Structural influence on hydrocarbon entrapment in the northwestern Red Sea, Egypt

The northwestern part of the Egyptian Red Sea has attracted the attention: of many geologists because it lies at the triple junction of the main rifts between the Red Sea, the Gulf of Aqaba, and Gulf of Suez. The geometry of the fault system in this area of the basin clearly indicates an extensional setting. The area has a southwestward regional dip, and it has experienced more extension than the rest of the Gulf of Suez. Six tectonic stages, different in their stress history, sedimentary fill, and depositional setting, are recognized for the northwestern Red Sea: (1) Cambrian to early Cretaceous stage; (2) late Cretaceous to Oligocene stage; (3) early Miocene stage; (4) early to middle Miocene stage; (5) middle to late Miocene stage; and (6) post-Miocene stage. Magnetic, gravity, seismic, surface, and subsurface data from the northwestern Red Sea delineate several elongate structural highs separated by elongate troughs, Both highs and troughs have the same northwest-southeast direction as the clysmic trend. Some of the highs are dissected by cross elements that trend northeast-southwest and east-northeast-west-southwest and laterally offset these highs. The tectonic framework of the northwestern sector of the Red Sea had a significant influence on hydrocarbon generation, migration, and accumulation. The evidence for this influence includes the following: (1) the troughs form the main source kitchens where the Precambrian basement rocks are present at depths exceeding 4877 m (e.g;, Gemsa Trough); (2) the magnitude of throw on the clysmic fault is critical in the entrapment mechanisms; (3) the cross elements play a major role in the hydrocarbon migration and accumulation because they truncate the extension of most of the oil fields and form their bounding faults; and (4) all the discovered oil fields in the study area are structural and/or combination traps and show good matches to the magnetic anomalies.