水力割缝封孔提高瓦斯抽采浓度试验研究

Experimental study on increasing gas drainage concentration by hydraulic slotting and hole sealing

为了解决顺层钻孔封孔漏气及瓦斯抽采浓度低问题,提出了割缝封孔提浓方法,开展了超高压水力割缝卸压增透、钻孔合理封孔深度及割缝位置研究,通过理论分析、数值模拟、钻孔排渣量考察,确定了封孔位置和割缝深度。在此基础上,开展了现场试验研究,考察了钻孔瓦斯抽采浓度、抽采瓦斯纯量等,结果表明:采用割缝带压封孔工艺,相较于传统“两堵一注”封孔方式,钻孔平均瓦斯抽采浓度提升1.77~2.14倍。在孔口割缝封孔工艺基础上,对煤层进行超高压水力割缝,钻孔平均抽采浓度70.7%,抽采纯量为割缝前钻孔的3.96倍。割缝封孔提浓作为一种新的提高瓦斯抽采效率的技术途径,具有借鉴意义。

In order to solve the problems of gas leakage and low gas extraction concentration in bedding hole sealing,the concentration method of slotted hole sealing was put forward,the research on ultra-high pressure hydraulic slotting pressure relief and permeability enhancement,reasonable hole sealing depth and slotting position were carried out,and the hole sealing position and slotting depth were determined through theoretical analysis,numerical simulation and investigation of borehole slag discharge.On this basis,the field test research was carried out to investigate the gas drainage concentration and net amount of gas in the borehole.The results show that compared with the traditional"two plugging and one injection"sealing method,the average gas drainage concentration in the borehole is increased by about 1.77~2.14.On the basis of the hole opening slotting and sealing technology,the coal seam is subject to ultra-high pressure hydraulic slotting,the average extraction concentration of boreholes is 70.7%,and the net amount of extraction is 3.96 times of that of the borehole before slotting.As a new technical way to improve gas drainage efficiency,slotting,hole sealing and hole concentration has reference significance.