M. G. SALAH Abou Sayed¹, Mohamed Mersal²

(1) RC-Squared, Abu Dhabi, P.O. Box 46800, United Arab Emirates
(2) UAE University

ABSTRACT: Petrography and Hydrocarbon Potential of Lower Cretaceous Carbonates In The United Arab Emirates

The Lower Cretaceous carbonates assigned to the Kharaib Formation in the United Arab Emirates (UAE), are up to 120 meters thick, and represent cyclic sedimentation. The formation consist of interbeded dense limestones that were deposited in an intertidal lagoonal setting, and porous carbonates, that were deposited in a shallow shelf setting on a carbonate ramp. The Kharaib Formation includes four microfacies associations. Petrographic analysis suggests a diagenetic history divisible into marine phreatic, mixed phreatic, meteoric phreatic, and shallow burial stages. The Kharaib carbonates produce oil at several super-giant oilfields and have good reservoir quality, with net pay up to 70m and average porosity of 21%, and permeabilities range from 0.1 to 120 millidarcies. Reservoir quality depends on the effect of diagenetic processes such as leaching, recrystallization, fracturing, stylolitization and secondary pore filling. Pore types are dominantly vuggy, mouldic, associated with interparticle porosity, and formed by dolomitization. The dense carbonates of the Middle Kharaib and Hawar Members form potential vertical seals for the underlying Lower and Upper Kharaib Members, respectively. They also provide lateral seals when brought into faulted contact with porous reservoir carbonates.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado