A small-scale experimental study of CO_(2) enhanced injectivity methods of the high-rank coal

作     者：Qing-He Niu Li-Wen Cao Shu-Xun Sang Wei Wang Wei Yuan Jiang-Fang Chang Xiao-Jun Jia Wei-Min Zheng Zeng-Xue Zhang Qing-He Niu;Li-Wen Cao;Shu-Xun Sang;Wei Wang;Wei Yuan;Jiang-Fang Chang;Xiao-Jun Jia;Wei-Min Zheng;Zeng-Xue Zhang

作者机构：State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering StructuresShijiazhuang Tiedao UniversityShijiazhuang050043China Hebei Technology and Innovation Center on Safe and Efficient Mining of Metal MinesShijiazhuang050043China School of Resource and Earth ScienceChina University of Mining and TechnologyXuzhou221008China Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and UtilizationChina University of Mining and TechnologyXuzhou221008China Hebei Academy of Emergency ManagementShijiazhuang050081China Hebei Iron and Steel Group Mining Co.LtdTangshan063000China Minmetals Mining Holding Co.LtdHefei241000China 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2021年第18卷第5期

页      面：1427-1440页

核心收录：

学科分类：0820[工学-石油与天然气工程] 08[工学] 082002[工学-油气田开发工程] 

基　　金：sponsored by the National Natural Science Foundation of China(Grant nos.41727801,41972281,51979170,11902208,U1967208 and 41330638) the National Key Research and Development Plan Project of China(2018YFB0605600) the Natural Science Foundation of Hebei Province(E2021210077) the Autonomous subject of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures(ZZ2020-29) Science and Technology Research Project of Hebei Province Colleges and Universities(QN2021129) 

主　　题：Supercritical CO_(2) Permeability Intermittent injection N_(2)displacing CO_(2) Pre-fracturing 

摘      要：The attenuation of CO_(2)injectivity has become the biggest technical barrier for the application of CO_(2)enhanced coalbed methane recovery(CO_(2)-ECBM).Commonly,the intermittent CO_(2)injection,N2 displacing CO_(2)and pre-fracturing are the potential CO_(2)enhanced injectivity methods for coal reservoirs,but their mechanism and effectiveness remain to be *** paper thus conducted small-scale experiments to simulate the working process of these engineering measures by an independently developed experimental *** show that the CO_(2)injectivity of coal is remarkably improved by the intermittent injection mode since the CO_(2)injection time is increased by folds and the loss of reservoir pressure can be complemented in *** N_(2)displacing CO_(2)method promotes the desorption of CO_(2)and reduces the swelling strain,with the result that the permeability of coal is improved by 74.82%and 64.95%compared with the methods of the primary subcritical CO_(2)(Sub CO_(2))and supercritical CO_(2)(Sc CO_(2))***,the permeability reduces again with the secondary CO_(2)*** permeability of the coal sample after pre-fracturing is averagely improved by 1-2 orders of magnitude,the irreversible permeability loss rate,average stress sensitivity coefficient and the permeability loss rate due to adsorption are averagely reduced by 95.885%,61.538%and 96.297%,*** indicates that the permeability of coal after pre-fracturing is no longer sensitive to both the effective stress and Sc CO_(2)adsorption,the injectivity is thus improved and *** CO_(2)enhanced injectivity effects of the intermittent CO_(2)injection,the N_(2)displacing CO_(2)and the pre-fracturing are various,which thus can be selected individually or jointly to improve the CO_(2)injectivity according to the reservoir physical properties and geological *** research deepens the understanding of the functional mechanism of CO_(2)enhanced injectivity method