近距离松软煤层群高位钻孔瓦斯抽采技术研究
Study on gas drainage technology with high level borehole in cont iguous soft coal seams group
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摘要: 为解决高应力近距离松软煤层群高位钻孔抽采效果差、工作面上隅角瓦斯超限等问题,利用轨迹测试仪测定钻孔轨迹,并结合对现场高位钻孔参数设计、现场施工、抽采效果的分析,得到了高位钻孔抽采技术中存在的问题,分析了造成高位钻孔抽采效果差的原因,基于此提出了高位钻孔抽采优化方法。结果显示:造成高位钻孔抽采效果不佳的原因为钻孔大幅度偏离设计轨迹及煤孔段堵孔;可通过控制钻进速度、缩短钻孔长度、增加孔径、对煤孔段进行扩孔、下筛管的手段优化抽采设计。对比优化前后高位钻孔抽采效果,发现优化后平均单日抽采纯量提高了3倍,优化抽采效果显著。Abstract: In order to solve the poor gas drainage effect of the high level borehole and the gas over limiat the top corner of the coal mining face and other problems in the high stress and contiguous softcoal seams group,a track inclinometer was applied to measure the borehole track.ln combination with the analysis on the parameter design of the site high level borehole,the siteconstruction and gas drainage effect the problemsexisted in the gas drainage technology of the high level borehole were obtained.The cause to make the poor gas drainage effect of the high leveborehole was analyzed.Based on the circumstances a gas drainage optirmized method of the high level borehole was provided. The results showed that the causes to make the poor gas drainage effect of the high level borehole would be the borehole highly deviated from the designed trackand the borehole seam section blocked.The gas drainage designed could be optimized with the control of the drling speed,reductionof the drlng length ,the borehole diameter increased,borehole reamed at the seam section and screen tube. In comparison the gas drainage efect of the high level borehole before and after the optimization,the daily drainage pure volume in average was highly upgraded by three times afer the optimzation and the optimized gas drainage effect was obvious.