In China, the exploration and development of low-rank coalbed methane (CBM) resources are in the early stage, and in-situ pyrolysis is an effective technology for mining of low-rank CBM resources. In this paper, N₂ adsorption method and high-pressure mercury injection test were used to study the pore structure characteristics of coal samples by water vapor injection, and the pore size boundaries of the two test methods were determined. From the continuous pore space distribution model, Frenkel–Halsey–Hill model, Menger sponge model, a new method of pore size classification is proposed: (I) (> 10,000 nm), (II) (1000–10,000 nm), (III) (100–1000 nm), (IV) (x (pore diameter boundary)–100 nm), (V) (10–x nm), (VI) (< 10 nm). The results were not inconsistent with the Hodot classification method, indicating that the new pore classification scheme is reliable. Meanwhile, the relationship between pyrolysis temperature and matrix compressibility is discussed, and it was found that transition pores had a significant effect on matrix compressibility. Pyrolysis weakened the connection between coal particles, improved the development of porosity, and led to high matrix compressibility. Furthermore, when pyrolysis temperature was < 400 °C and matrix compression effect was dominant, poor pore connectivity resulted in a low level of matrix compressibility; when pyrolysis temperature was > 500 °C and pore filling effect was dominant, high level of matrix compressibility was promoted.

我国低阶煤层气（CBM）资源勘探开发尚处于起步阶段，原位热解是低阶煤层气资源开采的有效技术。本文采用N ₂吸附法和高压压汞试验研究了水蒸气注入煤样的孔隙结构特征，确定了两种试验方法的孔径边界。从连续孔隙空间分布模型、Frenkel-Halsey-Hill 模型、Menger 海绵模型，提出了一种新的孔径分类方法：(I) (> 10,000 nm), (II) (1000–10,000 nm), (III ) (100–1000 nm), (IV) ( x (孔径边界)–100 nm), (V) (10– x nm), (VI) (< 10 nm)。结果与Hodot分类方法没有矛盾，表明新的孔隙分类方案是可靠的。同时，讨论了热解温度与基体压缩率的关系，发现过渡孔隙对基体压缩率有显着影响。热解削弱了煤颗粒之间的联系，改善了孔隙度的发展，并导致高的基质压缩性。此外，当热解温度<400 ℃且基体压缩效应占主导地位时，孔隙连通性差导致基体压缩性低；当热解温度> 500 ℃且孔隙填充效应占主导地位时，促进了高水平的基质压缩性。