高瓦斯煤层临近富水岩层瓦斯抽采优化技术研究

    Research on optimization technology for gas extraction in high-gas coal seams adjacent to water-rich rock layers

    • 摘要: 为解决贵州地区低透气性高瓦斯煤层瓦斯抽采效率低、封孔质量差,尤其富水地质条件下钻孔串漏、积水滞留等难题,支撑煤矿瓦斯灾害防治与资源化利用,以米箩煤矿110106工作面(埋深345 m、原始瓦斯含量10.91 m3/t)为工程背景,开展针对性瓦斯治理技术研究。通过构建“钻孔管控-裂隙充填-封孔优化-积水治理”协同技术体系:采用钻孔施工“五环节”过程管控保障钻孔到位精度,注浆充填裂隙解决串孔漏气问题;研发“三堵两注”封孔工艺与“洗净-精下-高压”一体化封孔技术,阻断水砂倒灌与瓦斯泄漏;配套积水排放管控措施消除积水对抽采的稀释影响。研究结果表明:该技术体系有效解决了含水层富水、高应力条件下瓦斯抽采的核心问题,19组试验钻孔中60个钻孔瓦斯抽采浓度超50%;110106运输巷23个循环区域验证显示,钻屑瓦斯解吸指标K1值均小于0.36,炮后瓦斯浓度较优化前下降0.2%~0.3%,实现钻孔“到位、封严、水放干”目标。研究提出的瓦斯与水害协同治理技术,可显著提升低透气性富水高瓦斯煤层的瓦斯抽采效率与防突安全性,为同类矿井瓦斯高效抽采及资源化利用提供可靠技术参考。

       

      Abstract: To address the issues of low gas extraction efficiency and poor sealing quality in low-permeability high-gas coal seams in Guizhou Region, especially the problems of drilling string leakage and water accumulation retention under water-rich geological conditions, and to support the prevention and utilization of coal mine gas disasters, a targeted gas control technology research is conducted based on the 110106 working face of Miluo Coal Mine(with a burial depth of 345 m and an original gas content of 10.91 m3/t). A collaborative technical system of “drilling control-fracture filling-sealing optimization - water drainage” is constructed: the “five-step” process control during drilling construction is adopted to ensure the accuracy of drilling position, and grouting filling of fractures is used to solve the problem of drilling string leakage; the “three-seal and two-injection” sealing technology and the “cleaning-precise lowering-high-pressure” integrated sealing technology are developed to block the backflow of water and sand and the leakage of gas; the drainage control measures for water accumulation are implemented to eliminate the dilution effect of water accumulation on gas extraction. The results show that this technical system effectively solved the core problems of gas extraction in water-rich and high-stress conditions, and the gas extraction concentration of 60 out of 19 test drilling holes exceeded 50%; the 23 circulation areas of the 110106 transportation alley are verified, and the K1 value of drill cuttings gas desorption indicators in all 23 areas is less than 0.36, and the gas concentration after blasting is reduced by 0.2%-0.3% compared to the optimized before, achieving the goal of “in-place, sealed, and water drained dry” for the drilling holes. The gas and water disaster collaborative control technology proposed in this study can significantly improve the gas extraction efficiency and outburst safety of low-permeability water-rich high-gas coal seams, providing reliable technical references for the efficient gas extraction and resource utilization of similar mines.

       

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