Forming Mechanism and Petroleum Geological Features of the Western-Central African Rift Basins (WCARBs)

Pan, Xiao-Hua (Research Inst. of Petroleum Exploration and Development, PetroChina) | Yuan, Sheng-Qiang (Research Inst. of Petroleum Exploration and Development, PetroChina) | Ji, Zhi-Feng (Research Inst. of Petroleum Exploration and Development, PetroChina) | Hu, Guang-Cheng (Research Inst. of Petroleum Exploration and Development, PetroChina) | Liu, Li (China Petroleum Engineering & Construction Corp, PetroChina)

OnePetro 

With the exploration activities of China National Petroleum Corporation (CNPC) in Sudan, Chad and Niger, more and more 2D, 3D seismic data had been required, a series of exploration and appraisal wells had been drilled, and more of other geologic materials had been obtained, such as well logs, core, geothermal gradient data, geochemistry data etc. Based on these abundant data and integrated application of geophysics method, physical modeling, computer modeling and geological analysis etc., the authors carried out an in-depth study on the Western-Central African Rift Basins (WCARBs), coming up with an understanding that the Basins are of passive rifts different from the so-called active ones formed in result of mantle up-welling. The WCARBs present unique petroleum characteristics including low geothermal gradient, aggregate thin-bedded hydrocarbon source rocks in syn-rift sequence, small-scaled post-rift sequence and high-angle basin-controlling major faults etc., and as a result, exhibit petroleum systems with unique characteristics, such as late and long-lasting oil generating window, high oil-expulsion efficiency, and fault-block dominated traps with rare rollovers etc. The deep study and analysis of the basin structure, sedimentary features and petroleum system obviously enhance the exploration discovery of WCARBs, which is the key factor of the successful E&P activities of CNPC in WCARBs.