摘要
为解决深部煤层瓦斯压力大、含量高的问题,以平岗煤矿为研究对象,依据采动裂隙椭抛带基本性质,采用COMSOL软件优化了瓦斯抽采钻孔间距,分析了优化后方案的抽采效果,并进行现场验证.结果表明:随着瓦斯抽放,钻孔周边瓦斯压力降低较快,渗透系数也随之降低,钻孔间距设置为1m时,抽采效果最优;优化后,与未抽采时相比,抽采50d到100 d时,抽采口处的瓦斯压力降低了5×104 Pa,而抽采 250 d到300 d时,瓦斯压力仅降低了1×104 Pa,总体瓦斯抽采效果比较明显;现场监测结果显示,回采工作面高含量瓦斯层位基本处在距煤层顶板16、19 和 22m左右位置,钻孔距"O形圈"越近,裂隙发育越完整,瓦斯含量越高,抽采效果越好.
Abstract
This paper aims to address the problems of high gas pressure and high gas content in deep coal seam.The study,by taking Pinggang Coal Mine as the research object,consists of optimizing the spacing of gas extraction holes by using COMSOL software based on the basic properties of mining fracture ellipsoid zone,analyzing the extraction effect of the optimized scheme;and conducting the field verifica-tion.The results show that with the gas drainage,the gas pressure around the borehole decreases rapidly,and the permeability coefficient also decreases,and the optimal extraction effect appears with the spacing of boreholes by 1 m.After optimization,the overall gas extraction effect is more obvious,compared with the non-pumping condition,the gas pressure at the extraction port decreases by 5×104 Pa from 50 d to 100 d,while the gas pressure only decreases by 1×104 Pa from 250 d to 300 d.The field monitoring re-sults show that the high-content gas layer of the mining face is basically located at about 16,19 and 22 m away from the coal seam roof.The closer the borehole to the"O-ring",it follows the more complete the fracture development,the higher the gas content,and the better the extraction effect.
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