Research on Effective Radius of Hydraulization Pressure-cutting Combined Extraction in Deep High Gas and Strong Outburst Coal Seams

Deep coal seam mining is affected by factors such as high gas pressure, high gas content and others, resulting in high construction costs and low gas extraction efficiency of gas pre-extraction drilling. In order to improve the permeability of deep high gas and strong outburst coal seams and optimize the construction process of through layer drilling hole, a study is carried out on the effective radius of gas extraction of hydraulization pressure-cutting combined pressure relief and permeability enhancement technology. The research results show that under different hydraulization measures, the hydraulization pressure-cutting combined with pressure relief and permeability enhancement technology improves the extraction concentration by 1.47 times and 1.25 times respectively compared to single hydraulic fracturing and hydraulic cutting technologies, and the average extraction purity per hole is improved by 2.04 times and 1.32 times respectively; Under different hole arrangements with different extraction radii, the average extraction concentration of the hole with 3.5 m extraction radius reaches 48.85%, the average gas extraction purity per hole reaches 0.025 7 m³/min, and the average decrease of gas pressure reaches 88.3%. This not only saves construction cost but also achieves better gas extraction effect. This study has certain reference significance for the arragements of through layer drilling holes of hydraulization pressure relief and permeability enhancement measures in deep high gas and strong outburst coal seams.