By means of thin section analysis, zircon U-Pb dating, scanning electron microscopy, electron probe, laser micro carbon and oxygen isotope analysis, the lithologic features, diagenetic environment evolution and controlling factors of the tight sandstone reservoirs in the Huagang Formation of Xihu sag, East China Sea Basin were comprehensively studied. The results show that: the sandstones of the Huagang Formation in the central inverted structural belt are poor in physical properties, dominated by feldspathic lithic quartz sandstone, high in quartz content, low in matrix, kaolinite and cement contents, and coarse in clastic grains; the acidic diagenetic environment formed by organic acids and meteoric water is vital for the formation of secondary pores in the reservoirs; and the development and distribution of the higher quality reservoirs in the tight sandstones of the Huagang Formation are controlled by sediment source, sedimentary facies belt, abnormal overpressure and diagenetic environment evolution. Sediment provenance and dominant sedimentary facies led to favorable initial physical properties of the sandstones in the Huagang Formation, which is the prerequisite for development of reservoirs with better quality later. Abnormal high pressure protected the primary pores, thus improving physical properties of the reservoirs in the Huagang Formation. Longitudinally, due to the difference in diagenetic environment evolution, the high-quality reservoirs in the Huagang Formation are concentrated in the sections formed in acidic diagenetic environment. Laterally, the high-quality reservoirs are concentrated in the lower section of the Huagang Formation with abnormal high pressure in the middle-northern part; but concentrated in the upper section of Huagang Formation shallower in burial depth in the middle-southern part.

通过薄层分析，锆石U-Pb定年，扫描电镜，电子探针，激光微碳氧同位素分析，西湖凹陷花岗组致密砂岩储层的岩性，成岩环境演化及控制因素。 ，对东海盆地进行了全面研究。结果表明：中部倒置构造带花岗组砂岩物性较差，以长石质片状石英砂岩为主，石英含量高，基体，高岭石和水泥含量低，碎屑粒粗；由有机酸和大气水形成的酸性成岩环境对于在储层中形成次生孔隙至关重要。花岗组致密砂岩中优质储层的发育和分布受沉积源，沉积相带，超压异常和成岩环境演化的控制。沉积物源和主要的沉积相使得花岗组砂岩具有良好的初始物理性质，这是后来开发优质储层的前提。异常高压保护了初级孔隙，从而改善了花岗组储层的物理性质。纵向上，由于成岩环境演化的差异，花岗组优质储集层主要集中在酸性成岩环境形成的剖面中。侧面地 优质油藏集中在华岗组下部，中北部异常高压。但集中在花岗组上部，中南部中部埋藏深度较浅。