An analysis of the inner-sag uplift control over hydrocarbon accumulation in Qingdong sag

As a half graben formed during Tancheng-Lujiang Fault activity since Mesozoic,Qingdong sag in the southern Bohai sea has experienced three stages of structural evolution,i.e.rifting,fault sagging and sagging.The evolution of its inner-sag uplift has resulted in the formation of various types of trap,with the reservoir quality improved simultaneously.Furthermore,the faults resulted from the tectonism have also made the inner-sag uplift become a favorable area towards which hydrocarbon migrated,and thick source rocks deposited in the two lows along both sides of the uplift has provided important oil and gas for hydrocarbon accumulation.Therefore,the inner-sag uplift has a greater exploration potential.