Abstract The different responses of vitrinite and inertinite to thermal metamorphism strongly affect the evolution of nanopores in different macerals of coal reservoirs. In order to reveal these differences during coalification, vitrinite and inertinite samples were handpicked from 10 block coal samples. A series of laboratory experiments were performed to explore the macromolecular structure and nanopores of the samples. The results indicate that the nanopore structure of the vitrinite showed obvious regularities with the reflectance of vitrinite (in oil, Ro), but that of the inertinite did not. The macromolecular structure of the inertinite did not correlate with Ro, whereas the vitrinite showed obvious correlations with Ro. Therefore, the nanopore structure of the inertinite cannot be affected by changes in Ro. The nanopore structures of both the vitrinite and inertinite were affected by the changes of macromolecular structures. The detachment of the aliphatic side chains and the promotion of the aromatic degree and the aromatic ring polycondensation degree decreased the micropore surface area (micro-SA) because the longer aliphatic side chains and lower degree of aromatic ring polycondensation make the surface of the coal particle more heterogeneous. The increases in the aromatic degree and aromatic ring polycondensation degree increased the mesopore volume (Vmes), total pore volume excluding micropores (VT), mesopore surface area (meso-SA), and Brunauer–Emmett–Teller (BET) specific surface area (BET-SA) because more isolated pores were connected with each other; thus, more interspace emerged among the aromatic ring layers with an increase in Ro. However, this does not mean that these regularities of inertinite are related to the coal rank, because macromolecular structures of the inertinite had been fixed prior to the coal formation and is not sensitive to coalification. These results are expected to enhance the understanding of the differences in vitrinite and inertinite nanopore structure evolution that occurs during coalification.

中文翻译：

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煤化过程中煤层气储层镜质体和惰性体纳米孔演化比较

摘要 镜质体和惰性体对热变质作用的不同反应强烈影响煤储层不同基质中纳米孔的演化。为了揭示煤化过程中的这些差异，从 10 块煤样品中精心挑选了镜质体和惰性样品。进行了一系列实验室实验以探索样品的大分子结构和纳米孔。结果表明，镜质体的纳米孔结构与镜质体（油中，Ro）的反射率表现出明显的规律性，而惰性的反射率则没有。惰性大分子结构与 Ro 无关，而镜质体与 Ro 有明显的相关性。因此，惰性分子的纳米孔结构不会受到 Ro 变化的影响。镜质体和惰性体的纳米孔结构均受大分子结构变化的影响。脂肪侧链的脱离以及芳香度和芳香环缩聚度的提高使微孔表面积（micro-SA）降低，因为脂肪侧链越长，芳香环缩聚度越低，使煤颗粒表面更加异类。芳香度和芳环缩聚度的增加增加了中孔体积（Vmes）、不包括微孔的总孔体积（VT）、中孔表面积（meso-SA）和Brunauer-Emmett-Teller（BET）比表面积（ BET-SA)，因为更多的孤立孔相互连接；因此，随着 Ro 的增加，芳环层之间出现了更多的空间。然而，这并不意味着惰性分子的这些规律与煤级有关，因为惰性分子的大分子结构在煤形成之前就已经固定，对煤化不敏感。这些结果有望增强对煤化过程中镜质体和惰性纳米孔结构演化差异的理解。