Comparative Study On Tectonic Evolution Of Rift Basins In East Africa And North Sea And Their Control On Hydrocarbon Accumulation

The continental rift basin is a favorable region for oil and gas accumulation.As an important basin type,it plays an important role in oil and gas exploration.The East African rift basin and the North Sea rift basin are typical oil-gas rift basins on the African plate and the European plate respectively.The special tectonic setting and formation mechanism create their complex basin characteristics and oil-gas accumulation laws.Therefore,it is of great significance to clarify the structural characteristics and oil-gas control between them for the exploration and development of rift basins.Limited by relevant data,exploration degree,and geological understanding,there are still differences in the understanding of the structure,formation,and evolution of the two rift basins;Predecessors mostly studied and analyzed a single rift basin,and lacked the organic combination and comparative analysis of rift basins in multiple different regions,to obtain the theoretical and practical laws;Meanwhile,from the perspective of global rift basin analysis,it is clear how the extensional structure controls the oil and gas accumulation in the rift basin.In this paper,based on the predecessors’ research on the east and the north sea of these two blocks of related literature,monographs and reports,such as basic data application of regional structure and petroleum geological research method,the systematic study of regional tectonic characteristics,the East African rift basin and the north sea basin tectonic style,formation mechanism,evolution and hydrocarbon accumulation regularity based on comparison research,finally clarify their internal relation.The following insights were obtained:(1)The East African rift basin and the North Sea rift basin are active trigeminal rift systems or branches formed under the action of mantle plumes under different temporal and spatial backgrounds.The East African rift basin mainly develops single fault half-graben and single fault migration structural styles.(2)The North Sea mainly develops double fault graben type and salt-related structural styles.The evolution of rift basins in East Africa can be divided into two main stages:pre-rift and syn-rift,while the North Sea can be divided into three main stages:pre-rift,syn-rift,and post-rift.In terms of evolution degree,East Africa is lower than the North Sea,which is still in the stage of fault depression,while the North Sea is in the stage of thermal cooling subsidence.(3)For rift basins,the basins formed by the same genetic mechanism and evolution mode with different pre-existing tectonic backgrounds and different evolution times are quite different,that is,the factors controlling the evolution of rift basins are diverse.(4)East African rift basin and North Sea rift basin have different structural characteristics and evolution degrees,which play an important role in controlling the development of sedimentary strata and oil and gas accumulation,and a variety of structural styles are associated with rich trap types.