鄂尔多斯盆地长7段致密储层微观特征研究

针对鄂尔多斯盆地致密油储层特征复杂，缺乏系统研究的问题，通过大量岩芯观察，分析化验数据统计，同时采用恒速压汞实验、场发射及CT扫描等高分辨率测试手段和方法，对长7致密油储集层形成和特征进行了研究，认为延长组长7段致密油储集体由牵引流和重力流沉积的致密砂岩形成，具有粒度细，储层厚度大，脆性指数高，储层物性差等特征。孔隙类型以粒间孔和长石溶孔为主，可见孔隙含量低，主要发育微米-纳米级孔隙，喉道以片状和管状为主，受黏土矿物和有机质充填，有效孔隙体积小，但微裂缝发育，连通性好，储层含油层物性下限低，可动流体饱和度高。

A Study on Microscopic Pore Characteristics of Tight Reservoir of Chang 7 Sedimentation Section of Yanchang Formation,Ordos Basin

There lacks systematic research into the complex characteristics of tight oil reservoir in Ordos Basin. By means of core observation, test data analysis, constant speed mercury injection experiment, field emission and CT scanning etc., we studied the formation and characteristics of Chang 7 tight oil reservoir. The research suggests that tight oil reservoir consists of tight sandstone formation of traction current and gravity flow deposits of Chang 7 section of Yanchang formation, which is of poor reservoir property with fine granularity, thick reservoir, high brittleness,. Pore types are mainly intergranular pores and feldspar dissolved pores which are mainly micro-nano-scale pores with flake-shaped and tube-shaped throats; due to the filling of clay minerals and organic matter, effective pore volume is small, but micro cracks are highly developed and are of good connectivity; lower limit of oil reservoir physical property is low, and fluid saturation is high.