Accumulation conditions of outside source heavy oil in NepaBotuoba Sub-basin,Russia and prediction of distribution

In terms of tectonic evolution and petroleum geological conditions of the Nepa-Botuoba Sub-basin and its adjacent sub-basins,the accumulation conditions of the heavy oil were analyzed. The studied area had plenty of oil and gas accumulation,but there were no developed source rocks. It is a typical outside source accumulation,whose origins from thick high-quality source rock deposited in the adjacent sub-basins. The shallow layer has favorable heavy oil reservoir conditions and poor sealing conditions,which benefits the thickening of hydrocarbon. The multi-periods of structural compression not only uplifted the studied area drastically,but also created a series of fault zones and large-scale slope belt. The structural compression also provided channel and sufficient power for migration of hydrocarbon to shallow layers. Based on these conditions,the favorable accumulation zone of heavy oil was predicted,which provided direction for heavy oil exploration in Nepa-Botuoba Subbasin.