Full‐Scale Pore Structure Characterization of the Late Permian Dalong Shale in Western Hubei, Southern China

The Late Permian Dalong Formation in western Hubei has recently been recognized as a promising target for shale gas development. However, the comprehensive characterization of its pore structure remains limited. To elucidate the pore system of the Dalong shale, an integrated experimental approach was applied to outcrop‐derived samples. The analytical techniques utilized included total organic carbon (TOC) analysis, vitrinite reflectance (Ro) measurement, X‐ray diffraction (XRD), helium porosimetry, field emission scanning electron microscopy (FE‐SEM), low‐pressure CO 2 and N 2 adsorption, and mercury intrusion porosimetry (MIP). The results show that the Dalong shale is rich in organic matter (OM) and brittle minerals and has reached an overmature evolutionary stage, with organic pores serving as its main reservoir space type. The total pore volume (PV) of the Dalong shale ranges from 0.0081 to 0.0443 cm 3 /g, which is mainly contributed by pores with a diameter of less than 10 nm; the total specific surface area (SSA) varies from 13.23 to 91.86 m 2 /g, with pores smaller than 2 nm in diameter being the primary contributor. TOC shows a positive correlation with pores smaller than 10 nm, whereas no significant statistical correlation exists between mineral composition and macropore volume for the studied samples. This study comprehensively reveals the pore structure characteristics of the Dalong shale in western Hubei at the microscopic scale, providing a scientific basis for the precise evaluation and development of shale gas resources in the subsequent exploration of the Dalong Formation.