Research and Application of High Pressure Maintaining Water Injection Outburst Elimination Technology for Downward Through Layer Drilling Hole
Aiming at the existing safety issues of high ground stress coal and gas outburst coal seams,the construction of downward through layer high pressure maintaining water injection drilling hole is carried out in high extraction roadways.Through the implementation of the"two plugging and two injection"hole sealing process with pressure,when the effective hole sealing length is 17 m,can withstand pressure of at least 48 MPa,which improves the hole sealing strength;Adopting multiple repetitions of high pressure maintaining water injection construction process to enhance water injection volume and water injection effect,implementing interception and pressure relief process,balancing and weakening high concentrated stress in coal seams,and controlling the influence range of high pressure water injection;The high pressure maintaining water injection pressure is 30-47 MPa,with 2-5 times of water injection.The maximum water injection volume for a single hole reaches 159 m³,the maximum effective influence radius of high pressure maintaining water injection is 101 m,and the engineering quantity of gas pre extraction drilling hole is reduced by 55.9%.The gas governance cycle is reduced by 15 months,improving the efficiency and effect of gas governance.Through experiments,the permeability of coal seams is increased,the gas extraction effect is improved,and the outburst danger of coal seams is eliminated.
high pressure maintaining water injectioninterception and pressure relief process"two plugging and two injection"hole sealing process with pressure
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