摘要
Exploration potential of natural gas in the Sinian,Sichuan Basin,was analyzed based on the research on evolution of Leshan-Longnüsi palaeouplift and reservoir forming conditions such as sedimentary facies,source rocks,reservoirs and caprocks.The Sinian has a potential to form large gas fields in the Sichuan Basin:(1) A large-scale inherited palaeouplift provides conditions for oil/gas formation and accumulation.(2) Stable sedimentary environment guarantees the extensive development of source rocks and reservoirs.(3) Sinian Deng-2,Deng-3 and Deng-4 reservoirs overlap each other and are developed widely.(4) Multiple source rocks overlay vertically and are distributed widely,superimposed between reservoirs like "sandwiches".(5) The Sinian has good preservation conditions,regional mudstone cap rocks are thick and faults are not developed.Considering favorable reservoir forming conditions,four favorable prospective areas are selected: Leshan-Longnüsi Palaeouplift,Southeast Sichuan,East Sichuan,and Northwest Sichuan.The Leshan-Longnüsi palaeouplift is the most favorable area,where inherited palaeostructural traps in the core are first priority and the litho-stratigraphic gas reservoirs in the slope deserve exploration.
