Journal of Petroleum Geology, Vol.4, No.1, pp. 57-75, 1981

©Copyright 2000 Scientific Press, Ltd.

AN OIL MIGRATION AND RE-ENTRAPMENT MODEL FOR THE MARDIN GROUP RESERVOIRS OF SOUTHEAST ANATOLIA

L. Tufan Erdogan and Azat Akgül*

*Turkish Petroleum Corporation, Exploration Department, TPAO Arama Grubu, Müdafaa Cad. 22, Bakanliklar-Ankara/ Turkey.

Abstract

Oil migrates from a source into a reservoir rock and then, inside the reservoir rock, into a trap, and from the trap into a series of traps and reservoir rocks. The movement of oil is continuous and the interchange of oil between several reservoir rocks is totally independent of the source rock after a certain stage of migration. Each migration stage may cause quality changes in the properties of oil. A model is devised to account for oil migration and re-entrapment, and to explain the distribution of different quality oils in time and space. Variations in the API-gravity of oil, formation-water salinity, reservoir temperature and pressure, sulphur-content of oil, initial water content and recoverable oil reserves of oilfields can be important clues for the determination of migration directions and new prospects. These concepts were applied in a petroleum migration study of the Mardin Group (Aptian-Turonian) which is the most important reservoir rock of SE Anatolia.