Main controlling factors about hydrocarbon accumulation in fault-block reservoir in Shahejie Formation of Dongying Sag

Fault-flock reservoirs are extensively distributed in Dongying Depression,and Shahejie Formation is the highlight of exploration and exploitation.According to the statistical analysis of the geological features of fault-block reservoir in Shahejie Formation of Dongying Depression,main controlling factors of fault-block reservoirs are studied for oil-gas exploration.The fault-block reservoirs of Shahejie Formation in Dongying Depression are mainly distributed in the central anticlinal belt,the northern steep slope belt and the southern gentle slope belt.The reservoirs are distributed in the first member,second member and the upper part of third member of Shahejie Formation.According to this study,the distribution and accumulation of fault-flock reservoirs is mainly controlled by the source rocks,faults,abnormal pressure and physical property of reservoir in Shahejie Formation of Dongying Depression.The excellent source rocks from upper Es4 and lower Es3 reservoirs provide the base of hydrocarbon accumulation and the abnormal pressure provides the driving force for hydrocarbon migration.The faults not only control the hydrocarbon migration,but also control the formation of trap.The reservoir distribution is controlled by the physical property of reservoir.The reservoirs,with porosity being higher than 15% and permeability being higher than 10×10-3 μm2,are favorable for hydrocarbon accumulation.