高位钻孔瓦斯抽采参数的优化

Optimization of gas extraction parameters drilling in high-level

为防治综采工作面上隅角瓦斯超限,提高瓦斯抽采效率,以平岗煤矿为例对象,依据采动裂隙“O”形圈理论确定高位钻场及钻孔位置,采用COMSOL模拟软件分析钻孔参数对瓦斯抽采效果的影响,优化钻孔参数,并进行现场应用。结果表明:高位钻场位置为煤层上方20 m,钻场间距70 m,压茬长度不小于35 m,钻孔平距不大于37 m;钻孔仰角控制在-3°~6°,钻孔方位角控制在0°~16°,钻孔数量为4;现场应用表明,经钻孔抽采参数优化,抽采瓦斯纯流量由3.8 m^(3)/min提升至8.1 m^(3)/min;钻孔抽取瓦斯浓度由17.53%增加到45.99%,工作面上隅角瓦斯浓度由0.94%下降到0.33%,工作面瓦斯浓度由0.88%减少到0.27%,回风巷瓦斯浓度由0.83%下降到0.24%。

This paper is an attempt to prevent and control the gas overrun in upper corner of the fully mechanized mining face and improve the gas extraction efficiency drilling in high level.The study taking Pinggang coal mine as an example involves determining the high-level drilling field and drilling position according to the mining-induced fracture"O"ring theory,analyzing the influence of borehole parameters on the gas extraction effect by using COMSOL simulation softwar,optimizing the drilling parameters and conducting on-site application.The research results show that the high-level drilling field is around 20 m′s high above the coal seam,70 m′s spacing of the drilling field,no less than 35 m′s length of the stubble,and no more than 37 m′s horizontal distance of the borehole.The elevation angle of the borehole should be controlled at-3°-6°,the azimuth angle of the borehole should be controlled at 0°-16°,and the number of boreholes should be 4.The application results show that the pure flow rate of gas extraction increases from 3.8 m^(3)/min to 8.1 m^(3)/min by the borehole extraction parameter optimized.The gas concentration extracted by drilling increases from 17.53%to 45.99%,the gas concentration in the upper corner of the working face decreases from 0.94%to 0.33%,the gas concentration in the working face decreased from 0.88%to 0.27%,and the gas concentration in the return airway decreases from 0.83%to 0.24%.