STRUCTURAL FEATURE AND PETROLEUM ACCUMULATION IN XIAERMEN OILFIELD, THE BIYANG DEPRESSION

Based on 3D seismic data and well information and combining with regional tectonic background, the structural feature and its evolution were analyzed and formation history of hydrocarbon accumulation was restored in Xiaermen oilfield. Xiaermen structure is an anticline complicated by the later faults. The tectonic activity at the end of Paleogene was characterized by compression and uplift, and folds were developed in Biyang depression. The faults in the depression were formed in the end of Neogene. The structural evolution and formation of hydrocarbon accumulations passed through 3 stages, i.e.(1) subsidence and deposition with development of reverse drag anticline in Early Paleogene, early migration and accumulation of hydrocarbon; (2) regional compression and uplift in the end of Paleogene, formation of anticline lithology reservoirs; and (3) extension and fault movement in the end of Neogene, complicated anticline, destruction of reservoir, and formation of secondary fault lithology reservoirs.