关键词: 四川盆地, 三叠系, 飞仙关组, 天然气勘探, 鲕粒滩, 气藏

Abstract: Some giant gas fields such as Puguang. Luojiaihai,Dukouhe and Tieshan gas fields have been discovered in Feixianguan Formation of the Lower Triassic in Sichuan Basin in recent decade years. Natural gas mainly accumulated in polite beach sedimentary facies of carbonate platform edge around Uuanglian g trough in Sichuan Basin. The topography of polite beach was high. The polite beach was often uncovered and subjected to freshwater leaching due to sea basin vibration. The sheets of polite were changed into the dolomite with dissolved pore of oolite,calcite dolomite with dissolved pore of polite and dolomitic limestone with dissolved pore of polite. These rocks in Sichuan Basin are the best reservoirs with the mean porosity of 8.16% and the mean permeability of 93. 326×10^-3μ m².The major gas reservoirs in Sichuan Basin were litho-structural combined reservoirs. There found 104 seismic anomalies of polite beach in the eastern Sichuan Basin using the recognition mode of seismic anomaly of polite beach. The new targets for future gas exploration in Sichuan Basin were provided.

Key words: Sichuan Basin, Triassic, Feixianguan Formation, natural gas exploration, oolite beach, gas reservoir