College of Earth Sciences，Jilin University，Changchun 130061，China

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 accumula- tion，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 hydro- carbon． The multi- periods of structural compression not only uplifted the studied area drastically，but also crea- ted a series of fault zones and large- scale slope belt． The structural compression also provided channel and suffi- cient power for migration of hydrocarbon to shallow layers． Based on these conditions，the favorable accumula- tion zone of heavy oil was predicted，which provided direction for heavy oil exploration in Nepa- Botuoba Sub- basin．