Basin types and hydrocarbon distribution in salt basins in the South Atlantic
LIU Jingjing;WU Changwu;DING Feng;SINOPEC Petroleum Exploration & Production Research Institute;
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.