页岩孔隙系统研究实验方法

Experimental Methods for Shale Pore System

基于页岩孔隙系统的特殊性,讨论了FESEM-QEMSCAN、FIB-FESEM、NANO-CT、氮气吸附法、小角中子散射等几种页岩孔隙系统研究方法的特点和适用范围。指出场发射扫描电镜以及与之结合的能谱和矿物定量评价系统(FESEM-QEMSCAN)是研究页岩纳米级孔隙类型、大小、形态以及矿物分布的基础手段;聚焦离子束扫描电镜、微纳米CT可刻画页岩孔隙系统在三维空间的展布特征,利用获得的三维数据体进行数值模拟,可进一步计算孔隙度、渗透率等物性参数;氮气吸附法可对小于100nm的极微孔隙的孔径、形态进行求算;小角中子散射则可利用孔隙中存在的气体分子,获得孔隙系统连通性等重要参数。最后从页岩岩石组构的角度,探讨了页岩孔隙控制因素,指出有机质含量与成熟度,黏土矿物类型、含量,碎屑颗粒的含量以及成岩强度是影响页岩孔隙系统的主要因素。

This paper discusses the experimental methods about FESEM-QEMSCAN, FIB-SEM, NANO- CT, N2-Adsorption and SANS for shale pore systems. Based on the experimental conditions and charac- ters, the kit of FE-SEM, FESEM-QEMSCAN and FIB-FESEM is considered as most useful for the re- search of shale pore, which can extract the structure of shale pore and characterize it, such as the type, size distribution, morphology of shale pore and the shale composition. According to the combination of FIB-FESEM and Nano-CT, the 3D pore structure could be constructed and shale physical properties, po- rosity, permeability and pore size distribution could be obtained through computation modeling. The size and structure of shale pore, size being less than 100 nm, can be computed and predicted by Nz-adsorption. Pore connection can be researched by SANS. The paper has investigated, with a deep discussion, control- ling factors of shale pore, such content and maturity of organic matter, type and content of clay, content of siliceous particle and diagenesis intensity （cement index）.