Abstract: The Bahar Oil and Gas Field, South Caspian Sea - Geology and Development

NARIMANOV, A., T. ABDULLAEV, and E. VALIEVA, L.G.M. FALT, T.S. OLSEN and O. SKONTORP

Bahar is a large gas and oil field in the South Caspian Sea, c. 40 km off the Azerbaijan coast at Baku The accumulation is structurally controlled, contained in a gentle anticline above a deep-seated thrust in the South Apsheron Trough. Hydrocarbons are accumulated in a thick succession of Middle Pliocene paralic clastic deposits, the Productive Series, now buried to depths of 4000 to 5000 m. The ancient Volga and Kura River deltas accumulated thick fluvio-deltaic successions in the rapidly subsiding South Caspian Basin, Porosity is reduced to c. 15-18%, mainly through compaction. Little diagenetic porosity loss is observed.

Hydrocarbons originate from source rocks matured in the (early) middle oil window. There are indications that the source is of algal/lacustrine origin.

Initial hydrocarbon distribution and production experience show that the reservoirs are compartmentalized, due to a combination of internal stratigraphic and fault seals. Initially tilted contacts indicate a dynamic pore fluid system. Pore fluids have escaped from large depths through a mud volcano in the southern part of the field. Eruptions have occurred in recent historic time.

Bahar was discovered 1968, and production started 1970. C. 220 wells are drilled, and production, through depletion, has been primarily aimed at gas recovery but significant oil production has also taken place from the Svite Pereriv and Balakhany X intervals. A potential for increased oil recovery exists and additional reserves may be present in extensions of the field.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria