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A Sibneft affiliate is drilling a wildcat in search of crude oil in the eastern Anadyr basin on a nearshore island in southern Anadyr Gulf.
Another Sibneft project is to involve development of gas identified in an onshore field to replace coal at a power plant in Anadyr. Sibneft and OAO Yukos, Moscow, are to form a 50-50 joint venture in third quarter 2001 to reprocess seismic data from the shelves of the Chukotka and East Siberian seas. Later they will acquire more seismic data, perhaps as soon as late 2001, and might eventually drill wildcats offshore, Sibneft said.
The geological structure of the East Siberian Sea and Chukotka Sea basins is believed to be similar to that of Alaska's North Slope, Sibneft said.
High-potential deeper water basins of the Chukchi Sea do not appear to be on Sibneft's scope Anadyr operations Sibneft said its acquisition of licenses to onshore blocks in the Anadyr basin last April would help the company achieve its goal of expanding its upstream operations beyond its home base in Noyabrsk, western Siberia.
Affiliate Sibneft-Chukotka has drilled about half way to projected TD of 3,100 m at its first Chukotka well, on Molchalivy Island 150 km southeast of Anadyr (Fig. 1). The unexplored Lagunny depression of the eastern Anadyr basin contains large thicknesses of Tertiary and Cretaceous aged formations. Sibneft said earlier that the 950 sq km Lagunny acreage could harbor 275 million bbl of reserves. Sibneft is preparing to develop West Ozyornoye dry gas field on the 70 sq km block of the same name. It would drill four wells to develop an estimated 415 bcf of C1 and C2 reserves and lay a 100 km pipeline to a converted coal-fired power station at Anadyr, population 9,000. The coal reserves are depleted and production costs are high. Contractor selection and engineering studies are on tap this year, and drilling and pipelaying would begin in 2002. Production would start in 2003 and reach a plateau of 12.5 MMcfd in the second year. Sibneft said West Ozyornoye field has not been produced previously and that none of the old Soviet wells in the field is in condition to contribute production. The 4,070 sq km Telekayskoye block contains Upper Telekayskoye, Upper Echinskoye, and Olkhovoye (not shown) fields. Sibneft said the Telekayskoye block contains reserves of 20 million bbl of oil and 71 bcf of gas and the West Ozyornoye block has 176 bcf of gas. Sibneft holds a fourth block that incorporates Uglovoye field in the Khatyr basin near the coastal town of Meynypilgyno but is not developing it for now. All of the fields were discovered during the Soviet era.
Sibneft and Yukos will undertake initial exploration studies in 90 m of water or less in the gulf southeast of Anadyr and off the north coast of Chukotka, but Sibneft declined to be more specific about target areas. Sibneft acknowledges that conditions in the deeper water parts of the Arctic Ocean would be far more challenging. Russian literature indicates that unexplored parts of Russia's northern Chukchi, or Chukotka, Sea could contain oil resources that rival those of the Alaska North Slope. Russian geoscientists have written that the area of the barely explored Russian part of the Chukchi Sea favorable to hydrocarbons covers 340,000 sq km. The Chukchi Sea is part of the Arctic Ocean north of eastern Siberia and northwest of Alaska.
D.S. Orudzheva et al., writing in Geologiya Nefti I Gaza in 1999, said density of resources in place could exceed 30,000 tons of oil equivalent/sq km in the North Chukchi basin and 5,000 tons/sq km in the South Chukchi basin.
The areas could hold 35 to 105 billion bbl of oil equivalent in place, says the article by Orudzheva et al. summarized in English in the quarterly journal Petroleum Geology, McLean, Va. "A more reliable assessment is possible only after the main local structures of the North Chukchi basin have been mapped," they wrote. Lying entirely above the Arctic Circle, the basins could be home to fields that require complex, hostile-environment development plans.The area has no pipelines and is well north of Russia's only existing offshore hydrocarbon producing field, the Astokh portion of Piltun-Astokhskoye oil and gas field in the Sea of Okhotsk off Sakhalin Island (OGJ, July 19, 1999, p. 44).
The passive-margin sediments of the North Chukchi basin are more than 8 km thick and are highly favorable for petroleum, Orudzheva et al. wrote. Only small gas pools are expected in the South Chukchi basin, where the sedimentary section is relatively thin at 2 to occasionally 4 km thick.
The North Chukchi basin is of interest for hydrocarbons even though it is 400-600 km off the Chukchi Peninsula.
|North Chukchi should have Paleozoic, Permian-Mesozoic, and Upper Cretaceous-Cenozoic petroleum systems on the basis of the structure of the sedimentary cover and by analogy with the Alaska North Slope, Orudzheva et al. wrote (Fig. 2). They said the Chukchi Sea has high potential for discovery of oil and gas in the North Chukchi basin in Permian, Triassic, Jurassic, Cretaceous, and Paleogene formations and for gas in the South Chukchi basin in Cretaceous, Paleogene, and Miocene zones. Separating the two Chukchi basins is the Gerald-Wrangel zone of highs, which is characterized by intensive faulting and less thickness of the sedimentary cover.|