Diffusion-Osmosis Characteristics of Coalbed Methane in Tectonically Deformed Coals and Their Mechanism
- 责任者：Chen Fuyong (Geological Survey Department of Anhui Huaibei Mining Croup Company ; Huaibei 235000 ; China) ; Ju Yiwen
- 刊名：Earth Science Frontiers
- 出版年：2010
- 卷期：17（1)
- 关键词：构造煤 ; tectono-coal ; 煤层气 ; coalbed gas
- 页码：p.195-201
- 图表：4 illus., 2 tables, 20 refs.
- 分类号：1003
- issnNo：ISSN1005-2321
- isbnNo：CN11-3370/P
There are three stages for the production of coalbed methane: desorption, diffusion and osmosis. The diffusion process of methane and multi-component gases in the deformed coals is not consistent with that in primary coals. The change of external pressure is only an external factor in the whole process of adsorption- desorption in tectonically deformed coals; the essential factors of the process are the deformation, the change of structure and the adsorption potential. Those factors are the root causes which induce the irreversible process of desorption. When the balance of coal and multi-gas like CH4 has been destroyed, the tectonically deformed coals that deformed stronger shows a phenomenon of hysteresis of desorption after the pressure reduced, and the gas in weakly deformed coal will desorb quickly. The process of desorption has two phases: one is the gas desorption and the other is the process of free gas from micropores diffusing to the bigger pores; the latter one determines the gas diffusion rate.