Evolution of the 3D pore structure of organic-rich shale with temperature based on micro-nano CT

作者：Chaofan Zhu, Tian-Le Zhang, Jun-fan Pan, Yanwei Li, James J. Sheng, Ge Dong, Rui Jia, Wei Guo · 发表于：Petroleum Science · 年份：2025 · DOI：10.1016/j.petsci.2025.03.037 · 被引用次数：18 · 研究领域：Hydrocarbon exploration and reservoir analysis、Coal Properties and Utilization、NMR spectroscopy and applications

Organic-rich shale is a significant potential source of oil and gas that requires development through in situ conversion technology. However, the evolution patterns of the internal three-dimensional (3D) pore structure and kerogen distribution at high temperatures are not well understood, making it difficult to microscopically explain the evolution of the flow conductivity in organic-rich shale at high temperatures. This study utilizes high-resolution X-ray computed tomography (micro-nano CT) to obtain the distribution of pores, kerogen, and inorganic matter at different temperatures. Combined with the pyrolysis results for the rock, the evolution of the pore structure at various temperatures is quantitatively analyzed. Based on three-phase segmentation technology, a model of kerogen distribution in organic-rich shale is established by dividing the kerogen into clustered kerogen and dispersed kerogen stored in the inorganic matter and the pores into inorganic pores and organic pores within the kerogen skeleton. The results show that the inorganic pores in organic-rich shale evolve through three stages as the temperature increases: kerogen pyrolysis (200–400 °C), clay mineral decomposition (400–600 °C), and carbonate mineral decomposition (600–800 °C). The inorganic pores porosity sequentially increases from 3% to 11.4%, 13.1%, and 15.4%, and the roughness and connectivity of the inorganic pores gradually increase during this process. When the pyrolysis temperature reaches 400...