Abstract:

Based on geophysics, geochemistry, logging and well data, the present paper has unraveled the tectonicscontrolled distribution of the marine petroleum accumulations across the Sichuan Basin. Sichuan Basin is a superimposed basin in western China, of which the marine petroleum accumulations are chiefly under control of composite factors including the intracratonic sags, paleouplifts and basinmountain systems. Both the MianyangChangning and KaijiangLiangping intracratonic sags which were formed during the Xinkai and Emeishan taphrogenesis respectively have a firstclass control on the petroleum geological conditions, in particular the source rock quality and reservoir properties, which made the marine petroleum accumulate preferably in the periphery of the intracratonic sags. The paleouplifts formed during the Caledonian and Indosinian movements are favorable areas of petroleum migration and accumulation. Furthermore, the basinmountain systems have a significant effect on petroleum preserving conditions that controlled the final distribution of the marine petroleum, in particular during the LateMesozoic and Cenozoic times. Therefore, the favorable areas for marine petroleum exploration are those areas where the intracratonic sags, the paleouplifts and the basementcontrolled upliftbasin area or marginplate basinmountain systems superimposed across the Sichuan Basin.

Key words: intracratonic sag, paleouplift, basinmountain system, marine petroleum, Sichuan Basin