Petroleum Potential of the Gemsa Basin, Southern Gulf of Suez, Egypt

By

 Mahmoud Abdelrahman Atta¹, Ahmed Nabil Shahin², David Blanchard¹, Henry David³

(1) Ocean Energy Egypt Ltd, Cairo, Egypt (2) El Alamein Petroleum Company, Cairo, Egypt (3) Ocean International Ltd, Houston, TX

 The onshore Gemsa Basin is a large northeast-southwest trending half graben in the S. Gulf of Suez. It remains under explored, but could have the same hydrocarbon generative potential of the prolific offshore half-grabens in this part of the Gulf.

The thick sedimentary section consists of Pre-Rift and Syn-Rift rocks of Cretaceous to Recent age, separated by significant unconformities and deposited under varying depositional environments. Five organically rich, fine grained units within both pre- and syn-rift sequences are recognized as potential source rocks, with the main ones being mature for hydrocarbon generation. Expulsion from the Cretaceous source rocks (Sudr & Brown Ls) began 5 to 7 million years ago, and from the Miocene (Kareem & Rudeis fms) between 3 to 5 million years ago.

Thermal and burial history modeling, calibrated to a data base of measured kerogen and maturation parameters, was done on several basinal wells in the area, as well as on hypothetical ‘pseudo wells’. The results indicated the amount of hydrocarbon generated exceeds the proven hydrocarbon volume found to date in the vicinity of the areas of maturation. Therefore, significant potential remains for commercial hydrocarbon discoveries in the Gemsa Basin.

Due to a very thick overburden of evaportic rocks, the present day seismic data are not of adequate quality or resolution to accurately image potential stratigraphic and/or structural traps. Recent advances in seismic acquisition and processing technology is expected to improve the image of the subsurface. Multidisciplinary integration of this new data with other exploration tools should yield a new prospect inventory for this basin.