Abstract: The South Caspian Oil and Gas Basin Reservoirs, Formation and Their Oil and Gas Saturation

Dr. Akif Narimanov

The South Caspian oil and gas bearing basin (SCB) developed in the middle part of the Alpine-Himalayan foldbelt within the smaller province of the South Caspian Sea. The thickness of sediment is between 22-25 kilometers, with 7-8 kilometers within the principle hydrocarbon bearing Pliocene deposits.

Pliocene strata contain thick sequences of sandstone reservoirs and the bulk of the known hydrocarbon accumulations. Pliocene strata do not appear to be hydrocarbon source strata, but contain the thickest reservoir packages and remain the dominant exploration target in the basin. Future exploration will continue to concentrate on Pliocene reservoirs, most of which are at depths in excess of 5000 meters in the SCB.

Investigations of over 1000 core samples from the Pereryva and equivalent suites confirm a chiefly quartz arenite composition (70-85% of the samples). Low carbonate cement (7-12% per sample) and fairly low clay content (22-27% per sample), suggesting good reservoir properties will exist at depths, perhaps exceeding 6 kilometers.

Favorable and unusual reservoir properties, burial history, thermobaric conditions, vertical fluid migration and favorable tectonics suggest that significant new reserves of both gas and oil will be found within the SCB.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994