The nanopore network in organic-rich shale plays a key role in shale gas storage and migration, and micropores are an important structural unit in connecting the migration channel. In this study, we selected six non-marine coal-bearing shales from the Qinshui Basin to investigate the
effect of composition on micropore structure using X-ray diffraction, total organic carbon (TOC), vitrinite reflectance, and CO2 adsorption methods. The results indicate that non-marine shale with higher TOC content possesses more micropores, leading to a more complex pore structure
and improving the heterogeneity of shale reservoirs. With the increase in TOC content, the micropore surface area and micropore volume clearly increases, which greatly improves the gas storage space in shale reservoirs. The thermal evolution of organic matter promotes the development of micropores
to a certain extent in non-marine shale. Clay minerals possess a rough surface and develop more micropores, and their influence on the micropore structure of non-marine shale is relatively strong, while terrestrial quartz exhibits significant micropore development. The obviously positive correlations
between micropore volume and kaolinite, chlorite contents in the non-marine shale suggest that kaolinite and chlorite make a certain contribution to micropore volume. The characteristics of micropore structures in coal mainly depend on lithotypes, TOC content, and ash content, while clay content,
quartz content, and TOC content are the key factors controlling the formation of micropores in non-marine shale.
Lithofacies characteristics and its effect on gas storage of the Silurian Longmaxi marine shale in the southeast Sichuan Basin, China
