低透气性薄煤层下向穿层钻孔立井集中排水技术及应用

    Centralized Drainage Technology and Application of Vertical Shaft in Low Permeability Thin Coal Seam Downward Drilling

    • 摘要: 针对下向穿层钻孔积水大时的排水难题,在分析压风排水原理的基础上,改变以往只以钻孔排水排渣的方式,探索出将钻孔内的积水引入到立井内再一次性集中排出的思路,创新提出了大孔径立井集中排水技术,阐述了立井集中排水原理和工艺,确定了立井最小排水压力。在1161(1)运输巷顶板巷试验单元试验并考察,结果表明:大孔径立井集中排水15 d后,下向钻孔内水位下降到了煤层底板以下,瓦斯抽采通道畅通,低透性薄煤层试验单元平均瓦斯抽采浓度提高到17.6%,平均百孔抽采纯量达到了0.13 m3/min,高效抽采时间持续了70 d以上,单元评价时间缩短了3.2倍。

       

      Abstract: Aiming at the difficult problem of centralized drainage of downward cross-layer boreholes, based on the analysis of the principle of pressure air drainage, the idea of introducing the accumulated water in boreholes into the vertical well and then centralized drainage once again is explored. The centralized drainage technology of large-borehole vertical wells is innovatively proposed, the principle and technology of centralized drainage of vertical wells are expounded, and the minimum drainage pressure of vertical wells is determined. The experimental investigation of 1161(1) roof roadway test unit shows that after 15 days of centralized drainage of large-diameter vertical shaft, the water level in downward boreholes drops below the coal seam floor, the gas extraction channel is open, the average gas extraction concentration of low permeability thin seam test unit is increased to 17.6%, the average 100 holes extraction purity is 0.13 m3/min, and the high-efficiency extraction time lasts for more than 70 days, and the unit evaluation is carried out. The time was shortened by 3.2 times.

       

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