Structure and Fractal Characteristics of Organic Matter Pores in Wufeng–Lower Longmaxi Formations in Southern Sichuan Basin, China

作者：Quanzhong Guan, Dazhong Dong, Bin Deng, Cheng Chen, Cheng Li, Kun Jiao, Yuehao Ye, Haoran Liang, Huiwen Yue · 发表于：Fractal and Fractional · 年份：2025 · DOI：10.3390/fractalfract9070410 · 被引用次数：3 · 研究领域：Hydrocarbon exploration and reservoir analysis、Geochemistry and Geologic Mapping、NMR spectroscopy and applications

Organic matter pores constitute a significant storage space in shale gas reservoirs, contributing to approximately 50% of the total porosity. This study employed a comprehensive approach, utilizing scanning electron microscopy, low-pressure N2 adsorption, thermal analysis, image statistics, and fractal theory, to quantitatively characterize the structure and complexity of organic matter pores in the Wufeng–lower Longmaxi Formations (WLLFs). The WLLFs exhibit a high organic matter content, averaging 3.20%. Organic matter pores are typically well-developed, predominantly observed within organic matter clusters, organic matter–clay mineral complexes, and the internal organic matter of pyrite framboid. The morphology of these pores is generally elliptical and spindle-shaped, with the primary pore diameter displaying a bimodal distribution at 10~40 nm and 100~160 nm, potentially influenced by the observational limit of scanning electron microscopy. Shales from greater burial depths within the same gas well contain more organic matter pores; however, the development of organic matter pores in deep gas wells is roughly equivalent to that in medium and shallow gas wells. Fractal dimension values can be utilized to characterize the complexity of organic matter pores, with organic matter macropores (D>50) being more complex than organic matter mesopores (D2–50), which in turn are more complex than organic matter micropores (D<2). The development of macropores and mesopores is a k...