摘要
通过岩心观察和测井资料分析、铸体薄片鉴定、扫描电镜观察和储层的物性数据统计。研究了鄂尔多斯盆地中部山2段砂岩储层的特征。，结果表明：山2段砂岩以石英砂岩和岩屑石英砂岩为主．储集空间以剩余原生粒间孔、粒间溶孔为主，储渗能力主要依赖于基质孔隙，属于低孔、低渗型储层；储层发育受沉积相、砂体粒度、物质组分及成岩作用综合控制。曲流河三角洲前缘水下分流河道和河口坝微相砂岩为最有利于储层发育的沉积相带；砂岩粒度、石英含量及碎屑组成是储层品质发育优劣的基础：成岩作用对储层具有双重控制作用。不同成岩环境决定了各类成岩作用的强弱。在酸性环境下硅质-高岭石胶结及溶蚀作用有效改善储层孔隙结构及孔渗性能。强压实作用及碱性环境下的硅质-碳酸盐-伊利石胶结等减少大量孔隙。对各砂层组进行分析对比，山2^3砂层组以细-中粒石英砂岩为主，其成分和结构成熟度高，岩屑含量相对较低-以酸性环境下形成的硅质-高岭石胶结为主，发育剩余粒间孔和高岭石晶间孔，是有利砂层组。
The characteristics of sandstone reservoirs of the Shan2 Member in the middle part of Ordos basin are studied through core observation, well logging data analysis, casting thin section identification, scanning electron microscope observation and reservoir physical data statistics. The results show that the sandstone of the Shah2 Member is mainly quartzose sandstone and lithic quartzose sandstone. The reservoir spaces are mainly residual primary intergranular pores and intergranular dissolved pores. And the percolation capacity of the reservoirs mainly depends on the permeability of the matrix, being reservoirs with low porosity and low permeability. The reservoirs development was controlled comprehensively by the sedimentary facies, granularity of sand body, material composition, and diagenesis. The sandstone of meandering river delta front underwater distributary channel and mouth bar microfacies is the sedimentary facies that is the most favorite for reservoir development. The granularity, quartz content, and detrital or clastic composition of the sandstone is the basis of the development of the reservoir quality. Diagenesis has dual control on the reservoirs. Different diagenetic environments determine the strength of all kinds of diagenesis. In the acidic environment, the cementation and dissolution of siliceous- kaolinite can effectively improve the pore structure and permeability of the reservoirs. A large number of pores are reduced by the strong compaction and the siliceous-carbonate-illite cementation in an alkaline environment. Through comparative analysis of various sand group, the Shan23 sand group is mainly composed of fine-mid grains of quartzose sandstone, with high maturity of composition and structure, relatively low content of detritus, and mainly siliceous-kaolinite cementation formed in the acidic environment. Residual intergranular pores and kaolinite intercrystalline pores are developed in the Shan2^3 sand group, being favorable one.
关键词
储层特征
鄂尔多斯盆地
山2段
致密砂岩
reservoir characteristics
Ordos Basin
Shan2 Member
tight sandstone
