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靖边气田二叠系砂岩储层的低孔低渗特征成为严重困扰该区天然气生产的关键问题,为了分析该区储层物性变差的主要原因,提高储层预测精度,本文通过系统的薄片鉴定、压汞、阴极发光、扫描电镜等分析,研究了该区砂岩的成岩作用及其对储集性能的控制作用。研究发现,靖边气田盒8段砂岩主要为岩屑砂岩、岩屑石英砂岩和石英砂岩,胶结物主要为碳酸盐、高岭石、绿泥石和硅质胶结,碳酸盐胶结物含量对储层物性影响较大;储集空间主要是剩余原生粒间孔、粒间溶孔、粒间溶蚀扩大孔、粒内溶孔、高岭石晶间孔及少量微裂缝,以次生孔隙为主;盒8段砂岩主要为II、III类储集岩,I类储集岩较少。研究认为,沉积微相奠定了储层的物质基础,决定储层的空间展布,而成岩作用改造是储层物性好坏的关键因素,二者共同决定了储层的发育程度。压实作用和胶结作用是储层物性变差的最主要原因,广泛发育的铝硅酸盐矿物溶解对储层物性的改善起关键作用。
The low porosity and permeability characteristics of Permian sandstone reservoirs in Jingbian Gas Field are the key issues that seriously plague the natural gas production in this area. In order to analyze the main reason for the deterioration of reservoir physical properties in this area and to improve the reservoir prediction accuracy, Diagenesis, mercury intrusion, cathodoluminescence and scanning electron microscopy. The diagenesis of sandstone and its controlling effect on reservoir performance were studied. The results show that the sandstone of box 8 in Jingbian gas field is mainly composed of lithic sandstone, lithic quartzite sandstone and quartz sandstone. The cements are mainly composed of carbonate, kaolinite, chlorite and siliceous cements. The content of carbonate cements The physical property of reservoirs has a great influence on the reservoir properties. The reservoir space mainly consists of residual primary intergranular pores, intergranular dissolution pores, intergranular dissolution and expansion pores, intragranular dissolution pores, kaolinite intergranular pores and a few micro-cracks. The main sandstone of box 8 is mainly type II and III reservoir rocks, while type I reservoir rock is less. The study suggests that the sedimentary microfacies laid the material foundation of reservoirs and determined the spatial distribution of reservoirs, and the diagenesis transformation is the key factor of reservoir physical properties. Both of them determine the development degree of reservoirs. Compaction and cementation are the main reasons for the poor reservoir physical properties. The extensive development of aluminosilicate minerals plays a key role in the improvement of reservoir physical properties.