Guodong QiaoZegong LiuYongmin ZhangChangping YiKui GaoShigui FuYouzhi Zhao
School of Safety Science and Engineering, Anhui University of Science and TechnologyInstitute of Energy, Hefei Comprehensive National Science CenterSchool of Electrical Engineering, Xi’an Jiaotong UniversityDivision of Mining and Geotechnical Engineering, Luleå University of Technology
Coalbed methane (CBM) is a significant factor in triggering coal and gas outburst disaster, while also serving as a clean fuel. With the increasing depth of mining operations, coal seams that exhibit high levels of gas content and low permeability have become increasingly prevalent. While controllable shockwave (CSW) technology has proven effective in enhancing CBM in laboratory settings, there is a lack of reports on its field applications in soft and low-permeability coal seams. This study establishes the governing equations for stress waves induced by CSW. Laplace numerical inversion was employed to analyse the dynamic response of the coal seam during CSW antireflection. Additionally, quantitative calculations were performed for the crushed zone, fracture zone, and effective CSW influence range, which guided the selection of field test parameters. The results of the field test unveiled a substantial improvement in the gas permeability coefficient, the average rate of pure methane flowrate, and the mean gas flowrate within a 10 m radius of the antireflection borehole. These enhancements were notable, showing increases of 3 times, 13.72 times, and 11.48 times, respectively. Furthermore, the field test performed on the CSW antireflection gas extraction hole cluster demonstrated a noticeable improvement in CBM extraction. After antireflection, the maximum peak gas concentration and maximum peak pure methane flow reached 71.2% and 2.59 m3/min, respectively. These findings will offer valuable guidance for the application of CSW antireflection technology in soft and low-permeability coal seams.
CSW antireflection in coal seamsCBM extraction enhancementSoft and low-permeability coal seamsField test
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会