Since the 1980s,the porous dolomite reservoir of Huanglong Formation of Carboniferous in Sichuan Basin has been an important exploration object and a key production layer in the east Sichuan Basin.With the gradual increase of reserves utilization,it is urgent need for discovery and replacement of new reserves.In recent years,with the addition of high-quality seismic data,combined with drilling and outcrop data,comprehensive geological analysis of Carboniferous strata,Silurian hydrocarbon sources and reservoir-forming conditions on the western side of Huaying Mountain has been made,and three main understandings have been obtained:(1)Carboniferous strata are distributed in a large area on the western side of Huaying Mountain.The favorable area of carbonate rocks is over 8 000 km2,and the predicted thickness is up to 40 m,which provides stratigraphic and sedimentary basis for the formation of large-scale reservoirs.(2)Pingchang-Bazhong and Guang'an-Quxian large trap groups with a total area of 5 460 km2 are developed under the control of paleo-uplift slope belt,stratigraphic denudation belt and fault belt,which have favorable conditions for large-scale reservoir formation,(3)The Pingchang-Bazhong trap development area,if the Carboniferous reservoir is developed,has good gas source conditions,well-developed structural traps,and favorable accumulation combination of lower sources and upper reservoirs,so it is a favorable area to explore for large-scale natural gas reserves.