The subsequent prospecting West-Greenland. well drilled on land in 1996 by a Canadian Reservoir rocks are company was dry, but later investigations proven at several indicated that it penetrated sandstones levels, and Statoil´s with oil shows. A big programme involving drillhole in particular is collection and detailed analyses of oil sam- interesting because it ples has shown that at least two source reveals the presence of sandstones in Upper rocks are present and these can have wide Cretaceous rocks. regional distributions. One is of Upper Cre- taceous age (Cenomenian/Turonian) and the other of Paleocene age. – There is no doubt that the discovery of this oil is a enland, resulted initially in additional and (Santonian) sandstones. Their existence strong contributory reason for the return of more modern seismic being carried out. It was not previously known, and they have the oil industry to Greenland. Earlier, the so happened that the absolute last line of given us a new target which, with seismic absence of source rocks was the most the seismic programme from 1992 showed data, we have tried to extend across the negative parameter in risk assessment stu- the presence of fault blocks and flat spots whole basin, says Christiansen. dies, says Christiansen. which indicated the possible presence of – Statoil had hopes of finding large The re-processed seismic data, which hydrocarbons in the structures. Four years amounts of gas in the Fylla licence area. revealed the possible presence of thick later Statoil together with Phillips, Dopas This was based on seismic evidence which sedimentary packages offshore West-Gre- and Nunaoil took out a licence based on showed what we called a "cross-cutting" these data. Oil activity was now in full reflector (CCR). In advance, 8-9 different swing – for the second time in the history interpretations for the CCR were conside- of Greenland. red, of which one was that it could repre-

GEUS sent a gas/water contact, partly because it © A dry well coincided with the mapped spill point of – Statoil was very optimistic, mostly on several structures.The potential volumes of account of a prominent crosscutting reflec- hydrocarbons were so large that the gas tor (flatspot) which could indicate the pre- alone could be of interest for LNG, says sence of hydrocarbons. Disappointment Ånon Spinnangr in Statoil who was respon- was therefore great when, after drilling sible for Statoil`s licence. 2000 m (Qulleq 1), it became apparent that – The well showed no sign of source the flat spot was due to diagenetic chang- rocks or of hydrocarbons. Based on drilling es related to temperature and lithology in a results and regional considerations Statoil thick shale package (transition from opal nevertheless believe that this well does not CT to microquartz). In a regional context, in any way detract from the possibility of however, the well was very important. It finding hydrocarbons in other parts of the It is not unusual with oil shows like this on the showed good reservoir quality rocks (poro- shelf area off West-Greenland. The presen- Nuussuaq Peninsula and Disko Island. sity over 20%) in the Upper Cretaceous ce of source rocks at the right levels will,

GEO ExPro June 2004 17 EXPLORATION

Based on geological studies and subsesquent discussions with both oil compnies and seismic companies, four areas have been selected to be included in the third licensing round. They each differ from each other in structural style, petroleum systems and operating conditions. Common to all of them, however, is giant size leads with potentially more than one million barrels of recoverable oil. Area 1 – Lady Franklin Basin – A seismic line through cover 10,500 km2 with water depth the Fylla structure ranging from 700-2000 m. showing the flat spot Area 2 – Kangaamiut Ridge and one hoped for but per- 2 haps did not comple- Basin – cover some 4900 km with tely believe should fairly shallow water depth from 200- represent the border 600 m. between gas and oil or Area 3 – Ikermiut Ridge and Basin between gas and – is with 7000 km2 somewhat bigger water. but with similar water depth ranging from 150-500 m. meanwhile, still be a major factor of uncer- interest, explains Flemming who himself tainty. This is the view of Ånon Spinnangr has wide experience from Greenland after Area 4 – Paamiut Basin – is with 2 who has wide experience in the search for more than 15 summers in the field.We have 11,200 km the largest area. Water oil in many parts of the world. chosen to focus the investigations on pro- depth is from shallow (150 m) to After a new licence round in 2002 the spects we believe to have a very good deep (1750 m). Canadian company EnCana was awarded a potential, he says. 2D seismic is available inall four 2 licence with an area of 3985 km (some 50 areas, while 3D seismic has not yet km north of Statoil’s well). No wells have Will only be looking for been acquired. been drilled yet. mammoths A new licence round has recently been announced in Copenhagen and Houston. GEUS, in close cooperation with the Substantially more data and knowledge is Bureau of Mineral and Petroleum, is now available this time enabling the companies pursuing another strategy than previously

