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Geology and Petroleum Resources of West Siberian Basin, USSR

James W. Clarke, H. Douglas Klemme, James A. Peterson

The West Siberian basin occupies an area of approximately 3.3 million km2 (1.3 million mi2) in northwestern Siberia east of the Ural Mountains. Thickness of the Phanerozoic sedimentary cover ranges from approximately 3-5 km (10,000-15,000 ft) in the central area of the basin, to 8-12 km (25,000-40,000 ft) in the northern part. The basin is filled with approximately 10 million km3 (2.4 million mi3) of Mesozoic-Cenozoic clastic sedimentary rocks ranging in thickness from 3-4 km (10,000-13,000 ft) in the central area to 6-9 km (20,000-30,000 ft) in the north.

The basement in the basin is Precambrian and Precambrian-Paleozoic granitic rocks and in places is highly metamorphosed Paleozoic sedimentary rocks. carbonate and clastic rocks are only lightly metamorphosed and are targets for petroleum exploration. The Mesozoic-Cenozoic sedimentary basin fill was initiated in the northern part of the basin during the Triassic. By the Late Jurassic, marine clastic deposition had spread throughout the basin, and the basin configuration was established for the remainder of geologic time. Cretaceous and lower Tertiary rocks are primarily shallow marine shelf, coastal plain, and lowland clastic deposits formed during several transgressive-regressive phases.

Major oil accumulations, mainly in Lower Cretaceous and Jurassic sandstone reservoirs, are located in the central and west-central parts of the basin. The largest reserves of natural gas in the world are located in the northern part of the basin, primarily in Upper Cretaceous (Cenomanian) sandstone reservoirs. In 1981, estimated cumulative production from the basin was approximately 10 billion bbl of oil. Estimated mean undiscovered resources (1981) are approximately 80 billion bbl of oil and 700 tcf of gas.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.