水力压裂-水力割缝联合增透技术应用

Application of permeability improving technology combined with hydraulic pressure fracturing and hydraulic slotting

针对重庆松藻逢春煤矿高构造应力区域煤层透气性差、钻孔垮孔严重、瓦斯抽采浓度低等问题,在预抽煤层瓦斯时采用水力压裂-水力割缝联合增透技术,分析了该技术的增透原理,并在张狮坝采区＋680N11203回风巷-2区钻场进行了对比试验。结果表明：水力压裂-水力割缝联合增透技术与水力压裂技术、水力割缝技术和普通钻孔抽采技术相比,明显增加煤层的透气性,提高瓦斯抽采浓度和抽采效果;初次抽采瓦斯体积分数为28%-62%,较其他3种方案依次提高了8%-13%、12%-20%和18%-36%;汇总瓦斯体积分数为36%,依次是其他3种方案的1.33、1.8、5.1倍;水力压裂-水力割缝联合增透技术能保持长时间的高效抽采时间,抽采28天后,其瓦斯累积抽采量为7 908m^3,分别是其他3种方案的1.5、1.7、7倍,且该钻场汇总浓度基本无衰减趋势,仍保持在36%左右。

Abstract： According to the poor seam permeability, serious borehole collapsing,low concentration of the gas drainage and problems of the high tectonic stress area in Fengchun Mine of Chongqing Songzao Company, during the gas pre-drainage period, the permeability improving technology combined with hydraulic pressure fracturing and hydraulic slotting was applied, the permeability improving principle of the hy- draulic pressure fracturing and hydraulic slotting technology was analyzed and the comparison tests of the technology were conducted in No.-2 Block drilling site of the air returning gateway in No. ＋680N11203 coal mining face of Zhangshiba Mining Block.The results showed that in comparison with the hydraulic pressure fracturing technology, hydraulic slotting technology and conventional borehole gas drainage technology, the permeability improving technology combined with the hydraulic pressure fracturing and hydraulic slotting could obviously improve the permeability of the seam and improve the gas drainage concentration and the gas drainage effect.The volume fraction of the first gas drainage was 28% - 62% and was 8%-13%, 12%-20% and 18%-36% times higher than other three plans individually.The total volume fraction of the gas drainage was 36% and was 1.33,1.8 and 5.1 times higher than other three plans individually.The permeability improving technology combined with the hydraulic pressure fracturing and hydraulic slotting could keep a long time of the high efficient gas drainage.After 28 days of gas drainage operation, the accumulated volume of the gas drainage was 7 908 m3 and was 1.5,1.7 and 7 times higher than other three plans individually.The total concentration of the gas drainage in the drilling site was not in an attenuation tendency basically and could be kept at about 36%.