Numerical description of coalbed methane desorption stages based on isothermal adsorption experiment

Zhang, Zheng, Qin, Yong, Wang, Geoff X. and Fu, XueHai (2013) Numerical description of coalbed methane desorption stages based on isothermal adsorption experiment. Science China-Earth Sciences, 56 6: 1029-1036. doi:10.1007/s11430-013-4597-2

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Author Zhang, Zheng
Qin, Yong
Wang, Geoff X.
Fu, XueHai
Title Numerical description of coalbed methane desorption stages based on isothermal adsorption experiment
Journal name Science China-Earth Sciences
ISSN 1674-7313
Publication date 2013-06
Sub-type Article (original research)
DOI 10.1007/s11430-013-4597-2
Volume 56
Issue 6
Start page 1029
End page 1036
Total pages 8
Place of publication Beijing, China
Publisher Zhongguo Kexue Zazhishe
Collection year 2014
Language eng
Abstract Quantitative description of desorption stages of coalbed methane is an important basis to objectively understand the production of coalbed methane well, to diagnose the production state, and to optimize the management of draining and collection of coalbed methane. A series of isothermal adsorption experiments were carried out with 12 anthracite samples from 6 coalbed methane wells located in the south of the Qinshui Basin, based on the results of isothermal adsorption experiments, and an analytical model was developed based on the Langmuir sorption theory. With the model, a numerical method that adopts equivalent desorption rate and its curve was established, which can be used to characterize the staged desorption of coalbed methane. According to the experimental and numerical characterizations, three key pressure points determined by the equivalent desorption rate curvature that defines pressure-declining desorption stage, have been proposed and confirmed, namely, start-up pressure, transition pressure and sensitive pressure. By using these three key pressure points, the process of coalbed methane desorption associated with isothermal adsorption experiments can be divided into four stages, i.e., zero desorption stage, slow desorption stage, transition desorption stage, and sensitive desorption stage. According to analogy analysis, there are differences and similarities between the processes of coalbed methane desorption identified by isothermal adsorption experiments and observed in gas production. Moreover, it has been found that larger Langmuir volume and ratio of Langmuir constants are beneficial to earlier advent of steady production stage, whereas it is also possible that the declining production stage may occur ahead of schedule.
Keyword Coalbed methane
Isothermal adsorption
Equivalent desorption rate
Desorption stage
Key pressure
Numerical description
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 4 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 8 times in Scopus Article | Citations
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Created: Sun, 14 Jul 2013, 00:14:45 EST by System User on behalf of School of Chemical Engineering