Characteristics of Faults in Majiatan Area of West Ordos Basin and Their Petroleum Reservoir Controlling Model

The tectonic framework in Majiatan is controlled by basement faults and has the features of belting in east-west direction and blocking in north-south direction. There are three fault systems, namely, flower-fault system in the north, inversion-thrust fault system in the central part, and imbricate structure-obduction zone fault system in the west, forming two classes of pressure-strike slip and inversion-thrust faults and eleven kinds of fault combinations. The study area has eight kinds of fault growing models, and the distribution of petroleum reservoirs is controlled by faults. This paper sums up three kinds of models for fault controlling petroleum accumulation: ①fault-reservoir strata transporting-flower structure traps accumulating hydrocarbon in the source rock; ② fault-reservoir strata transporting-fault inversion structure traps accumulating hydrocarbon outside the source rock; ③ fault-reservoir strata transporting-thrust fault structure traps accumulating hydrocarbon outside the source rock.