胜坨油田二区沙河街组二段（Ｅｓ２）三角洲储层以中细砂岩、粉砂岩为主，储层的埋藏较浅，成岩作用较弱，常见压实、胶结和溶解作用，粘土矿物的转化作用也较普遍，属于早成岩期的Ｂ亚期。储层的粒间孔隙发育，以中孔中细喉结构为主，孔喉参数变化范围较大，储层成岩和孔隙结构的非均质性较强。注水开发加大了不同相带的砂体成岩和孔隙结构的差异，进一步增强了储层的非均质性 Es2 reservoirs in the second member of Shahejie Formation in Block II of Shengtuo Oilfield are dominated by fine sandstone and siltstone. The reservoirs are shallow buried with weak diagenesis and common compaction, cementation and dissolution. The clay minerals Transformation is also more common, belonging to the B diagenesis period. The intergranular pores of the reservoirs develop mainly in the mid-pore throat, with a wide range of pore-throat parameters. The diagenesis and pore structure of the reservoir are highly heterogeneous. Waterflooding has increased the diagenesis and pore structure of sandstone bodies with different facies belts and further enhanced reservoir heterogeneity