关键词: 深层页岩气, 沉积演化, 有机孔, 斜坡-陆棚, “高有机碳-高灰质”页岩, 吴家坪组, 茅口组, 中上二叠统, 川东红星地区

Abstract: Based on tectonic，core and logging data，a systematic analysis was conducted on the sedimentary evolution，reservoir characteristics and shale gas enrichment models of Middle-Upper Permian shale in Hongxing area of eastern Sichuan Basin by means of electron microscope scanning，low-temperature N₂ adsorption experiments，high-pressure mercury pressure experiments and basin simulation，the favorable exploration areas were identified，the exploration results and significance were summarized. The results show that：（1）The sedimentary evolution of Middle-Upper Permian in Hongxing area is characterized by open platform facies in QixiaMaokou Formation；platform-shelf facies at the bottom of the fourth member of Maokou Formation，with fast facies change，while slope-shelf facies at the top of the fourth member of Maokou Formation，with strata denuded， thicker in the south and thinner in the north；marine-terrestrial transitional coastal swamp-lagoon facies at the bottom of the first member of WujiapingFormation，while platform-slope-shelf facies at the top of the first member of WujiapingFormation，with small distribution and fast facies change；slope-shelf facies in the second member of WujiapingFormation，which was controlled by paleoclimate，volcanic activity，paleoclimate，and volcanic activity from early to late，with high paleoproductivity during the middle to late sedimentary periods and average TOC greater than 8.00%.（2）Two sets of high-quality shales were developed in the shelf facies areas in the fourth member of Maokou Formation and the second member of Wujiaping Formation，with high organic carbon and high calcite content. Their thicknesses of organic-rich shales are 19 m and 25 m，respectively. The pores are dominated by organic pores，and the structures are mainly micropores and mesopores. The thinly interbedded mixed shale phases of carbon-rich tuff and the thinly interbedded siliceous shale phases of high carbon tuff are high-quality phases，with porosity of 6.27% and 6.43%，TOC of 10.11% and 9.35%，gas saturation 92.59% and 91.81%，and brittleness index of 55.24% and 61.19%，respectively. They are the dual“sweet spots”of geology and engineering.（3）The widely developed Permian stratified algae in the study area are the main source of organic matters. During the mian hydrocarbon expulsion period of Jurassic，the tectonic was stable，with less hydrocarbon expulsion of Permian hydrocarbon source rocks. Middle Jurassic to the early stage of Early Cretaceous was the main gas generation period，with weak tectonic activity and good preservation conditions for shale gas. The gas generation process has been completed and is currently in the mature to over mature stage，with a R_o value of about 2.1%，indicating huge exploration potential.（4）Jiannan，Longjuba and Sanshing blocks are favourable exploration areas，with Jiannan block having the greatest potential. The third sublayer of the fourth member of Maokou Formation and the third layer of the second member of Wujiaping Formation are target-window layer segments of high-quality layers.

Key words: deep shale gas, sedimentary evolution, organic pore, slope-shelf, high organic carbon-high calcite content shale, Wujiaping Formation, Maokou Formation, Middle-Upper Permian, Hongxing area in eastern Sichuan Basin