Microscopic Pore Structure Characteristics and Genesis of Low Resistivity Reservoirs: A Case Study of the Wufeng and Longmaxi Formations in the Changning Area, Sichuan Basin

ABSTRACT This study investigates the micro‐pore structure characteristics and genesis of low‐resistivity reservoirs in the Wufeng and Longmaxi Formation of the Sichuan Basin. A comprehensive analytical approach—combining core analysis, gas adsorption, high‐pressure mercury intrusion, and X‐ray photoelectron spectroscopy (XPS) was employed to systematically characterize the pore structure of low‐resistivity shale reservoirs and their relationship with electrical resistivity. The results reveal that low‐resistivity shale reservoirs typically exhibit smaller pore volume and specific surface area, along with a higher degree of organic matter graphitization. This organic matter graphitization process significantly reduces the rock's resistivity. Pore structure evolution is governed by both compaction and tectonic deformation, leading to macropore reduction and meso‐/micropore redistribution. Morphological transformations in organic matter pores—including pore collapse and wall contact—further facilitate electron migration and contribute to resistivity decline. By analyzing microstructural features of the Wufeng–Longmaxi shale, this study highlights the dominant influence of organic matter maturity, graphitization, and pore structure dynamics on resistivity, offering a theoretical framework for understanding the genesis and guiding exploration of low‐resistivity shale gas reservoirs.