采用薄片法 ,研究了牛 2 0断块Es3 中a～f砂层组微观裂缝的发育特征 .结果表明 ,砂岩组中存在层理缝和构造缝 ,前者多发育在泥质粉砂岩内和粉细砂岩与泥质粉砂岩层分界线部位 ,构造缝多为张剪裂缝 ,呈雁行式排列 ,多与层理斜交 .对储层裂缝张开度、裂缝率、裂缝渗透率及其分布频率等参数的统计分析认为 ,f砂层组物性优于d ,e砂层组 ,Es3中a～f砂层组储集层类型属于裂缝 -孔隙型 ,按储层裂缝和基质块体的孔隙度、渗透率的大小 ,又可将该储层细分为微裂缝型亚类和潜裂缝型亚类 . The results show that the sandstone group has stratigraphic seams and structural seams, the former mostly developed in the silt siltstone and powder The boundary between fine sandstone and muddy siltstone is mostly Zhang Shek cracks, which are arranged in anagraphic order and obliquely intersect with the bedding.According to the parameters such as the fracture opening degree, the fracture rate, the fracture permeability and their distribution frequency The statistical analysis shows that the properties of f sand layer are superior to those of d and e sand layer, and the reservoir types of a-f sand layer in Es3 belong to the fracture-pore type. According to the porosity and permeability of reservoir fractures and matrix blocks, The rate of size, but also the subdivision of the reservoir into micro-fracture sub-class and latent fracture sub-class.