ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Georeservoirs
Volume 13 - 2025 | doi: 10.3389/feart.2025.1609857
Effect of pore structure on methane adsorption characteristics in tectonically deformed coals
Provisionally accepted
- 1University of Chinese Academy of Sciences, Beijing, China
- 2Qingdong Coal Mine Huaibei Min Co Ltd, huaibei, China
- 3State Key Lab Coal & Coalbed Methane Comining, jincheng, China
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The regulation of pore structure on methane adsorption and free state in tectonically deformed coals directly affects the efficiency of coalbed methane extraction and coal mine safety.In this paper, we systematically characterised the full-size pore structure of different deformed coals (primary, brittle and ductile) in Huaibei mining area by integrating mercury intrusion, lowtemperature nitrogen adsorption, carbon dioxide adsorption and methane isothermal adsorption, quantified the pore dynamics evolution law by combining with the fractal theory, and resolved the adsorption mechanism. The results show that: (1) The coal mainly consists of micropores (17.0~45.9 %) and macropores (46.8~76.9 %), with fewer mesopores (1.6~7.3%). With the intensification of tectonic deformation, the volume of micropores and macropores increased by 0.013 cm³ /g and 0.097 cm³ /g, and the specific surface area increased by ~40 m² /g and <2 m² /g. Fractal analysis showed that macroporous complexity (D₁) decreased while microporous complexity (D₃) increased during ductile deformation; (2) microporous parameters (volume, specific surface area) dominated methane adsorption capacity (R² >0.7), while macroporous enlargement (up to 0.108 cm³ /g) exacerbated the risk of free methane enrichment; (3) Brittle deformed coal is suitable for coalbed methane development due to microporous optimisation, while ductile deformed coal requires enhanced gas prevention and control due to free gas enrichment in large pores. The study reveals the dynamic correlation mechanism of 'pore evolution, adsorption/free gas and disaster risk' under the tectonic deformation gradient, which provides theoretical support for the efficient development and safe exploitation of coalbed methane.
Keywords: tectonically deformed coal, Pore structure, methane adsorption, Coalbed methane, Deformation characterization
Received: 11 Apr 2025; Accepted: 19 May 2025.
Copyright: © 2025 Wang, Ju, Ren, Li, Xiao, Wang, Gao and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yiwen Ju, University of Chinese Academy of Sciences, Beijing, China
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