东海陆架盆地西湖凹陷三潭深凹油气成藏条件较好，已发现Y、Q、G等多个构造，油气资源丰富。该区成藏富集的关键因素是储层，但研究区经历早期深埋，整体物性偏差，“甜点”储层发育区不明，制约了中深层油气勘探进程。为了寻找优质储层规模区，基于岩石薄片、X衍射、物性等资料，通过对三潭深凹南、中、北部储层沉积、微观孔隙结构、成岩演化差异性对比得出2点认识：①储层特征与成岩方面，研究区多为低孔低渗—特低孔特低渗-致密储层，储层演化处于中成岩B期；次生溶孔是主要储集空间类型，绿泥石膜和溶蚀作用是建设性成岩作用。②储层物性差异方面，受物源、成岩作用和地温梯度差异的影响，导致三潭深凹南、北储层致密顶界埋深不同，南部致密储层顶界埋深4 000 m，对应温度140 ℃；中北部致密储层顶界埋深4 700 m，对应温度160 ℃。平湖组比花港组储层经历了较强的碳酸盐胶结、较弱压实和较强溶蚀作用，常规储层段发育更多优质储层，致密储层段受源内超压成岩抑制效应控制，发育有效储层。基于以上认识提出“粗粒相、主河道砂体、源内超压”主控的优质储层发育模式，对西湖凹陷三潭深凹中深层寻找规模油气藏具有重要指导意义。

The Santan Deep Depression in the Xihu Sag of East China Sea Basin has favorable conditions for oil and gas accumulation, and multiple gasfields such as Y, Q, and G have been discovered, indicating abundant oil and gas resources. The key factor for accumulation and enrichment in this area is the reservoir. However, the study area experienced early deep burial, resulting in overall poor reservoir physical properties and unclear distribution of sweet spot reservoirs, which constrains the exploration process of oil and gas in the middle and deep formations. To identify large-scale high-quality reservoir zones, based on data such as thin section observation, X-ray diffraction, and physical properties, two conclusions were drawn through comparison of sedimentation, microscopic pore structures, and differences in diagenetic evolution of reservoirs in the southern, central, and northern parts of the Santan Deep Depression: (1) In terms of reservoir characteristics and diagenesis, the study area mainly consisted of low-porosity and low-permeability, ultra-low-porosity and ultra-low-permeability, and tight reservoirs, with reservoir evolution at the middle diagenetic stage B. Secondary dissolution pores were the main type of reservoir space, and chlorite film and dissolution were constructive diagenesis processes. (2) In terms of differences in reservoir physical properties, influenced by provenance, diagenesis, and geothermal gradient variations, the burial depths of the top boundaries of tight reservoirs between the southern and northern parts of the Santan Deep Depression differed. The top boundary of tight reservoirs in the southern part was buried at 4 000 m, corresponding to a temperature of 140 ℃. In the central and northern parts, the top boundary was at 4 700 m, with a corresponding temperature of 160 ℃. Compared with the Huagang Formation, Pinghu Formation reservoirs experienced stronger carbonate cementation, weaker compaction, and stronger dissolution. More high-quality reservoirs were developed in conventional reservoir units, and more effective reservoirs were developed in tight reservoirs controlled by the overpressure-induced diagenetic inhibition effects within the source. Based on the above understanding, a high-quality reservoir development model controlled by “coarse-grained facies, main channel sand bodies, and internal source overpressure” was proposed, providing important guidance for exploring large-scale oil and gas reservoirs in the middle and deep formations of the Santan Deep Depression in the Xihu Sag.