Effects of organic-inorganic transformation and interaction on the occurrence of nanopores within the organic-rich shale during thermal maturation: Insights from the hydrous pyrolysis experiments in a closed system

作者：Yong Tang, Chuxiong Li, Hong Cheng, Suyang Cai, Xiao Li, Qilin Xiao, Menglin Zheng, Jin Pan · 发表于：Petroleum Science · 年份：2025 · DOI：10.1016/j.petsci.2025.02.024 · 被引用次数：5 · 研究领域：Hydrocarbon exploration and reservoir analysis、Coal Properties and Utilization、Petroleum Processing and Analysis

The organic-inorganic transformation and interaction act as the critical role in the occurrence of nanopores within the organic-rich shales during thermal maturation. Hydrous pyrolysis experiments were conducted on the organic-rich mudrock collected from the Upper Cretaceous Nenjiang Formation of the Songliao Basin, China in a closed system. The pore types and pore network, and organic and inorganic compositions of pyrolyzed shales were detected from the early to over mature stages (% R o = 0.61–4.01). The experimental results indicate that geochemical transformation of organic matters and minerals and the interaction control the formation and evolution of nanoporosity. In oil window mineral matrix pores are infilled by the generated oil, K-feldspar dissolution by organic acids promotes clay illitization to form illite, and the catalytic effects of clays (e.g. illite) in the complex of organic matter and clays may promote the in-situ retained oil cracking to generate natural gas, resulting in the early occurrence of organic-matter pores in the complex within oil window. Due to significant primary cracking of solid kerogen to generate extractable liquid oil, pore volume for storing fluids presents a persistent increase and approaches the maximum at the end of oil window. In gas window intensive oil cracking facilitates the hydrocarbon migrating out of the source home and pyrobitumen formation, resulting in the significant occurrence of modified mineral matrix pores and organic...