南大西洋两岸含盐盆地属于裂谷—被动大陆边缘叠合盆地.盆地具有相同的构造演化历史和相似的地层发育特征,但油气分布极不均衡.在对盆地类型进一步细分的基础上,讨论含盐盆地油气分布规律.根据盆地裂谷层系结构特征,将南大西洋两岸含盐盆地划分为2种盆地类型:凹凸相间型裂谷层系盆地和单斜型裂谷层系盆地;再根据裂谷阶段断阶发育特征和被动大陆边缘阶段沉积特征,每种类型又可进一步划分为2个亚类.在区域成藏条件分析的基础上,划分出盐下裂谷层系、盐上白垩系和第三系3套成藏组合,明确了各类成藏组合的成藏模式和成藏主控因素.从盆地类型角度出发,在分析不同类型盆地油气成藏条件差异的基础上,指出了不同类型盆地油气分布规律的差异及勘探潜力.%The salt basins in the South Atlantic are rift-passive continental margin superimposed basins.These basins have the same tectonic evolution history and similar characteristics of stratigraphic development, but the hydrocarbon distribution is extremely uneven.Based on the further subdivision of basin type,this paper discussed the distribution of hydrocarbon in the salt basins. First,according to the characteristics of stratigraphic structure which was deposited during the rift stage, the salt basins in the South Atlantic were divided into two kinds of basin:rift strata with characteristics of depressions and uplifts, and rift strata with monoclinic characteristics. According to the characteristics of stepped faults during the rift stage and the sedimentary characteristics during the stage of passive continental margin, each type can be subdivided into two subtypes. Second, based on the analysis of regional petroleum geological conditions, there are three hydrocarbon accumulation combinations in the study area, including pre-salt, post-salt Cretaceous and Tertiary hydrocarbon accumulation combinations, and this paper outlines accumulation models and the main controlling factors.Finally, from the point of view of the basin type,the difference of hydrocarbon accumulation conditions in different basins was pointed out,and the differences of hydrocarbon distribution in different basins were discussed. These results will guide further oil and gas exploration in the salt basins in the South Atlantic.
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