Study Of Fault System And Reservoir-Controlling Mechanism: A Case Of Shulu Slope, Jizhong Depression

The study area is located in South Jizhong depression, Bohai Bay basin, Shulu Slope is a typical half-graben. Hydrocarbon source rock were deposited in Es⁴ and Ek. Three sets of regional caprocks were on top of hydrocarbon source rock, The distribution of these three sets of regional caprocks control hydrocarbon enrichment in Es^3-3、Es²、Es¹.Traps dominated by fault is a top priority in the study area. Through the study of geometry and kinematics of fault in the study area and according to the fault segmentation theory, trap of Shulu slope can be divided into 3 types: traps formed in hanging wall of normal fault which orientation is similar to orientation of the formation, traps formed in footwall of normal fault which orientation is contrary to orientation of the formation, traps formed in many intersecting faults. The length, size, orientation, strike of these fault would influence on acreage of their traps.Shulu Slope can be divided into three periods of tectonic movement: Es³-Es², Es¹-Ed, Ng. According to the geological evolution, we build 6 sets of fault systems in Shulu slope. Type I start from Es⁴ to Es³, Type II start from Es¹ to Ed, Type III start from Ng to surface, Type I- II start from Es⁴ to Ed, Type II- III start from Es¹ to surface, Type I- II- III start from Es⁴ to surface.Hydrocarbon generation of Shulu slope is start from middle of Ed period. So type I, type II, type I- II play an important role in gathering hydrocarbon. Type III, Type II- III had no effectiveness in Shulu slope. Type I- II- III play an important role in the migration of hydrocarbon, but not all of them could migration hydrocarbon. Only the fault which breakthrough cover layer could migration hydrocarbon upward. We use the relations between fault throw and thickness of its cover layer to build a formula to distinguish whether or not hydrocarbon could migration upward.