Formation and evolution of petroliferous basins in African continent and their hydrocarbon distribution

摘要

There are eighty sedimentary basins in five different types in African continent,i.e.craton sag basin,foreland basin,intermountain basin,passive margin basin and rift basin,which underwent the stress environment of stable depression-compression-extension.The first three types of basins had been intensely influenced by Hercynian and Alpine tectonic movement,while the later two types of basins always exist in a stable extension environment.Different basin evolution caused the obviously hydrocarbon distribution difference.In North Africa,marginal craton sag and rift basins show great expedition potential of hydrocarbon,marginal craton sag basins had good formation and preservation of Lower Silurian hot shale,tectonic-strata traps and migration pathway formed by Hercynian unconformity,and rift basins had excellent Upper Cretaceous marine source rocks and good hydrocarbon preservation with little tectonic activity.Meanwhile,in the salt-containing passive margin basins and delta basins of West Africa,thick strata containing high quality source rocks and plastic strata were well developed.Source rocks of high maturity,good hydrocarbon preservation,growth faults and deformational structure traps were formed by abundant overlying sediments and sources supplied from Tertiary large water system.