Open Access

ARTICLE

Screening of Coalbed Methane Desorption Enhancers Based on Multiscale Characterization and Their Mechanistic Effects on Methane Desorption Behavior

Xinjun Jiang^1,2, Renyi Qiu^3,*, Xiaofeng Wei^1,2, Xudong Liu^1,2, Kunlun Liu^1,2, Congjiang Ran^1,2, Ruibing Yan^1,2, Yunjin Wang^4,*
1 CHN Energy Group Xinjiang Energy Chemical Co., Ltd., Urumqi, China
2 Xinjiang Coal Mining Dynamic Disaster Prevention and Control Engineering Technology Research Center, Urumqi, China
3 China Coal Research Institute, Beijing, China
4 National Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum Beijing, Beijing, China
* Corresponding Author: Renyi Qiu. Email: ; Yunjin Wang. Email:
(This article belongs to the Special Issue: Enhanced Oil and Gas Recovery in Unconventional ReservoirsⅡ)

Energy Engineering https://doi.org/10.32604/ee.2026.088418

Received 03 July 2026; Accepted 19 August 2026; Published online 10 September 2026

Abstract

To improve methane desorption efficiency in complex deep coal seams, this study evaluated three surfactant-based desorption enhancers—sodium dodecylbenzene sulfonate (SDBS), cetyltrimethylammonium chloride (CTAC), and alkyl polyglucoside (APG)—using deep coal samples from the Ordos Basin. A multiscale characterization framework integrating low-field nuclear magnetic resonance (LF-NMR), surface tension and contact angle measurements, low-temperature N₂/CO₂ adsorption, and scanning electron microscopy (SEM) was established to identify desorption responses, interfacial regulation, pore-structure evolution, and morphological changes. The results show that all surfactants significantly reduced solution surface tension, with SDBS exhibiting the strongest interfacial activity, decreasing surface tension to 23.1 mN/m. LF-NMR T₂ spectra further revealed that the short-relaxation signal attenuated most markedly after SDBS treatment, indicating its superior ability to promote the release of adsorbed or strongly confined methane (This refers to methane that exists in an adsorbed state under the influence of coal pore-surface interactions and confinement within micro- and nanopores. In low-field nuclear magnetic resonance (LF-NMR) measurements, this methane mainly corresponds to the short-T₂ relaxation component of the T₂ spectrum). Pore-structure characterization demonstrated that SDBS enhanced micropore accessibility and improved mesoporous diffusion pathways, as evidenced by increased CO₂ and N₂ adsorption capacities. SEM observations also showed more open pore-fracture structures and weakened surface blockage after SDBS treatment. These results suggest that SDBS promotes methane desorption through interfacial regulation, adsorbed methane release, enhanced pore accessibility, and improved diffusion pathways. This study provides an experimental basis for selecting efficient desorption enhancers and offers technical support for deep coalbed methane recovery.

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Keywords

Gas desorption; desorption enhancer; surfactant; low-field nuclear magnetic resonance; pore structure

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