基于坚硬煤层条件的顺层钻孔增透技术研究

Research on bedding drilling and permeability increasing technology based on the condition of hard coal seam

为了解决低透气性坚硬煤层顺层钻孔抽采影响范围小、抽采效果差等问题,分析了坚硬煤层高压水射流破坏过程,采用数值模拟的方法研究了超高压水射流环形割缝卸压增透机制,研制了新型超高压水力割缝成套装置,并现场考察了坚硬煤层煤巷条带顺层钻孔超高压水力割缝应用效果。结果表明:采用超高压水力割缝后,坚硬煤层透气性提升约20倍,钻孔平均抽采瓦斯纯量提高2.0~2.5倍,抽采达标时间缩短67%以上,月掘进速度提高约50%,掘进期间无瓦斯异常现象,实现了坚硬煤层煤巷条带安全、快速掘进。

In order to solve the problems such as the influence scope of extraction is small and the extraction effect is poor on bedding drilling in low-permeability hard coal seam,the high pressure water jet failure process of the hard coal seam was analyzed,and the numerical simulation method was used to study the mechanism of pressure relived and permeability enhanced of ultra-high pressure hydraulic slotting,a new set of ultra-high pressure hydraulic slotting device was developed.In addition,the application effect of borehole drilling and ultra-high pressure hydraulic slotting along the strip of coal roadway in hard coal seam was investigated on site.The results show that after the use of ultra-high pressure hydraulic slotting,the permeability of hard coal seam is increased by about 20 times,the average gas extraction volume of borehole is increased by 2.0 to 2.5 times,the time required to reach the standard is reduced by more than 67%,and the monthly driving speed is increased by about 50%.During tunneling,there is no abnormal gas phenomenon,and the tunneling in hard seam coal roadway strip is safe and fast.