Controls of intensively faulted zones on hydrocarbon migration and accumulation: An example of Fuyu oil layer in Xingbei area, Songliao Basin

The types and genetic mechanism of intensively faulted zones in the Fuyu oil layer in the Songliao Basin were studied based on 3D seismic data and combined with the plane and profile characteristics of intensively faulted zones, so as to identify the controls of intensively faulted zones on hydrocarbon migration and accumulation. Reservoir dissecting technology was applied, and the distribution characteristics of intensively faulted zones, hydrocarbon and sand bodies were taken into consideration. Several conclusions were made as follows. (1) Intensively faulted zones are widely distributed in the Fuyu oil layer in Xingbei area, including the parallel graben belts caused by stretching and the hybrid intensively faulted zones caused by coupling. (2) Sheltered by transverse intensively faulted zones, the ramp zones to the south and east of the central anticline have no oil or gas enrichment. Hydrocarbon was enriched in the hanging wall of boundary reverse faults outside intensively faulted zones. The larger the scale of fault displacement, the higher the degree of oil enrichment. (3) The boundary faults of consequent intensively faulted zones can be hydrocarbon migration pathways along the fault strike. Tectonic inversion occurred in the central anticline zone, and the "uplifted graben" morphology formed in intensively faulted zones, where oil and gas accumulated.