On the basis of the analysis of natural gas geological factors of Upper Tertiary Xujiahe Formation in the middle part of West Sichuan Depression, the gas resources are calculated by reservoir volumetric method. The research results show that the reservoir formation conditions are superior and there are rich gas resources. The Xujiahe Formation has good hydrocarbon\|generating conditions, its source rock is characterized by big thickness, wide distribution, high organic matter abundance, good quality and large gas generating amount. The reservoir rock has low porosity and low permeability and obvious heterogeneity. The sandstone reservoirs mainly lie in the second and the fourth members of Xujiahe Formation, their direct regional caprocks are the third and fifth members of mud shale, respectively and they have wide distribution, big thickness and stable lithology. Trap is abundant and its type is varied in the Xujiahe Formation. There is a good association of source, reservoir and cap rocks. The natural gas resource of Xujiahe Formation in the middle part of west Sichuan depression is 5431.2 hundred million cubic meters. There is material base for forming large to middle gas fields and there are great exploring prospects. The east and west sections of the almost latitudinal direction uplift from Mianzhu to Yanting, the regional slope of the Longmen mountain front and the gentle slope of the east part of the depression are the favourable zones for oil and gas migrating and accumulating.
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