ORIGIN OF THE GAS-CONDENSATE POOLS IN NORTHWEST SIBERIAN

Abstract

Zone of oil and gas accumulation encompassing the Nadym-Pur, Pur-Tzov, Gydansk and Yamal oil and gas regions has been established in the northern part of West Siberia. A characteristic feature of this zone is the development of a thick (up to 2000 m) Cretaceous Neocomian-Cenomanian complex, with which more than 95 percent of the gas and gas-condensate resources of West Siberia are associated. The formation of the GC pools was associated with the formation of the natural-gas systems by transformation of organic matter in the host rocks. In the scheme of the vertical HC zoning in northern West Siberia, a low-temperature zone of generation of primary condensates of naphthene composition is distinguished that is generally related to the coal measures of the Ust'-Taz group. The formation of the upper (low-temperature) zone of generation of the 'primary' condensates in northern West Siberia is an exception. The northern regions of West Siberia should be considered highly promising for the discovery of liquid HC pools.