四川盆地中三叠统雷口坡组还未发现规模连片的油气田群,勘探陷入困境,关键问题是其储层形成机制与分布规律认识不清.利用最新的油气勘探成果和丰富的基础资料,从层序地层划分与对比入手,系统梳理和分析了中三叠统的地层分布、沉积与储层特征.研究结果表明:①盆地内存在中三叠统天井山组(亦称"雷口坡组五段"),为中三叠统重要的有利勘探层系之一;②微生物岩为雷口坡组重要的碳酸盐岩类型,具有规模发育和形成规模有效储层的潜力;③准同生期的白云石化和岩溶作用、表生期的岩溶作用是雷口坡组储层成孔的主要控制因素,早埋藏期酸性成岩环境和埋藏期溶蚀作用及构造裂缝是孔隙保持和改善、改造的关键因素;④古隆起周缘的风化壳岩溶分布带、准同生岩溶作用叠加表生岩溶改造的微生物岩与颗粒滩分布带为有利储层发育区带.

Up to now，no large-scale oil or gas field group has been found in Leikoupo Formation of Middle Triassic in Sichuan Basin. The key problem is that the formation mechanism and distribution law of reservoirs are not well understood. Starting from the division and correlation of sequence stratigraphy, the stratigraphic distribution, sedimentation and reservoir characteristics of the Middle Triassic are systematically sorted out and analyzed by using the latest oil and gas exploration results and abundant basic data. The results show that: (1) the Middle Triassic Tianjingshan Formation (also known as "the Leikoupo Formation Member 5") exists in the basin, which is one of the important favorable exploration strata in the Middle Triassic; (2) microbial carbonate rock is an important type of carbonate rock of Leikoupo Formation, which has the potential acting as large-scale effective reservoir; (3) dolomitization and karstification in paracontemporaneous period and karstification in supergene stage are the main controlling factors of reservoir pore forming in Leikoupo Formation, and the acid diagenetic environment in early burial period, dissolution and structural fractures in burial period are the key factors for pore maintenance, improvement and transformation; (4) the distribution zone of weathering crust karst around the paleouplift, and the distribution zone of the microbial rock and granular shoal reformed by paracontemporaneous and supergene karstification are favorable reservoir development zones.