Characterization of Full-Sized Pore Structure and Fractal Characteristics of Marine–Continental Transitional Longtan Formation Shale of Sichuan Basin, South China

Abstract

Despite the recent significant progress reviewed in marine and continental shale gas reservoirs, there is no general investigation concerning marine–continental transitional shales, especially in the research of the pore structure and fractal characteristics of marine–continental shale reservoirs. In this study, the pore structure characteristics of 12 typical marine–continental transitional shale samples of the Upper Permian Longtan Formation collected from Southern Sichuan Basin were analyzed, combining techniques of total organic carbon (TOC) content determination, X-ray diffraction, field emission scanning electron microscopy, high-pressure mercury intrusion porosimetry, and low-pressure N2/CO2 adsorption. And the pore fractal characteristics of shales were also analyzed using the Frenkel–Halsey–Hill model with N2 adsorption data. Not only the effects of TOC content and mineralogical compositions for pore structure parameters and fractal dimensions were analyzed but also the relationships between pore...