Several large tectonic features have been mapped in the south of the shelf of the Kara Sea. These include the Rusanov-Leningrad zone of highs, Skuratov swell, Obruchev high, offshore part of Nurmin swell, Matusevicha-Vil'kits saddle, Yavay and Preobrazhen swells, and the Middle Yamal swell. This region is a continuation of the West Siberian oil-gas province, and the structures are characterized by a great range in oil-gas productivity from the Jurassic to the Cenomanian inclusively.
Commercial productivity has been established in the Rusanov- Leningrad zone of highs and the Nurmin swell, where gas-condensate fields have been discovered at Rusanov and Leningrad (Cenomanian- Aptian) and also at Kharasavey and Kruzenshtern (Cenomanian and Upper Jurassic). A characteristic feature of the local structures of the Rusanov-Leningrad zone of highs, Skuratov swell, and Obruchev high is the syn-sedimentational nature of their development. This raises the possibility for discovery not only of gas and gas-condensate pools but also oil pools, particularly in the Neocomian and Jurassic. All this indicates high favorability for this shelf.
The areas of the Ob and Taz Gulfs are similar in geology to the adjacent onshore areas. Numerous gas and gas-condensate fields have been discovered along the shores of these gulfs. Present there are structural traps of the same type and genesis as those of the adjacent onshore, and seals and reservoirs are the same. More than 25 favorable structures have been mapped in the Ob and Taz Gulfs, and commercial gas has been discovered in 7 onshore. Commercial gas has already been found in Cenomanian sediments in Severo-Kamennomys and Kamennomys-more fields in the Ob Gulf. A total of 6107 km of 2D seismic surveys have been carried out on Aderpayutin, Antipayutin, Chugor'yakhin, and Ob structures.
Oil and gas-condensate pools are expected to be found on the Kara shelf in Lower-Middle Jurassic, Vasyugan (Upper Jurassic), Achimov, and Neocomian complexes. In contrast to the onshore areas the oil on the shelf may have wider stratigraphic range into the Aptian and Albian-Cenomanian sediments. Ages of the regional seals are Late Jurassic-Valanginian and early Albian-Turonian- Campanian. The oil is expected to be medium density, low in sulfur, low in tar, and high in paraffin.
The most favorable targets in the south of the Kara Sea are the Skuratov swell, Obruchev high, Matusevicha-Vil'kits saddle, and Litke swell.
Taken from Sakharov, 2002; digested in Petroleum Geology,
Vol. 37 (Planned annual volume); four maps showing oil-gas
prospects.
Copyright 2003 James Clarke. You are encouraged to print out
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