Theoretical Analysis and Practical Study on Reasonable Water Pressure of Hydro-fracturing Technology

Hydro-fracturing technology is a depressurization antireflection elimination outburst technology for low permeability outburst coal seam with high methane.At present,the depressurization antireflection elimination outburst mechanism is sufficiently mastered,and its application effectiveness in field engineering is also good,but how to determine hydro-fracturing parameters is not systematically described.Based on the hydro-fracturing mechanism and technics,the hydro-fracturing parameters and affecting factors are systematically analyzed,such as the water pressure,flux,water injection time,water injection velocity,borehole space,and borehole-sealed length.By field engineering test applied in the low permeability outburst coal seam with high methane,the reasonable hydro-fracturing parameters of FD003 working face in Yi'An coal mine were obtained.Effectiveness tests show that the drainage quantity and drainage concentration increase greatly,and the effectiveness of depressurization antireflection elimination outburst is also achieved as well as the one of wetting coal and dust suppression.