Control of Fault Intensive Zones on Hydrocarbon Accumulation: a Case Study of Qijia-Gulong Area in Northern Songliao Basin

Abstract

The top surface faults of Quantou Formation in Qijia-Gulong area in northern Songliao basin are widely developed and densely zoned, controlling the deposition and accumulation of Fuyu oil layer. To clarify the control role of fault intensive zones, a combination of plane and section is used to analyze the plane and section characteristics of fault intensive zones, analyze their impact on reservoirs and source rocks, and clarify the reservoir control mode. The results show that: (1) The faults of Fuyu oil layer in Qijia-Gulong area are unevenly distributed and densely zoned, the Western intensive zones are NNE direction, and the eastern intensive zones are NW direction; (2) The western part of the fourth section of Quantou Formation in the study area is in the direction of provenance. The same direction fault promotes the sand body to transport into the basin, and the reverse fault blocks the sand body migration. When the fault trend is the same as the direction of provenance, the sand body is dispersed along the fault strike; (3) Oil and gas migrate to the high part of the structure through the fault sand body transport path. In the west of the study area, oil and gas are accumulated in the footwall of the antithetic fault at the boundary of the fault intensive zone, which in the East are mainly enriched in the "concave uplift" structure formed by inversion.