| The passive continental margin of West Africa is becoming one of the most attractive areas for petroleum exploration. Based on the comparison and analysis of Gabon Basin, Lower Congo Basin and Kwanza Basin, the systematic petroleum characteristics were summarized. The history of these basins along the passive margin is controlled by the general framework of the opening of the South Atlantic Ocean,with the breaking up of the proto –continent Pangea. These basins have experienced four tectonic stages of pre-rift (before J3), syn-rift(J3—K1), trastional(K1) and post-rift（K2—Q）. Aptian salt, which relates to Tristan hot spot activity and arid climate at that time,controls vertical distribution of hydrocarbon,and separate the upper salt petroleum system from the lower one in these basins. Came room-Angola salt basin group,in which Late Jurrasic-Early Cretaceous deposition has deep lacustrine hydrocarbonrich sources,and Cenomanion-Satonian and Cenozoic marine shale is also the main sources; transitional stage deposited very thick evaporate rocks which are the most important cap in these basins. The reservoirs are the Cenozoic turbidite rock and the common traps are salt-related structures and stratigraphic lithologic traps while syngenetic faults and salt windows serve as excellent channels for migration of hydrocarbon. All these conditions match with each other and favorable to form the large-scaled oil fields. |
