Journal of Petroleum Geology, Vol.4, No.1, pp. 35-56, 1981

©Copyright 2000 Scientific Press, Ltd.

PETROLOGY, PROVENANCE, AND DEPOSITIONAL ENVIRONMENTS OF THE RESERVOIR SANDSTONES OF OSSU-IZOMBE OILFIELD, IMO STATE, NIGERIA

Oluwatele Alabi Adedokun*

*Team Geologist/Interpreter, Shell Petroleum Development Co. of Nigeria, 21-22 Marina, PMB 2418, Lagos, Nigeria.

Abstract

Upper Eocene immature subarkoses derived from Cretaceous sedimentary rocks, older granites and metamorphic rocks, form the reservoir sandstones of the Ossu-Izombe oilfield, Imo State, Nigeria. These sandstones accumulated as part of a deltaic deposit. The vertical section of deltaic facies consists, from base to top, of a progradational sequence (prodelta and delta front), an aggradational unit (delta plain, marsh and interdistributary bay), and an overlying transgressive shallow marine interval. This sequence was penetrated by nearly all of the 15 wells drilled in the area. Reservoir sandstones are present within the distributary mouth bars, point bars, braided stream deposits, and the shallow marine interval.