Pore Structure and Pore Types of Shales

Microstructures of shales exhibit a high degree of complexity and heterogeneity. Nanometer- to micrometer-scale pore systems have been found in the organic matter and matrix of inorganic grains of shale reservoirs, which have significant influence on gas storage and fluid transportation. To elucidate the complex pore systems of shales, various methods have been developed for investigating the pore structure of shales. The fluid invasion methods, such as high-pressure mercury intrusion (MICP) methods, low-pressure gas adsorption, helium pycnometer, provide an estimation of petrophysical properties of shales, including porosity, specific surface area, and pore size distribution.