Mechanism Affecting the Pore Differentiation Characteristics of Fine-Grained Tight Sandstones: A Case Study of Permian Shanxi Formation in Ordos Basin.

In this study, the pore-throat structure and lithological and fractal characteristics of fine-grained sandstone reservoirs of Permian Shanxi Formation in Ordos Basin are investigated using various experiments, including casting thin section, scanning electron microscopy (SEM), high-pressure mercury injection (HPMI), and nuclear magnetic resonance (NMR). The relation between rock type difference and pore structure difference is explored, and the controlling effect of pore-throat structure on physical properties of fine-grained sandstone reservoir is studied. The results show that the sandstone sample can be categorized into quartz arenites, sublitharenite, and lithic sandstone.