海相页岩储层微观孔隙体系表征技术及分类方案

Characterizing Techniques and Classification Methods for Microscope Pore System in Marine Shale Reservoir

页岩储层作为一种非常规油气储集体,对其孔隙体系的研究备受重视。通过充分调研和系统总结国际上关于页岩储层微观孔隙体系的研究现状,综述了孔隙表征技术并指出了存在问题;以客观性和普适性为基础提出了两套分类方案;定性探讨了孔隙演化的一般规律。目前最常见定性观测页岩储层孔隙的方法为高分辨率电子显微镜结合氩离子抛光技术,聚焦离子束扫描电镜系统(FIB-SEM)和纳米CT技术可用于孔隙三维模型重构。高压压汞法结合气体吸附法用于定量分析页岩孔隙结构特征,此外核磁共振也是有效测试手段。分别根据孔隙发育位置与岩石基质关系以及孔隙发育成因与岩石基质关系,将页岩储层孔隙划分为粒间孔、粒内孔、有机质孔和微裂缝以及骨架矿物孔、黏土矿物孔、有机质孔和微裂缝。无机矿物成岩作用与有机质热成熟作用是控制页岩储层孔隙演化的重要因素。

Microscope pore system in unconventional shale reservoir has drawn much attention from the public in recent years.On the basis of investigation of recent research results about shale pore system,pore characterization techniques and pore classification methods are respectively overviewed,and the existing questions are also pointed out.Moreover,the mechanism of pore evolution is qualitatively illustrated.Numerous modern characterization methods for shale pore have been introduced,which include visual observation of pores with high resolution electronic microscope,Ar-ion-milling,FIB-SEM,nano-CT,and quantitative measurements with mercury porosimetry,low pressure gas adsorption analyses and NMR.According to the relationship between pore location and rock matrix,the shale pore system is divided into inter-particle pore,intra-particle pore,organic pore and micro-fracture.Additionally,the shale pore system can also be classified into skeleton minerals pore,clay minerals pore,organic pore,and micro-fracture based on the relationship between pore forming mechanism and rock matrix.The evolution of shale pore is controlled by the process of diagenesis and hydrocarbon generation.