Sedimentary And Reservoir Characteristics Of The Fourth Member Of The Middle Triassic Leikoupo Formation In The South

Focus on Lei-4of the middle Triassic Leikoupo formation in southwest of Sichuan basin,guided by the theories of sedimentary petrology,reservoir geology,natural gas geology and other related theories.Through the study of a large number of literature, combination with drilling cores,micro-thin slices measured logging and a variety of analysis data,we have studied the strara, the types and characteristics of sedimentary facies,diagenesis and reservoir, analyzed the influencing factors of reservoir development, and pick favorable exploration zone.From those information,we believe that T2l4should be divided into T2l43, T2l42, T2l41. Generally,Leikoupo Formation is stable,but influence by mountain Longmen tectonic zone, Kangdian paleo continent and Luzhou-Kaijiang paleo uplift’s tectonic uplift,sedimentary and differential erosion, the center of the area which we studied(along Xinjin-Penxian-Zhongjiang-Chengdu-Meishan) has the biggest thickness, the residual formation thickness get thinner from northwest, southwest and southeast.In this area, T2l4from south,and T2l43from north were usually be eroded. From this study, Lei-4in this area belongs to the epicontinental platform environment and can be divided with platform, open platform, table point sand and a plurality of microfacies, which table point sand in T2l43is the favorable microfacies belt, dolomitic flat is the second.The best physical quality of rock type was crystal powder dolomite, grain dolomite was the second, the major storage is inter granular dissolved pore. The major influent space is the fracture. The range of profitability reservoir was around Qionglai-Sangyuanchang-Guankouchang-Wuzhongshan. The reservoir is distributed in the T2l43in vertical, consists of3-7reservoirs, thickness between10and80meters.Summarizing the above analysis, we pick the area around Gaojiachang-Wuzhongshan,Pengzhou-Dayi as the most favorable exploration zone.