摘要
为揭示煤岩变形对煤层瓦斯抽采渗流特性的影响,开展了煤层瓦斯抽采气固耦合问题研究。首先,考虑煤吸附解吸变形、孔隙压力及渗透性变化对瓦斯抽采的影响;然后,根据达西定律,建立以有效应力及吸附应变为耦合媒介的煤层瓦斯渗流和煤岩变形气固耦合方程;最后,以沙曲矿24208工作面为工程背景进行抽采煤层位移、吸附应变和瓦斯渗流数值模拟,并对比分析煤层瓦斯压力、煤层渗透率和瓦斯抽采量的耦合效应。结果表明:抽采后钻孔周围煤体位移呈增大趋势,煤体因瓦斯解吸收缩变形,距抽采孔越近应变量越大;抽采初期煤层瓦斯压降梯度大;煤层渗透率随抽采时间呈增大趋势,距孔越近增幅越大;初期钻孔瓦斯抽采量较大但降幅较快,后趋于稳定,对比发现模型抽采量计算结果与实际抽采数据较为一致。
In order to reveal the influence of coal deformation on the seepage law of gas drainage,a study on the gas-solid coupling law of coal seam gas drainage was carried out.Considering the changes in coal adsorption deformation,pore pressure and permeability,and assuming that the gas migrates by Darcy flow,a gas-solid coupling equation of coal seam gas seepage and coal deformation with effective stress and adsorption strain as the coupling medium was established.Taking the field conditions as the background,numerical simulation was carried out on the displacement,adsorption strain and gas seepage in the drainage coal seam,and the coupling effect of gas pressure,permeability and gas drainage volume was compared and analyzed.The results show that the displacement of the coal seam around the borehole increases after drainage,the coal body shrinks and deforms due to gas desorption,and the closer it is to the drainage hole,the greater the strain;the gas pressure drop gradient in the coal seam at the initial stage of drainage is larger;after drainage,the coal seam permeability shows an increasing trend,the closer it is to the borehole,the greater the increase.Gas drainage volume in the initial borehole is larger but the decrease is faster,and then tends to stable.Compared with the actual drainage volume,the model calculation results are more consistent with the actual drainage data.
作者
张磊
王浩盛
袁欣鹏
谷超
ZHANG Lei;WANG Hao-sheng;YUAN Xin-peng;GU Chao(College of Coal Engineering,Shanxi Datong University,Datong 037003,China)
出处
《煤炭工程》
北大核心
2022年第7期104-108,共5页
Coal Engineering
关键词
瓦斯抽采
耦合模型
渗透性
吸附应变
gas drainage
coupled model
permeability
adsorption strain
