Hydrocarbon accumulation in rifted basin tectonic units:A case study of Huoduomoer tectonic zone in the Hailaer Basin

The Hailaer Basin is a complicated rifted basin which has various hydrocarbon accumulation distribution patterns. We identified the faults and unconformities of the Huoduomoer tectonic zone, and predicted sandstone thickness by inversion based on seismic, logging and well core data. We found that faults, sandstones and unconformities are three dominant hydrocarbon accumulation factors in the research area by analyzing the relationship among them. They not only controlled hydrocarbon migration but also impacted the accumulation process. In the slope belt, sandstones and unconformities provided hydrocarbon migration routes, and reservoir lithology and structural-stratigraphic reservoirs were developed. In the uplift area, faults, unconformities and sandstones worked as hydrocarbon migration routes, and buried hill reservoirs and shallow structural-stratigraphic reservoirs were developed. In the shallow strike-slip fault belt, faults and sandstones allowed hydrocarbon migration, and structural-stratigraphic reservoirs were developed. There are mainly three categories of hydrocarbon accumulation:slope belt mode, strike-slip fault belt mode and buried hill mode. Hydrocarbon accumulation was controlled by faults and unconformities in the uplift area, and by sandstones and lithologic traps in the slope belt.