遂宁—蓬溪地区须二段是重要的天然气储层，目前已显示出良好的勘探前景，但由于该砂岩储层具 有低孔、低—特低渗以及非均质性强等特点，直接影响了油气的勘探开发。 通过薄片、扫描电镜、包裹体 温度、镜质体反射率、有机质热降解温度等资料，对该区须二段储层成岩作用类型、强度及孔隙演化史进 行了系统研究。 结果表明：该砂岩储层经历了中等—强压实、强胶结、弱交代、强溶蚀等成岩作用；目前处 于中成岩阶段 A—B 亚期，且在 A 亚期末储层已基本致密化；孔隙类型以次生孔隙为主。 通过对砂岩储 层致密化进程的深入阐述，可为该地区有利储层发育区的预测提供一定的地质依据。

Sandstone of the second member of Xujiahe Formation is an important natural gas reservoir with good exploration prospect in Suining-Pengxi area. The low porosity, low permeability and strong heterogeneity of the sandstone reservoir directly affected the oil and gas exploration and development in this area. Based on slice observation, SEM, inclusion thermometry, vitrinite reflectance and thermal degradeation, this paper systematically studied the types and intensity of diagenesis and porosity evolution of the second member of Xujiahe Fomation. The results show that the sandstone has undergone medium-strong compaction, strong cementation, weak metasomatism and strong corrosion. The reservoir is currently in the middle diagenetic A-B stage and the reservoir was almost completely compacted at middle diagenetic A stage. The pore type is mainly secondary pore. This paper provided geological evidence for favorable reservoir developing area via clear illustration of the process of sandstone reservoir compaction.