Organic geochemical studies of some Early Cretaceous sediments, Abu Gharadig Basin, Western Desert, Egypt

A total of 81 shale samples from the Early Cretaceous sediments of seven wells in the Abu Gharadig Basin, were analysed for organic matter quantity, type and maturation. The total organic carbon content of analysed samples ranges between 0.5 and 2.67 wt%, indicating a fair to good organic content. The location of investigated samples on the van Krevelen diagram reflects the presence of kerogens type IV (without hydrocarbon potential), type III (gas-prone) and type II-III (oil and gas-prone). The estimated temperature of maximum pyrolytic hydrocarbon generation of analysed shales ranges between 426 and 447 degrees C, indicating immature to thermally mature organic matter. The shale beds of Kharita Member from the northcentral part of the study area, at depths more than 2164 m, represent gas-prone source beds, while those of Alam El-Bueib Member, at depths more than 2545 m, can be considered potentially as active oil and gas-prone source beds. The present study reveals that the Early Cretaceous Alam El-Bueib Member is more enriched in thermally mature type ill and It-ill organic-rich shale beds, and consequently can be regarded as the potential source for the oil and gas accumulations in the carbonate reservoirs of;the Alamein Member and sandstone reservoirs of the Kharita Member in the Abu El-Gharadig Basin. (C) 1998 Elsevier Science Limited.