大直径定向钻孔高效成孔钻进技术应用

为了提高寺河煤矿工作面上隅角和回风瓦斯的治理效果，根据工作面顶板覆岩地质特征及开采条件，在煤层上覆顶板岩层内施工顶板高位大直径定向钻孔，依据经验公式确定了顶板大直径高位定向钻孔布置层位。针对顶板硬岩大直径定向钻孔施工过程中先导定向钻孔钻进及分级扩孔效率低的问题，将冲击螺杆马达、扭力冲击器与双级双速扩孔钻具分别应用于定向先导孔与扩孔施工，以提高顶板高位大直径定向钻孔整体施工效率。应用效果表明：冲击螺杆马达成孔技术与扭力冲击旋转扩孔技术提速效果显著，最高钻进速率分别为13.6m/h和11.1m/h，最终形成的200mm大直径高位定向长钻孔保证了钻孔轨迹在煤层顶板裂隙带内有效延伸，实现了对采动卸压瓦斯的持续稳定抽采，取得了良好的瓦斯抽采和治理效果，平均单孔瓦斯抽采量达到3.36m/min，单孔瓦斯瞬时最大抽采量可达26.0m/min。

Technology and application of large diameter directional drilling in high position of roof

In order to improve the control effect of the upper corner and the return air gas of the coal face, large diameter directional borehole is constructed in the coal seam overlying roof slate layer. According to the geological characteristics and mining conditions of roof overburden in working face of Sihe coal mine, and based on the empirical formula, the high-level directional long borehole arrangement layer of roof is determined. Aiming at the problems of low efficiency about pilot directional drilling and graded reaming in the construction of large diameter directional borehole in roof hard rock, the impact screw motor, torsional impactor and two-stage and two-speed reaming drilling tools are respectively applied to pilot borehole construction and reaming construction which can improve the entirety construction efficiency of roof high large diameter directional drilling. The application results in Sihe coal mine show that the drilling efficiency of impact screw motor and graded reaming technology was improved significantly. The maximum drilling rates were respectively 13.6m/h and 11.1m/h. The large diameter and high-level directional long drill hole of Ф 200mm can ensure the effective extension in the seam roof fracture zone and realize the continuous and stable extraction of mining pressure relief gas, which has been obtained good gas extraction and control results, the average gas drainage flow of a single hole can reach more than 3.36m3/min and the instantaneous maximum gas extraction capacity of a single hole can reach 26.0m3/min.