Methane adsorption-induced coal swelling measured with an optical method

作     者：Tang Shuheng Wan Yi Duan Lijiang Xia Zhaohui Zhang Songhang 

作者机构：School of Energy Resources China University of Geosciences Asia-Pacific Department Petro China Research Institute of Petroleum Exploration & Development 

出 版 物：《International Journal of Mining Science and Technology》 (矿业科学技术学报（英文版）)

年 卷 期：2015年第25卷第6期

页      面：949-953页

核心收录：

学科分类：081702[工学-化学工艺] 0709[理学-地质学] 0819[工学-矿业工程] 0808[工学-电气工程] 081704[工学-应用化学] 07[理学] 08[工学] 070302[理学-分析化学] 0817[工学-化学工程与技术] 0818[工学-地质资源与地质工程] 0708[理学-地球物理学] 0807[工学-动力工程及工程热物理] 0815[工学-水利工程] 0813[工学-建筑学] 0703[理学-化学] 0814[工学-土木工程] 

基　　金：funded by the National Key Technology Support Program of China (No. 2014BAC18B02) the National Natural Science Foundation of China (Nos. 41272176 and 41202116) 

主　　题：CoalAdsorptionMethaneSwellingPermeability 

摘      要：In order to quantify the effect of matrix shrinkage on reservoir permeability during coalbed methane production, coal samples from Huozhou, Changzhi and Jincheng areas in Shanxi province （classified as high-volatile bituminous coal, low-volatile bituminous coal and anthracite, respectively） were collected, and adsorption-induced coal swelling in methane were determined by an optical method at 40 ℃ and pressure up to 12 MPa. All three coals showed similar behavior-that swelling increased as a function of pressure up to about 10 MPa but thereafter no further increase in swelling was observed. Swelling in the direction perpendicular to the bedding plane is greater than that parallel to the bedding plane, and the differences are about 7.77-8.33%. The maximum volumetric swelling ranges from 2.73% to 3.21 %-increasing with increasing coal rank. The swelling data can be described by a modified DR model. In addition, swelling increases with the amount of adsorption. However, the increase shows a relatively slower stage followed by a relatively faster stage instead of a linear increase. Based on the assumption that sorption-induced swelling/shrinkage of coal in methane is reversible, the permeability increases induced by coal shrinkage during methane desorption was analyzed, and the results indicate that the permeability change is larger for higher rank coal in the same unit of pressure depletion.