The West Siberian Basin Province is one of the largest sedimentary basins in the world, with an area of 2.6 million square kilometers, and the basin ranks first in the world with more than 400 billion barrels of oil-equivalent discovered petroleum. For the 2008 Circum-Arctic Resource Appraisal, the U.S. Geological Survey defined a Northern West Siberian Mesozoic Composite Total Petroleum System (TPS) and two geologic assessment unit (AUs) within this composite TPS that are north or partially north of the Arctic Circle. The Northern West Siberian Onshore Gas AU was defined to encompass all potential structures, traps, and reservoirs in the onshore part of the Composite TPS. The South Kara Sea Offshore AU was defined to include all potential structures, traps, and reservoirs within the thick sedimentary section that extends offshore from the Northern West Siberian Onshore Gas AU.
For the Northern West Siberian Mesozoic Composite TPS, the total mean estimates for undiscovered conventional oil and gas resources are 4.1 billion barrels of oil (BBO), 663 trillion cubic feet of gas (TCFG), and 20.7 billion barrels of natural gas liquids (BBNGL). For areas of the AUs north of the Arctic Circle in the West Siberian Basin Province, the total mean estimates for undiscovered conventional resources are 3.7 BBO, 651 TCFG, and 20.3 BBNGL. The total mean estimates for undiscovered oil and gas north of the Arctic Circle for the Northern West Siberian Onshore Gas AU are 1.2 BBO, 29.3 TCFG, and 0.85 BBNGL. Mean estimates for the South Kara Sea Offshore AU are 2.5 BBO, 622.2 TCFG, and 19.5 BBNGL. The estimate for undiscovered conventional gas resources for the South Kara Sea Offshore AU is the most of any AU in the Circum-Arctic study.
