Study on petroleum accumulation of deep zone in Shiwu Fault Depression south of Songliao Basin

Shiwu Fault Depression is a composite basin where fault superimposed, its deep formations included Denglouku Formation (K1d), Yingcheng Formation (K1yc), Shahezi Formation (K1s) and Huoshiling Formation (J3h). Two sets of source rocks and good reservoir-cap rock combination deposited in deep zone of Shiwu Fault Depression. Plenty of faults and unconformities were formed by the tectonic movement in Shiwu Fault Depression, so that effective migration paths of petroleum accumulation were formed. Simultaneously, some effective faults, faulted nose structural traps and some unconformity traps were formed. Generally speaking, there is available source-reservoir-cap assembly in the deep part of Shiwu Fault Depression which formed three modes of petroleum accumulation including the younger soure and older reservoir mode, the self soure and reservoir combination and the older source and younger reservoir mode.