塞内加尔盆地北部次盆白垩系被动大陆边缘深海扇演化特征及主控因素

被动大陆边缘深海扇是当今海洋深水油气勘探的热点.识别深海扇,明确其时空演变特征,总结关键地质因素对其发育的控制作用,对于建立深海扇成因与预测地质模型具有重要意义.本文通过地震与钻井资料综合解释,分析塞内加尔盆地北部次盆白垩纪被动大陆边缘时期的构造-沉积演化特征,识别深海扇体,并分析其岩性、形态与规模的演变特征;然后分析...

Evolutionary characteristics and controlling factors of deep-sea fans in Cretaceous passive continental margin basin,Northern Subbasin,Senegal Basin

Deep-sea fan reservoirs in passive continental margin basins are among exploration hotspots in offshore petroleum exploration. Understanding the spatiotemporal evolution of deep-sea fans can help refining geological models by enhancing the exploration and development of related reservoirs. Based on seismic and drilling data, different types of deep-sea fans with characteristic lithologies, shapes, and sizes are identified along the passive continental margin of the Senegal Basin. Factors such as sea-level changes, sediment supply, and paleo-geomorphology were integrated into the interpretation. This study shows that the passive continental margin dates back to the Middle Jurassic. During the Cretaceous Age, the study area underwent three stages of tectonic-sedimentary evolution: (1) carbonate platform build-up stage during the Neocomian and Aptian Ages; (2) sedimentary stage of clastic deposition on a continental fault-slope from the Albian to Santonian Ages; and (3) sedimentary stage of clastic deposition on a gentle continental slope (slope-break) during the Campanian and Maastrichtian Ages. During these periods, five types of deep-sea fans with varied lithologies, morphologies, and sizes developed in the study area. Several factors could have influenced the development and evolution of deep-sea fans. Among them, global sea-level changes and terrestrial clastic supply had the greatest influence on the texture and size of the fan, while continental slope geomorphology determined the shape and distribution of the fan reserviors.