煤田地质与勘探2023，Vol.51Issue(11)：1-12,12.DOI:10.12363/issn.1001-1986.23.04.0161
静态致裂作用下低渗厚煤层瓦斯增透数值模拟研究
Numerical simulations of enhancing permeability and gas extraction of thick coal seams through static fracturing
摘要
Abstract
This study seeks to improve the underground operation efficiency and optimize the borehole arrangement parameters for static fracturing of coal seams.To this end,this study conducted tests in the belt roadway of the No.12316 fully mechanized mining face in the Wangjialing Coal Mine,China Coal Huajin Group.By combining the equa-tions for coal seams'deformation and failure,gas diffusion and seepage,and coal seams'permeability evolution,this study constructed a model of the damage and permeability evolution of coal seams.Based on the numerical simulations of the process of static fracturing and permeability enhancement of coals,as well as its influencing factors,using F1AC3D and COMSOL Multiphysics,this study revealed the laws of the stress distribution,plastic expansion,and gas pressure transfer and evolution of coal seams under the action of static fracturing.Furthermore,through field experiments using fracturing parameters selected through optimization,this study quantitatively analyzed the changes in gas flow extracted from coal seams during static fracturing under different borehole spacings.The following findings are obtained.During the static fracturing,the expansion stress in coals was evenly transferred outward along the radial directions of the bore-hole for fracturing.An annulus stress zone and a plastic zone were formed during single-hole fracturing.In the case of double-hole fracturing,the expansion stress in both holes exhibited better superposition effects in the horizontal direc-tion than in the vertical direction,leading to more significant damage to coals in the horizontal direction than in the ver-tical direction.Furthermore,zones between both holes were damaged earlier than other zones.After permeability and gas extraction were enhanced by static fracturing,the gas pressure and permeability of coal seams were positively and negatively correlated with the hole spacing,respectively due to the limited static fracturing range.During field tests,stat-ic fracturing and permeability enhancement were conducted under hole spacings below 1.6 m.After gas extraction for 30 days under negative pressure of 20 kPa,the pure gas flow extracted after fracturing doubled.This indicates that static fracturing has significant pressure-relief and permeability-enhancement effects on gas extraction.关键词
瓦斯抽采/静态致裂/煤层增透/扩散渗流/数值模拟/效果评价Key words
gas extraction/static fracturing/penetration enhancement for coal seam/diffusion and seepage/numerical simulation/effect evaluation分类
矿业与冶金引用本文复制引用
王新丰,刘文港,王龙,韦友玉,张乔..静态致裂作用下低渗厚煤层瓦斯增透数值模拟研究[J].煤田地质与勘探,2023,51(11):1-12,12.基金项目
国家自然科学基金项目(51904266,52104224) （51904266,52104224）
湖南省自然科学基金青年项目(2023JJ40634) （2023JJ40634）
湖南省教育厅优秀青年基金项目(21B0144) （21B0144）
煤矿安全高效开采省部共建教育部重点实验室开放基金项目(JYBSYS2018203) （JYBSYS2018203）
