西湖凹陷西部斜坡带储层成岩作用及孔隙演化

以大量岩心观察为基础，结合室内电镜扫描和物性特征分析，对西部斜坡带储层成岩序列与孔隙演化进行了研究，认为储层岩石类型主要为长石岩屑砂岩及岩屑长石砂岩，储集空间以粒间溶孔和粒内溶孔为主，属中孔中渗一低孔低渗型储层。成岩作用及孔隙演化对储层物性有重要影响，该区主要经历了压实、胶结、溶解以及交代等多种成岩作用，其中压实作用和交代作用对储层起破坏作用，溶解作用对储层改善起建设性作用。成岩阶段可划分为早成岩A期、B期和晚成岩A1期、A2期及B期，目前储层处于晚成岩A2期，原生孔隙大部分被破坏，次生孔隙发育，并在2900～3200m和3600。4000m处形成两个次生孔隙发育带。

Diagenesis and reservoir porosity evolution of Western Slope Zone of Xihu Sag

The main types of reservoir rocks in the Western Slope Zone are feldspathic lithic sandstone and lithic arkose sandstone ,and reservoir space is dominated by the intergranular and intragranular dissolution pores. Bases on core observation, combining with scanning transmission electron microscope and physical property analysis, it is realized that diagenesis and pore evolution have exerted great effects on the properties of reservoir. Study results showed that the reservoir has experienced complex diagenetie events, including com- paction, cementation, dissolution and replacement. The diagenetis stage can be divided into early diagenetic A and B stage and lately diagenetic A1, A2 and B, and now reservoir has entered into A2 stage. Most primary pores were destroyed after diagenetic evolution, and it is mainly secondary pores now. The two secondary dissolved porous belts have formed, one between 2 900 and 3 200 meters deep, and the other between 3 600 and 4 000 meters deep.