A study on the controlling factors of petroleum accumulation in Shahejie Formation in Tong-Wang fault belt

Tong-Wang fault belt is located in the east of the south slope of Dongying Sag, Jiyang Depression.Shahejie Format ion is the major oil-bearing layer in this area.Through the research on hydrocarbon source rocks, reservoir rocks, pore fluid dynamic field, high quality transportation system and the fracture characteristics, etc., it is determined that the hydrocarbon source rocks in Niuzhuang Sag are mainly subdeep lacustrine-deep lacustrine dark mudstone and oil shale of Es4s and Es3.The dist ribution of oil and gas is circular or semi-circular with oil-generation subsag as the center;major types of reservoir in this area are the large delta reservoir sandbodies of Es3 and the lit toral-shallow lacustrine nearshore sand bar, offshore sand bar and sheet sandstone of Es4s and Es4z.Sand-fault transportation system is high quality transportation system in this area.Oil and gas moves along fault and sand body from north to Tong-Wang fault belt in the south where normal pressure with normal temperature and normal pressure with high-temperature exists.Oil-gas reservoirs in Tong-Wang fault belt are structural reservoirs which cont rolled by faults.The middle-shallow format ions of western Wang jiagang oil field are favorable areas for fault reservoirs and northern Wangjiagang region and the northwestward Chenguanzhuang region are favorable exploration areas for subtle reservoirs and fault-lithologic combinat ion reservoirs.