水力化卸压增透技术在石门快速揭煤中的应用研究

Research on the application of hydraulic pressure relived and permeability enhanced technology in cross-cut rapid uncovering coal

为了解决西南地区松软煤层所面临的瓦斯抽采难度大、消突时间长的难题,在新维煤矿石门揭穿8^#突出煤层期间,通过抽采钻孔,采用单孔多次高压水力割缝形成缝槽,并同时实施中压注水实现导向性水力压裂的煤层增透方法,增加了待揭露区域煤层的透气性,缩短了预抽时间。结果表明:高压水力割缝形成缝槽为水力压裂起到一定的导向作用,水力压裂裂缝和割缝缝槽共同形成连贯塑性区;经过水力化措施后,煤层透气性提高,单孔抽采瓦斯流量平均提高2倍;单孔抽采瓦斯浓度平均提高3倍左右,实现了石门快速揭煤。

In order to solve the problem of gas drainage difficulty and long outburst elimination time in soft coal seams in Southwest China,during the period of 8^#outburst coal seam exposed by cross-cut in Xinwei Coal Mine,the seam slot was formed by multiple high pressure hydraulic slotting with a single borehole,at the same time,medium pressure water injection was applied to realize the permeability enhanced of directional hydraulic fracturing of coal seam,the permeability of coal seam to be exposed was increased,and the pre-extraction time was shortened.The results show that the seam slot formed by high pressure hydraulic slotting plays a certain guiding role for hydraulic fracturing,a coherent plastic zone is formed by hydraulic fracturing fracture and seam slotting;after the hydraulic measures,the permeability of coal seam is improved,the gas drainage flow of single hole is increased by 2 times on average;the average drainage concentration of single borehole is increased about 3 times on average,cross-cut rapid uncovering coal is realized.