Hydrocarbon pooling conditions and exploration potential in the Fulin sub-sag of the Zhanhua Sag,the Jiyang Depression

Fulin sub-sag is a secondary structural unit in Zhanhua sag of Jiyang depression,Bohai Bay Basin. Geochemical analysis and oil-source correlation show that the sag not only contains mid-and low-mature oils from the central and eastern parts of the sub-sag,but also mature oil from the third member of the Paleogene Shahejie Formation in Gunan sag,in which the mid-mature oil is predominant.The conditions and characteristics of hydrocarbon migration determine the formation and distribution of oil and gas reservoirs.The complex pathway network consisting of unconformities and faults in Fulin sub-sag and its periphery as well as the spatial configu- ration of reservoir sandbodies in various strata controlled the migration and distribution of oil and gas.