Coal matrix deformation characteristics in the process of carbon dioxide displacing different gas saturation coal-bed methane  

作　　者：Xiao-Ming NI Quan-Zhong LI Yan-Bin WANG Sha-Sha GAO 

机构地区：[1]School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China [2]State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, China [3]College of Geo-science and Surveying Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China

出　　处：《Journal of Coal Science & Engineering(China)》2013年第3期303-308,共6页煤炭学报（英文版）

摘　　要：It is fundamental that changes in coal reservoir permeability are researched, in particular, the accurate determination of variations in the coal matrix caused by CO2 replacing CH4 at different gas saturation conditions. Based on the surface free energy, the extended Langmuir isothermal adsorption model, combined with CO2 replacing CH4 in experimental trials, and calling on the more general principles and characteristics of the field, mathematical models describing the coal matrix as it undergoes different processes such as CO2 injection and desorption were established. Combined with laboratory data about CO2 replacement under different methane saturation conditions, a law governing the variations in coal matrix CO2 replacement under different methane gas saturation conditions was obtained. The results showed that： in the injection process, the coal matrix expansion rate caused by CO2 or CH4 was exponentially increased with the CO2 pressure increase, the expansion caused by CO2 was far greater than the expansion caused by CH4 in the desorption process, the coal matrix shrinkage caused by CO2 or CH4 was exponentially increased with the pressure decrease, the shrinkage caused by CO2 was larger than the shrinkage caused by CH4 under the same pressure and different gas saturation, the total shrinkage in the desorption process in the coal matrix was greater than the total expansion in the injection process. At higher gas saturations, the total coal matrix shrinkage volume exceeded the total expansion corresponding to pressure points higher in the desorption process.

关 键 词：carbon dioxide coal matrix adsorption swelling desorption contraction 

分 类 号：TQ116.3[化学工程—无机化工] P618.11[天文地球—矿床学]