Institute of No.1 Company of Geophysical Exploration, Daqing Drilling Engineering Company, Daqing 163357, Heilongjiang, China

Wuxi fault is the boundary fault of western Wuerxun depression in Hailar Basin, which plays an important role in tectonic evolution to the depression. The development of Wuxi fault presents Episodic evolution feature and undergoes four formation stages, including of the separate chain, motionlessness, activation and reverse. Separate chain and activation stages are the main growth periods of the depression. The separate chain stage is characterized by tensional block structural style while in the activation stages developde in cap decollement struc tural style. Episodic evolution of Wuxi fault plays the control role in source rock evolution, reservoir and cap distribution and petroleum system of Wuerxun depression.