瓦斯抽采钻孔布置方案参数优化： 以保德煤矿为例

针对高瓦斯中低渗透率厚煤层工作面常规预抽钻孔预抽浓度低、钻孔衰减系数大、瓦斯预抽时间长等难题，以保德煤矿8号煤层为研究对象。通过8号煤层渗透率各项异性实验分析和现场测试，对8号煤层钻孔布孔方位以及封孔工艺最优参数进行研究。结果表明：预抽钻孔与煤壁裂隙呈90°,钻孔倾角为-6°时钻孔抽采效果最好；采用新材料+囊袋作为封孔材料，封孔距离8～16 m时，增大压力和“两堵两注”的注浆方式，能有效地提供封孔的气密性。通过3种不同的测试方法，确定4个月时的钻孔抽采有效半径约为4 m, 6个月有效抽采半径为4.5 m。以此为依据，得出工作面瓦斯抽采钻孔最佳布置参数。研究成果为高瓦斯低渗透率厚煤层工作面预抽钻孔设计提供了参考依据。

Study on parameter optimization of gas extraction borehole layout scheme- Take Baode Coal Mine as an example

Abstract:Aiming at the problems such as low preextraction concentration, large attenuation coefficient and long gas preextraction time, the No.8 coal seam of Baode Coal Mine is taken as the research object. Through the experimental analysis and field test of permeability anisotropy of No. 8 coal seam, the optimal parameters of borehole layout and sealing process of No. 8 coal seam are studied. It is concluded that the best drilling and extraction effect is obtained when the pre-pumping borehole is 90° with the coal wall fracture and the drilling Angle is -6°. Using new material + bag as the sealing material, when the sealing distance is 8~16m, increasing the pressure and "two plug two injection" grouting method can effectively provide the sealing air tightness. Through three different test methods, it is determined that the effective extraction radius of the drilling hole is about 4m at 4 months and 4.5m at 6 months. Based on this, the optimal layout parameters of gas extraction borehole in the working face are obtained, which provides a reference for the design of pre-extraction borehole in the working face of thick coal seam with high gas and low permeability.