鄂尔多斯盆地环县西部地区延10储层特征及影响因素分析

Analysis of the characteristics and influencing factors of the Yan 10 reservoir in the western region of Huanxian,Ordos Basin

为了研究鄂尔多斯盆地环县西部地区延10储层特征,通过铸体薄片、扫描电镜以及圧汞分析等实验分析方法,对环县西部地区侏罗系延10储层特征及影响因素进行了系统研究。结果表明,区内延10储层主要岩石类型为长石岩屑砂岩和岩屑砂岩,填隙物主要由黏土矿物胶结物和硅质胶结物组成;孔隙度为5.02%~19.07%,渗透率为0.15×10^(-3)~1 176.80×10^(-3)μm^(2),为中-低孔隙度、中-低渗透率的常规碎屑岩储层;储集空间类型以粒间孔、长石溶孔以及晶间孔为主,孔隙结构以Ⅰ类和Ⅱ类为主;区内主要发育辫状河沉积体系,中部主河道及主河道交汇处储层物性最好,有利储层主要分布于心滩沉积微相区域;储层物性主要受沉积作用和成岩作用影响,强烈的压实作用以及黏土矿物胶结物、硅质胶结物、碳酸盐胶结物的形成是使储层孔隙度降低的主要原因,而绿泥石膜的形成以及长石和岩屑的溶解则有利于改善储层物性条件;区内延10段储层已达中成岩阶段A期。

In order to study the characteristics of Yan 10 reservoir in the western region of Huanxian,Ordos Basin,a systematic study was conducted through experimental analysis methods such as casting thin sections,scanning electron microscopy,and mercury pressure analysis.The results show that the main rock types of the Yan10 reservoir in the study area are feldspar lithic sandstone and lithic sandstone,and the interstitial material is mainly composed of clay mineral cement and siliceous cement.The porosity ranges from 5.02% to 19.07%,and the permeability ranges from 0.15×10^(-3)μm^(2) to 1 176.80×10^(-3) μm^(2),which belongs to the conventional clastic rock reservoir with medium low porosity and medium low permeability.The main types of reservoir space are intergranular,feldspar dissolution and intergranular pores,and the pore structure is mainly of type I and II.Braided river sedimentary system is mainly developed in the study area.The physical property in the middle main river channel and the intersection of main river channel is the best,and favorable reservoirs are mainly distributed in the central beach sedimentary micro-facies area.The physical property is affected by sedimentation and Diagenesis and other factors.The strong compaction in the region and the formation of clay mineral cement,siliceous cement and carbonate cement are the main reasons for the decrease of reservoir porosity,while the formation of Chlorite group film and the dissolution of feldspar and rock debris are conducive to improving reservoir physical conditions.The reservoirs in the Yan10 member of the study area have reached the middle diagenetic stage A stage.