to focus better. in an attempt to attract the oil industry to © GEUS – We have been in contact with both the new ventures on the Greenland Shelf. – We oil companies and seismic companies have worked hard to gain attention, says regarding the areas which should be given Christiansen,by giving talks at conferences, priority. The conclusion was that smaller writing scientific articles, visiting the oil areas should be targeted. In the previous companies and inviting them to Denmark. licensing rounds the whole area was open, The geological work has been concen- but the companies had too little time. We trated on a regional mapping of two possi- have now built on the interest shown at ble reservoir formations, one in the Paleo- that time, and since the database was not cene and one in the Cretaceous, the sand- good enough more seismic by TGS NOPEC stones of which first became interesting and Fugro is now available. Our impression after Statoil´s well. is that industry prefers this way of doing – The oil industry only looks for elep- things, claims Christiansen. hants – or mammoths – and therefore we GEUS has selected four areas which have ignored all structures less than 100 cover 32,000 km2 (equivalent to more than km2 and concentrating on those larger 50 North Sea blocks). We have done the than 400 km2.Structures which lie at less first screening based on principles favou- than 1000 m below sealevel have also been red by those companies which have shown excluded from the map. We have also

18 GEO ExPro June 2004 excluded prospects which lie far from sup- GEUS posed mature source rocks or which are in- © adequately mapped, explains Christiansen. – Nevertheless, four areas remain as well as a large number of structures which qua- lify as hunting grounds in which mammoths can be found, he says. Faith in source and reservoir rocks

- I am worried about the source rocks west of Greenland, says Thomas Ahlbrandt of the United States Geological Survey (USGS) in Denver. As World Energy Project Chief for the large-scale worldwide resour- ce assessment run by the USGS since 1995 he is qualified to express his opinion. Flemming G. Christiansen understands Ahlbrant´s concern, but he claims there are several indications that oil and gas have been generated in the basin. – During drilling there have been good gas readings, oil is proven in drill cores, and we have a number of field observations where oil emerges from the rocks, says Christiansen. In a wider regional perspective gas occurrences in Paleocene sandstones on the Canadian shelf are worthy of mention. GEUS has documented onshore seeps in the Disko-Nuussuaq area (for location, compare lower map on page 16). Seepage offshore the Disko-Nuussuaq area is also strongly indicated by a satellite seep detec- tion study carried out for Nunaoil.The possibility of offshore seepage is furthermore indicated by several amplitude anomalies and shallow gas related features observed in the seismic data from the area with satellite slick observations. - Our extensive scientific investigations have now opened up the possibility that we have both Jurassic and Cretaceous (Cenomanian) source rocks and analyses indicate that the latter are the more promising. They can be correlated with similar rocks across much of North America and it is most likely that a marine connection bet- Rumors concerning the presence of oil on Nuussuaq are very old and in 1992 small ween Greenland and Canada existed at amounts of oil were found in volcanic rocks.A drill-hole put down to a depth of 448 m that time. - The seismic data also show many signs the following year established it to be a genuine show.This was enough to encourage of an active petroleum system in the basin. commercial investigation and a small Canadian company was awarded a license.They There are many examples of possible carried out core drilling down to 900 m,geophysical surveys and a 3 km deep well.The hydrocarbon leakages in the form of gas license expired before commercial quantities of hydrocarbons could be proved.Subse- pipes, pock marks, flat spots, bright spots quent analyses,however,indicate that thick sandstones should have been tested. and "smeared seismic" which indicates According to GEUS,Nuussuaq is still an area in need of further investigation.Later shallow gas. We hope to get samples of oil and gas from the sea floor in the years to mapping has registered 100 oil shows along the Disko coast.The picture shows drill- come for analysis in order to establish their hole GRO#3 from 1996 on Nuussuaq.Disko island lies on the opposite side of Vaigat- composition, according to Christiansen. sundet. EXPLORATION

