牛20断块储层微观裂缝的发育特征及其类型

Development features and types of microfractures of reservoir in Niu 20 faulted block

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 .

By thin section observation of rock slice, this paper considered that there are two kinds of microfractures in a～f sandstone layers of S 3m of Niu 20 fault block, they are bedding fractures and structural fractures. Bedding fractures mainly developed in argillaceous siltstone and in the contact place between argillaceous siltstone and fine sandstone. Structural fractures arrange in en echelon, are mainly extensional and shear fractures, make friends with bedding. Through the statistics analysis of fracture aperture fracture permeability ,distribution frequency of reservoir, this paper considered the type of a～f sandstone layer of S 3m in Niu 20 fault block to be the type of fracture～pore. According to the matrix of reservoir and the relation between fracture porosity and permeability, this paper divided the sabtype of fracture, They are microfractures and potential fractures.