Puguang gas field has typical slope facies on platform margin.Large reef and shoal facies reservoirs have been deposited on the slope with relatively obvious chimney effect

i.e.chaotic and disrupted wave groups with push-down shape.The reservoir prediction method has been developed on the basis of analyzing the known gas fields.It is then used to make a comprehensive prediction of the reservoirs in northeastern Sichuan basin.It is found that the Malubei structure in Tongnanba structural zone and Jiulongshan structure in Cangxi County show the characteristics of typical sequence stratigraphy of platform margin facies.The predicted Cangxi reef and shoal facies show the characteristics of typical progradational sequence stratigraphy with reliable push-down. It is predicted that there would possibly be a super large reef and shaol facies gas field in Changxing-Feixianguan Formations in Cangxi area.The sequence stratigraphic characteristics of the Malubei reef and shoal facies are basically the same with that in Puguang gas field

i.e.a slope zone where large reef and shoal facies reservoirs would have been developed.It is

therefore

predicted that there would be a large gas reservoir.