近距离煤层群高位定向长钻孔瓦斯抽采实践

Gas Drainage by High Position Directional Long Borehole in Close Distance Coal Seam Group

为有效解决青龙煤矿21602工作面采煤期间上隅角瓦斯浓度超限问题,利用定向钻进技术的轨迹可控、覆盖区域广等优势,在21602工作面布置高位定向长钻孔抽采采动卸压瓦斯。介绍了高位定向长钻孔瓦斯抽采技术原理,分析了钻孔布置层位及设计方案,通过现场实践确定了21602工作面高位定向长钻孔优先布置在顶板距离煤层16~28 m区域。实践表明,21602工作面采煤期间上隅角瓦斯浓度由抽采前的最高值0.72%降低到抽采期间的0.20%~0.40%,单孔抽采瓦斯纯流量达1.58 m 3/min,有效保证了工作面的高效安全回采,可为近距离煤层群上隅角瓦斯治理提供经验。

In order to effectively solve the problem of gas over limit in the upper corner of coal mining in 21602 working face in Qinglong Coal Mine,with the advantage of controllable trajectory and wide coverage area of directional drilling technology,the high directional long borehole was arranged in 21602 working face to extract the pressure relief gas.This paper introduced the technical principle of gas extraction by high directional long borehole,analyzed the layout and design scheme of the borehole.Through field practice,it was determined that the long directional borehole should be arranged preferentially in the range of 16 m to 28 m from roof to coal seam in 21602 working face.The drainage effect shows that the gas concentration in the upper corner of 21602 working face is reduced to the range from 0.20%to 0.40%,which is up to 0.72%before the extraction,the single-hole gas extraction is 1.58 m 3/min.It effectively guarantees the efficient and safe mining of the working face,and provides experience for the gas control in the upper corner of close distance coal seam group.