Study on the sedimentary system of Member 1-S of Shahejie Formation and Dongying Formation of the Qikou sag in Bohaiwan basin,China

According to the systemic analysis of drilling data,well log,non-seismic and seismic data,and combined with the previous research results,Member 1-S of the Shahejie Formation and Dongying Formation of Paleogene System is considered to be an integrity of second order sequence(LSC4).The result of the research on the sedimentary system indicates that several types of sedimentary facies have developed in LSC4,including alluvial fan,fan-delta,delta,underwater fan,lakes and so on.The delta front mouth bar and sheet sand microfacies and deep-water turbidite fan sand are the potential favorable areas for lithologic reservoir.Exploration practice indicates that Member 1-S of the Shahejie Formation and the Dongying Formation in the Qikou sag have a great exploration potential for oil and natural gas.