Thaddeus S. Dyman¹, G.F. Ulmishek¹, V.A. Litinsky²
(1) U.S. Geological Survey, Denver, CO
(2) Consultant, Aurora, CO

Abstract: Geology and natural gas potential of deep sedimentary basins in the Former Soviet Union

Sedimentary basins of the former Soviet Union (FSU) are among the deepest in the world with depths to basement exceeding 20 km in the North Caspian, South Caspian, and South Barents basins. Deep basins (those with sedimentary rocks exceeding 4.5 km) occur in both offshore and onshore areas of the FSU and extend from the Arctic Shelf in the north, to the Sea of Okhotsh and the Kamchatka Peninsula in the east, to the Central Asian republics in the south, and to Poland and Romania in the west. These basins formed in a wide variety of plate-tectonic regimes and include rift basins (Dnieper-Donets basin), Foreland basins (Volga-Ural and Timan-Pechora basins), and passive margins (Afghan-Tajik basin). Some of these basins contain deep gas fields. Other basis have not been deeply drilled, but the potential for future discoveries remains high. For many deep basins of the FSU, little or no geologic and production data are available—particularly for those basins in the Arctic offshore and Russian Far East.

Six basins (Dnieper-Donets, Vilyuy, North Caspian, Middle Caspian, South Caspian, and Amu-Darya basins) have the greatest potential for deep undiscovered gas resources based on available data. For each basin, we present the location, tectonic and sedimentary history, principal source and reservoir rocks, petroleum systems, trapping mechanisms, and potential for deep production.

Source and reservoir rocks range in age from Proterozoic to Tertiary. Major source rocks include the Devonian Domanik Formation of the North Caspian and Timan-Pechora basins and siliceous shales of the Oligocene to lower Miocene Maykop Series of the South Caspian basin. Both carbonate and clastic reservoirs are abundant. Reservoirs are predominantly clastic in the Vilyuy, Dnieper-Donets, and South Caspian basins, whereas the North Caspian basin contains predominantly carbonate reservoirs.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana