Application of hydraulic reaming technology of No.3 coal seam floor layer-crossing borehole in Sangshuping No.2 Mine
The 3# coal seam of deep fourth mining area of Sangshuping No.2 Mine is of high gas content,high gas pressure,high geo-stress,poor permeability,soft coal,and serious outburst hazard.It is urgent to solve the technical issues of difficult layer-crossing drilling gas extraction of coal seam with low efficiency.Through comparative experiments on the drilling-enlar-ging integrated technology for pressure relief permeability-enhancing with high pressure water jet,we find that when the dis-charged coal debris was 0.75％and 2.35％,respectively,the borehole diameter is enlarged 3 times and 8 times,hectometer borehole gas flow is increased 1.3 times and 3 times,gas concentration boosted 1.5 times and 1.8 times,and extraction effi-ciency improved more than 28％.After discharging mass coal debris,the exposed area and pressure-relief range of coal seam are enlarged,and the extraction is significantly improved with obviously better effect to relieve the strained relations of wi-ning-driving-extraction and achieve high efficiency extraction of mine gas.
gas extractionhydraulic reaminglayer-crossing boreholehigh-pressure water jetpressure relief permeability enhancing
万方数据
维普
