Prospects of Oil and Gas Presence in the Middle Caspian According to the Results of Basin Modeling

Postnova, Elena V., I. V. Oreshkin, O. I. Merkulov, V. V. Gontarev, M. A. Potapov, NVNI­IGG, Saratov, Russia

The study of 1995-2003 years has resulted in electronic geologic model of the Caspian Sea water area, which allows to realize the methods of 3D basin modeling by means of the TEMIS 3D program complex (IFP-BeicipFranlab).

Modeling results make it possible to evaluate the total initial HC reserves in the Middle Caspian part studied and in the adjacent land area as 12-14 billion tons of conventional fuel, 5-7 billion tons of c.f. in the Caspian water area included. Over 90% of the reserves occur in the Jurassic-Cretaceous complexes. The Jurassic-Triassic deposits dominate in HC generation and emigration scale, with about 80% of generated HC. The modeling results show, that by the end of the Cretaceous, numerous oil and gas-oil accumulations have already been present in the Jurassic beds of the Middle Caspian Sea.

In the Maikopian, intensive formation of the Tersko-Caspian Trough resulted in increased angle of regional gradient of the surface of the Cretaceous, Jurassic and Permian-Triassic deposits to the south-east of the Karpinsko-Mangyshlak system. The increase of the regional gradient was accompanied by destruction of numerous structur­al paleotraps and oil paleodeposits in this zone. The undestroyed traps reduced in vol­umes. Similar effect is illustrated by the case of the paleotrap system from the Khvalynsk paleorampart.