The Kareem/Rudeis Carbonate reservoir of Lower Miocene time represents the main reservoir in the
western flank in Zeit Bay Oil Field, containing approximately 50% of the total hydrocarbon reserves. The carbonate
platform developed upon the extensional tilted fault blocks located on the western rift margin.
This study aims to evaluate the reservoir characteristics of the Kareem/Rudeis carbonate reservoir based on core analysis, petrographic observations and petrophysical determinations.
Petrographic analysis and petrophysical investigations of these carbonates, using the available electric logs and core data, show that the carbonate facies can be distinguished into several litho-facies. The upper part is a limestone body which is developed as separate mound along the western flank. The dolomite facies which underlies the limestone and is considered as a secondary dolomite derived by the diagenetic dolomitization processes on the originally deposited limestone. This dolomite facies can be subdivided into two zones according to the log response and cuttings description. The upper one is characterized by the presence of an anhydrite content with low gamma ray. The lower dolomite is characterized by a relatively high gamma ray which is caused by incorporation of uranium into dolomite crystal lattice reflecting somewhat different chemistry of the dolomitized fluids than the overlying low-gamma dolomite, and presence of sand which was reworked from the underlying Nubia Sandstone Formation