镇泾地区长8致密砂岩储层成岩作用研究

鄂尔多斯盆地镇泾地区三叠系延长组长8储层为典型的致密低渗透砂岩储层。为了明确有利储层的控制因素,运用铸体薄片鉴定、阴极发光及扫描电镜等测试方法,对该区长8储层的成岩作用类型及特征进行了研究。结果表明：该区砂岩经历的成岩作用主要为压实作用、胶结作用以及溶蚀作用;成岩演化阶段处于中成岩阶段A期;成岩作用控制着该区储层物性,强烈的机械压实作用和碳酸盐胶结作用是破坏储层物性的主要因素;颗粒表面的绿泥石环边保护了原生粒间孔隙;在成岩作用后期,长石的弱溶蚀形成的次生孔隙改善了储层物性。

Study on diagenesis of Chang 8 tight sandstone reservoir in Zhenjing area

The sand of Chang 8 reservoir of Upper Jurassic Yanchang Formation in Zhenjing area belongs to tight and low permeability reservoir. Based on the analysis of cast thin section, cathodeluminescence and scanning electronic microscope, this paper studied the characteristics and types of diagenesis of Chang 8 reservoir. The results show that the sandstone reservoir in this area mainly experienced compaction, cementation and dissolution, the diagenetic evolution reached the middle diagenetic stage A, and reservoir physical properties were controlled by digenesis. Mechanical compaction and carbonate cementation are the major destructive diagenesis, the chlorite rim on the grain surface plays a constructive role in protecting primary intergranular pores, and the secondary pores created by dissolution of feldspar improve the reservoir properties.