There is, however, no doubt that reservoir rocks exist. There are many good ana- © GEUS logues on land,and in Cretaceous and Pale- Licensing history ocene time huge quantities of sand were poured into the basins. – Reservoir is not a The continental shelf offshore West-Gre- problem. There are many possibilities enland is divided into three areas for licensing purposes. In the north and south oil throughout the Upper Cretaceous sequen- companies can apply for large areas ce and upwards, says Christiansen. throughout most of the year. These are But Jurassic reservoir rocks are also a designated "open door areas". In the midd- possibility even though they have not yet le, between 63ºN and 68ºN, licences are been found in drill cores. The seismic data awarded for specific areas, each with its indicate the possible presence of Jurassic own round of licensing. rocks in the basins. A programme of shal- There have been two licensing rounds so low seismic, sampling and later drilling is far in the course of the last 10 years. Three planned to demonstrate this in the coming licences have been awarded. The third years. – It is not yet proved that these rocks round is now under way. Phillips Petroleum (now ConocoPhillips) occur in the basin but we have good indi- Flemming G. Christiansen in GEUS has many field and Statoil were operators with one licence cations, all geological, which point in this seasons on Greenland. each following the first round. Only Statoil direction, according to Christiansen. drilled and despite the fact that the well was dry it supplied a lot of valuable geological Applied Science the seismic investigations have revealed information. It proved the existence of Flemming Christiansen emphasizes in regarding sedimentary thicknesses, regio- sandstones of Cretaceous age which up to particular the increased knowledge which nal tectonics and sea floor spreading toget- then were unknown from the continental her with improved understanding of the shelf. source rock problem. These breakthroughs The second licensing round closed in have led to new licensing awards being July 2002 and following negotiations the © GEUS made, the first since the middle 70’s. – The- independent oil company EnCana was awarded a license with Nunaoil (carried re is no doubt that improved knowledge partner) in the exploration phase. The Cre- concerning possible source rocks has been taceous sandstone found in Statoil´s well an important factor for the oil industry and was to a large extent decisive for generating explains their renewed interest, he says. interest in this block, but it also gives sup- – Prospecting for oil and gas offshore port to the belief that source rocks can exist West-Greenland was for a long time rese- in the Cretaceous (Cenomanian-Turonian). arch-based, says Christiansen. He bases this The third licensing was officially opened on the two big breakthroughs GEUS achie- April 1st and will be closed October 1st. ved in understanding the hydrocarbon potential latent in the sediment basins (thick sedimentary packages and source rocks).This is due to well focused and good research carried out over many years. This, 71°N

in turn, convinced the authorities, and in a d

the next instance the oil industry, to invest a Disko

hC IlIulisat t

in areas with considerable risk, but also i

r with large potential. e

rd 68°N

After the two first licensing rounds it was B Hellefisk-1

nevertheless necessary to change tactics. – Sisimiut-West licence We now say that oil search is strategically Ikermiut-1 Sisimiut determined.The reason for this is that befo- Kangâmiut-1 Nukik-1 re the next round of licensing in 2004 we Nukik-2 have improved the working atmosphere by emphasizing close cooperation and a bet- Fylla licence ter dialogue with the oil industry.This time Qulleq-1 Nuuk

we believe it will give results since interest 63°N seems to have been aroused. Flemming G Christiansen envisages GEUS believes firmly that there can be a source many exciting years ahead with scientific rock in the Lower Cretaceous. Both local and regio- Greenland nal observations support this. The map shows whe- research closely tied to the intensive search

re it can be mature (dark green colour). All four for oil and gas.As a scientist with a focus on 60°N new areas included in the next licensing round lie applied aspects of knowledge he cannot 250 km where the source rock is thought to be mature. ask for more.

20 GEO ExPro June 2004