低渗透性煤层注水数值模拟与工程应用

Numerical Simulation and Engineering Application of Water Injection in Low Permeability Coal Seam

基于Comsol Multiphysics 5.4模拟软件对不同煤体特征参数与注水工艺参数对低渗透性煤体的力学特性和湿润效果的影响规律进行模拟分析,并将模拟结果应用于工程实际。模拟结果显示,注水压力越大,距钻孔距离越小,孔隙压力就越大,三者之间存在一定数学关系,注水压力对湿润半径呈指数式增长趋势;注水孔长度对湿润效果基本无影响;而孔隙度越大,煤体孔隙压力越小,煤体钻孔水质量流量和湿润半径越大,一定范围内煤体更加湿润。应用结果表明,采用数值模拟对湿润半径进行预测可以对工程现场低渗透性煤层的注水工艺参数设计提供引导。现场应用发现煤体的湿润性及工作面的降尘效果显著,对粉尘的产生及控制均起到积极影响,有效改善了井下工作环境。

Based on Comsol Multiphysics 5.4 simulation software,the influences of different coal characteristic parameters and water injection process parameters on the mechanical properties and wetting effect of low permeability coal were simulated and analyzed,and the simulation results were applied to engineering practice.The simulation results showed that the greater the water injection pressure and the smaller the distance from the borehole,the greater the pore pressure,and there was a certain mathematical relationship between the three,and the water injection pressure had an exponential growth trend on the wetting radius;the length of the water injection hole had basically no effect on the wetting effect;while the greater the porosity,the smaller the pore pressure of the coal body,the greater the coal body borehole water mass flow rate and wetting radius,and the coal body was more wetted within a certain range.The application results showed that the prediction of wetting radius by numerical simulation could provide guidance for the design of water injection process parameters of low permeability coal seam in the engineering site.The field application found that the wetting of the coal body and the dust reduction effect of the working face were remarkable,which had a positive impact on the generation and control of dust and effectively improved the underground working environment.