致密砂岩储层微观孔隙结构特征及物性影响因素分析——以延长探区上古生界山西组为例  

Microscopic pore structure characteristics and its effects on reservoir quality: A case study from Shanxi formation of upper Paleozoic in Yanchang exploration area in Ordos Basin

作　　者：尚婷[1] 曹红霞[1] 郭艳琴 吴海燕[1] 强娟[1] 武渝 高飞 罗腾跃[1] 

机构地区：[1]延长石油(集团)有限责任公司研究院,陕西西安710069 [2]西安石油大学地球科学与工程学院,陕西西安710065

出　　处：《西北大学学报（自然科学版）》2017年第6期877-886,共10页Journal of Northwest University（Natural Science Edition）

基　　金：国家科技重大专项基金资助项目(2011ZX05044;2011ZX05001-004)

摘　　要：在岩心观察的基础上,根据大量的岩石薄片、扫描电镜和阴极发光镜下的观察和统计,运用图像粒度和高压压汞分析,探讨鄂尔多斯盆地山西组砂岩储层微观孔隙结构的特征及物性影响因素。研究结果表明,研究区除局部存在受裂缝影响发育的高孔渗段外,整体孔隙度与渗透率呈正相关;山1段物性较山2段好,整体孔隙不发育,物性较差;孔隙和吼道的大小及连通性直接决定着物性的好坏,表现出典型的致密砂岩型气藏。在沉积相中,水下分流河道较分流河道间的孔隙度和渗透率好。研究区以发育岩屑石英砂岩和岩屑砂岩为主,其次为石英砂岩,石英砂岩的孔渗物性整体较好,岩屑石英砂岩次之,岩屑砂岩最差;砂岩的粒度越粗,孔隙越发育,物性越好。在经历了强烈的压实作用后,硅质胶结及晚期形成的碳酸盐胶结是储层致密、物性差的主要原因。黏土矿物中,伊利石、高岭石和混层类的充填胶结作用是影响渗透率的关键性因素。石英颗粒表面绿泥石薄膜保护了原生粒间孔隙,而本区有限的溶蚀作用对储层起到一定程度的改善作用。该研究对在上古生界大面积低丰度天然气藏的背景下,发现"甜点式"的油气富集区具有重要的理论意义和实际指导意义。Based on the core observation,analyses on lug data of casting thin sections,SEM,cathode luminescence,image size,high pressure Hg injection,mercury and etc,the microscopic pore structure characteristics and its effects on reservoir quality were studied. The result shows that the porosity and permeability were positively correlated unless the cracks affect the development of high permeability,and the Shan 1 reservoir physical property is a little better than that of the Shan 2. The overall pore doesn't develop and has poor physi-cal property. The size and connectivity of the pore and roar lines determine the quality of the reservoir. The study area shows the typical tight sandstone reservoir gas reservoirs. The distributary channel sandstone reservoir is better than inter-distributary bay. The layer rock is mainly lithic quartz sandstone,lithic sandstone and quartz sandstone. The final physical properties is generally better than the former,and the latter is relatively poor. The high permeability reservoir has big particle size with pore development. Compaction is the general background of reservoir densification,siliceous cementation and late carbonate cementation are the main cause of densification. Cemetation of illite,kaolinite and illite-smectite are the main controlling factors of permeability. A great quantity chlorite thin film formation on detrital grains have resulted in significant primary intergranular pores preserved,and limited dissolution has a certain degree of improvement to the reservoir porosity and permeability. The above results are of significance both in theory and practice for tracing "sweet spots"in natural gas-bearing reservoir as well.

关 键 词：微观孔隙结构 上古生界 山西组 延长探区 

分 类 号：TE122.2[石油与天然气工程—油气勘探]