Characteristics of Strike-Slip Fault System and Its Control on Oil and Gas Accumulation in the FSD Region

Based on structural interpretation, this study investigates the strike slip fault system developed in the FSD area of the Songliao Basin. It is believed that the research area mainly develops various structural styles such as flower shaped structures, echelon structures, pull-apart grabens, braided structures, and shear fault zones. Divide the faults in the area into four stages, with the first stage being a northeast trending major fault that controls the sedimentation of the fault depression layer; The second phase is a nearly north-south trending fault; The third and fourth phases are two sets of strike slip thrust faults in a northwest direction, with nearly parallel strikes, indicating a transition of the fault from northeast to nearly north-south to northwest. The formation and evolution of strike slip faults are polyphase, and the fault development is inheritance and sectional. Restore the depth structure of the basement DLK top surface, revealing that the basin is low in the west and high in the east, and has a inheritance nose structure in the southeast; From the current structure, the basin is low in the northwest and high in the southeast, with locally developed small-scale forward structures, making it a favorable location for oil and gas accumulation. The southeast of the basin is a inheritance nose structure, and the basement DLK anticline gradually increases in amplitude, which is the main migration direction of oil and gas accumulation. It can be considered that strike slip faults destroyed early ancient oil reservoirs and were the main pathway for late oil and gas migration and accumulation, while strike slip fault zones caused segmented distribution of oil and gas.