Mesozoic tectonics-sedimentary characteristics and accumulation conditions in the Southwest African Coastal Basin

The Southwest Africa Coastal Basin is located in the African coast of the South Atlantic, which is formed by the superimposition of the Upper Jurassic-Lower Cretaceous rift basin and the upper passive continental margin basin, and is a hot exploration area of oil and gas. In this paper, based on the investigation of foreign petroleum geology, seismic and logging data, the tectonic morphology and sedimentary filling characteristics of the Southwest Africa Coastal Basin during the Mesozoic are described in detail, and the longitudinal evolution and transverse migration are clarified. Combined with the drilling and testing data of known oil and gas fields, the basic geological conditions of oil and gas enrichment in the basin are comprehensively analyzed. The study shows that the Southwest Africa Coastal Basin was formed in the late Jurassic period. In the early stage, the basin was characterized by intense faulting and volcanic activity, and the interior of the rift basin was filled with a large number of sandstones and shales. After the transitional stage of the Cretaceous Barremian Epoch and Aptian Epoch, it entered passive continental margin stage in Albian Epoch. In thermal subsidence and passive continental margin stage, the basin is mainly filled with fine marine facies with a small amount of carbonate and salt rocks. The main source rocks in the basin were formed in the Aptian Epoch, and the overlying clastic reservoirs in the Upper Cretaceous formed oil and gas accumulation assemblages.