Geological and Geochemical Model of Formation of Oil and Gas Accumulations in the South Caspian Basin
NARIMANOV, AKIF A., no affiliation listed.
The South Caspian Sea, Azerbaijan, has been a major petroleum producer since 1848 and is still one of the premier prospective areas for oil and gas in the Soviet Union. Many years of research studies suggest an area of increased prospectivity in the deeper part of the Caspian Sea.
Geologic history recorded that a trough developed during the Mesozoic through the Tertiary. The sedimentary sequence is up to 23 km thick. The Pliocene sequence is the major proven productive and prospective interval. Multiple stages of active sedimentation and tectonism took place starting in the early Pliocene and ending in the late Pliocene.
Traps were formed and destroyed during the early to late Pliocene. The final tectonic events during the late Pliocene trapped the remigrated oil. Gas and gas condensate probably are within the lower reaches of the basin. Because of the rapid deposition, mud volcanoes were also active. Many are sill active today and can be noted in proximity to hydrocarbon deposits.
Rapid subsidence and deposition, an anomalously low geothermal regime, and a low maturity of sampled organic matter from the Pliocene section leads to the hypothesis of hydrocarbon generation at depth from older sedimentary rocks. With this proposed geological and geochemical model, the prospectivity for oil and gas deposits is greatly enhanced in aerial extent and possibly to a depth of 9 km.
AAPG Search and Discovery Article #91007© 1991 AAPG International Conference, London, England, September 29-October 2, 1991 (2009)