Based on comprehensive knowledge of deep reservoirs all over the world and petroleum geological features of superimposed basins in western China，this paper recognizes three key challenges of petroleum exploration in the deep of superimposed basins in western China.The first challenge is thathydrocarbons generated inmulti-phasesm ix together and their origins are not clear，making ithard to select leads.The second challenge is that fractures and dissolved pores/cavities m ix together in reservoirs and their origins are unclear，making ithard to predict favorable plays.The third challenge is thatphases ofhydrocarbon vary greatly and the distribution of hydrocarbon is influenced by high pressure and temperature，low porosity and permeability and several driving forces ofm igration，making it difficult to predict exploration targets using existing pool-form ing theories.Therefore，to accelerate hydrocarbon exploration in the deep of superimposed basins in western China，we have to find answers to three key issues:（i）multistage tectonic overprinting and deep hydrocarbon generation and evolution;（ii）developmentmechanism and pattern of deep effective reservoirs;（iii）composite pool-form ingmechanism and accumulation pattern ofhydrocarbons in deep strata.It is suggested to adopt a research method that integrates forward modeling with inversion analysis of hydrocarbon accumulation process and a technical route of“geological condition-mechanism pattern of hydrocarbon accumulation”.Tarim Basin and Junggar Basin can be choosen as the focus of study as they have the greatest deep petroleum resource potential.It is expected to develop theories on composite hydrocarbon accumulation in the deep of superimposed basins in western China and supporting techniques to predicthydrocarbon distribution.These new theorieswill promote hydrocarbon exploration and fast reserve growth in the deep ofwestern China basins. Keywords:hydrocarbon distribution pattern，hydrocarbon accumulation，deep hydrocarbon exploration，superimposed basin in China
