观音山煤矿一井石门揭煤防突技术研究

Research on outburst prevention technology about rock cross-cut coal uncovering in Guanyinshan Coal Mine

针对低透气性煤层石门揭煤防突使用常规预抽方法存在钻孔多、效果差和周期长的问题,提出采用水力压裂石门揭煤技术,通过增加煤层裂隙提高透气性、提升抽采效果,从而缩短揭煤周期。同时将水力压裂石门揭煤技术在观音山煤矿一井与常规密集钻孔预抽技术进行对比试验,试验结果表明:压裂后的平均瓦斯抽采浓度由压裂前的20%提高到45%,提高了2.25倍;单孔抽采纯量平均由2×10^(-3)m^3/min提高到5×10^(-3)m^3/min,提高了2.5倍;煤层瓦斯含量由11.238 6 m^3/t降低到4.414 0~6.785 2 m^3/t,降低了39.6%~60.7%;预抽时间由9个月缩短到5个月,缩短44%。

In view of the matter of too many drilling holes,poor effects and the long period when using conventional drainage methods during rock cross-cut coal uncovering in low permeability coal seam,hydraulic fracturing technology was presented to increase the fracture of coal seam,improve the permeability and gas extraction effect,so as to short the period of coal uncovering. The comparative experimental study of hydraulic fracturing rock cross-cut coal uncovering technology and conventional intensive drilling drainage technology that was been done in Guanyinshan Coal Mine,and the result shows that,comparing with the previous technology without fracture,the gas extraction concentration of fracturing increased from 20% to 45%,improved 2. 25 times than that before. A single borehole extraction of gas quantity increased from 2 × 10^-3m^3/ min to 5 × 10^-3m^3/ min,improved 2. 5 times than before. The coal seam gas-bearing capacity reduced from 11. 238 6 m^3/ t to 4. 414 0 - 6. 785 2 m^3/ t,which got down at a range from 39. 6% to 60. 7%. Besides,the time of pre-drainage can be shortened from 9 months to 5 months,reduced nearly 44% of the time.