Research on hydraulic permeability enhancement technology of high, medium and low pressure coal seam with deep well and high ground stress

Abstract

Aiming at the problem of poor gas extraction, long outburst time and low pre-drainage efficiency in the drilling zone of the floor tunnel through the drilling, the problem of mining excavation replacement is severely restricted. Dingji Coal Mine has carried out ultra-high pressure, medium pressure, and low pressure hydraulic cutting coal seam enhanced permeability gas extraction technology tests. Through continuous exploration and summary, it has achieved remarkable results, maximized extraction, and accumulated rich hydraulic coal Through experience. The results show that: the high-pressure hydraulic coal seam anti-reflection pre-draining unit has a maximum extraction pure volume of 3.1m3/min, the single-hole average extraction pure volume is 0.008m3/min; the medium-pressure hydraulic coal seam anti-reflection pre-extraction unit has a maximum extraction pure volume of 2.2 m3/min, single-hole average extraction pure volume is 0.005m3/min; low-pressure hydraulic coal seam permeability enhancement unit extraction pure volume is maximum 1.3m3/min, single-hole average extraction pure volume is 0.002m3/min. 1351(1)Yunshun’s gas pre-drainage rate reached 65.2% after adopting high-pressure hydraulic coal seam penetration enhancement measures. Through statistical analysis of the anti-burst prediction index during coal tunnel footage, the sensitive index is relatively small, and the effect of pre-draining outburst is better. The lane enters 200m per month. The permeability enhancement technology of hydraulic coal seam has a significant effect on the pre-drainage of gas in high ground pressure outburst coal seam. It provides an effective method for improving the gas pre-drainage and outburst work, which is worthy of in-depth promotion and application.