基于COMSOL Multiphysics模拟的瓦斯抽采钻孔合理间距研究

为考察坪上煤业主采3号煤层的合理抽采钻孔间距，利用瓦斯在煤层中的运移和渗流规律，结合实测煤的参数条件，在相同的抽放负压、抽放时间等影响条件下，运用COMSOL Multiphysics有限元软件模拟了不同钻孔间距时所抽煤层在抽采时间为400 d时钻孔影响范围内煤体瓦斯含量变化规律，得出了满足抽采时间条件下的合理钻孔间距为5 m。结合矿井2305（上）回采面巷道内开展了不同钻孔间距实测，在相同的瓦斯地质参数及抽采系统条件下，连续抽采且观测时间达到400 d时各钻孔的瓦斯抽采纯量和钻孔浓度变化。确定了在抽采时间达到400 d时，抽采钻孔间距为5 m时的钻孔瓦斯浓度为35%、流量为0.04 m3/min，受抽采系统影响明显；而间距在6 m的钻孔的流量和浓度仍保持自然衰减特征。模拟和现场实测均验证了该矿瓦斯抽采钻孔间距布置以5 m最佳，该研究为实际生产过程中确定合理的钻孔间距提供理论依据，为矿井瓦斯抽采布局及瓦斯治理提供了技术保障。

Research on reasonable spacing of gas drainage boreholes based on COMSOL Multiphysics simulation

In order to investigate the reasonable spacing of the boreholes in No.3 coal seam of Pingshang Coal Industry，the article used the law of gas migration and seepage law in coal seam，combined with the parameters of measured at the scene，under the influence of the same negative pressure and drainage time，this paper simulated the law of coal gas content in the affected area of the different spacing of the borehole when the extraction time was 400 d by using the COMSOL Multiphysics of the finite element software.It was concluded that the reasonable borehole spacing was 5 m when the pumping time was satisfied.Combining with the measure of the different distance between boreholes in the face of the 2305（upper） mining face，under the same gas geological parameters and drainage system conditions，the time of continuous extraction and observation reached 400 d，variation of net volume and borehole concentration of gas drainage in each borehole，it was determined that drilling effect of drilling was affected obviously by pumping system when the 400 d extraction time was reached，the borehole concentration and flow rate were 35% and 0.04 m3/min respectively when drilling 5 m，while the flow and concentration of boreholes still maintain natural attenuation characteristics when the 6 m distant of the drill hole.Both the simulation and field measurements verify that the spacing of gas drainage boreholes was the best in 5 m.This study provides theoretical basis for reasonable borehole spacing in actual production process，and provides strong technical guarantee for gas drainage layout and gas control in mine.