超高压水力割缝卸压抽采区域防突技术应用研究

Application research on regional outburst prevention technology of ultra-high pressure hydraulic slot pressure in relief drainage area

为了有效解决丁集矿高地应力、低透气性突出煤层煤巷条带瓦斯区域预抽效率低、预抽达标后区域验证指标仍超标的问题,在该矿1351(1)运输巷煤巷条带穿层预抽钻孔进行了超高压水力割缝卸压增透技术应用研究,利用水力割缝卸压增透原理确定了超高压水力割缝设备组成,选型配套了超高压清水泵、超高压软管、超高压旋转水尾、水力割缝钻杆、高低压转换割缝器、钻头和超高压远程操作台等超高压水力割缝设备,考察了相同孔径未割缝钻孔、割缝钻孔瓦斯涌出量及割缝钻孔瓦斯抽采量,理论研究了百米煤孔初始瓦斯涌出量、瓦斯涌出衰减系数及不同预抽时间、预抽率条件下的有效抽采半径,现场检验了顺层钻孔预抽措施单元、穿层钻孔水力冲孔措施单元、穿层钻孔水力割缝措施单元的预抽瓦斯区域防突措施效果,统计了不同措施预抽单元局部补充措施执行情况、局部措施效果,分析评价了超高压水力割缝卸压增透效果。结果表明:针对丁集矿11-2煤层工程条件选型配套的超高压水力割缝设备参数是合理的,在1351(1)运输巷煤巷对11-2煤层条带进行穿层钻孔超高压水力割缝措施卸压增透效果显著,与未增透措施相比,煤层透气性系数提高了25.9倍、113 mm孔径的穿层钻孔百米煤孔初始瓦斯涌出量提高了5.5倍、瓦斯涌出衰减系数降低了73.4%、预抽15 d和30 d达35%预抽率的钻孔间距提高了84.3%和53.0%,与穿层钻孔水力冲孔相比,煤巷条带防突局部补充措施工程量降低了50.0%、煤巷平均掘进速度增加了1倍。

In order to effectively solve the problem of low pre-draining efficiency of the gas area of the coal roadway in Dingji Coal Mine with high ground stress and low permeability,the regional verification index still exceeds the standard after the pre-drainage meets the standard.Drilling holes were used to study the application of pressure relief and anti-reflection technology for ultra-high pressure hydraulic slits.The principle of pressure relief and anti-reflection enhancement of hydraulic slotting and the composition of ultra-high pressure hydraulic slotting equipment were summarized.Ultra-high pressure water-cleaning pumps,ultra-high pressure hoses,ultra-high pressure rotary tail,hydraulic slotting drill pipe,high and low pressure switching slotting device,drill bit and ultra-high pressure remote operation table and other ultra-high pressure hydraulic slotting equipment were selected and matched,the natural gas emission from uncut drilling and slotted drilling with the same borehole diameter and gas extraction from slotted drilling were investigated.The initial gas emission and gas emission attenuation coefficient,and the effective extraction radius under different conditions of pre-drainage time and pre-drainage rate conditions were studied theoretically.The effect of gas outburst prevention measures in the pre-drainage of gas unit of the bedding layer and hydraulic slotting by drilling through the seam were tested on site,the implementation of partial supplementary measures and effect of partial measures of pre-extraction unit with different measures were counted.The situation and the effects of local measures were analyzed and evaluated for the effect of pressure relief and permeability enhancement of ultra-high pressure hydraulic slits.The results show that the parameters of ultra-high pressure hydraulic slotting equipment matched the type selection of No.11-2 coal seam engineering conditions in Dingji Coal Mine were reasonable,the effect of pressure relief and permeability enhancement by ultra-high pressure hydraulic slotting in cross-layer boreholes of No.11-2 coal seam in 1351(1)coal roadway along transport channel was remarkable.Compared with the non-permeability-increasing measures,the permeability coefficient of the coal seam was increased by 25.9 times,the amount of gas emission from a hundred meter coal hole through a 113 mm hole increased by 5.5 times,the gas emission attenuation coefficient was decreased by 73.4%,and the distance between boreholes with 35%pre-drainage rate after 15 and 30 days of pre-drainage were increased by 84.3%and 53.0%.Compared with the hydraulic punching of the through-hole drilling,the local supplementary measures of coal roadway strips after ultra-high pressure hydraulic cutting was reduced by 50.0%,and the average driving speed of coal roadway was doubled.