Research on drilling and expansion integrated permeability enhancement technology and drilling tools without pump for low permeability coal seam
In response to the problems of low construction efficiency,poor stability of excavation devices,and the need for high-pressure pumps in conventional mechanical excavation and hydraulic punching for permeability enhancement construction in low permeability coal seams,a technology of drilling and expansion integrated permeability enhancement was proposed.The supporting dual channel water delivery device,dual channel drill pipe,and hole making device have been developed and subjected to on-site industrial tests.The results showed that the technology can achieve simultaneous operation of pilot hole and mechanical excavation with one drilling under static pressure water conditions in coal mines,solving the problems of unstable blade opening and closing of conventional excavation device and the need for high-pressure pumps,and reducing the cost of the technology.The supporting dual channel water delivery device,dual channel drill pipe,and hole making device worked flexibly,stably and reliably.The single hole in the cave making section was directly expanded to 4.4 times the original conventional drilling hole diameter,significantly improving the gas drainage effect.The successful application of this technology provides technical support for the gas drainage drilling construction in low permeability coal seam in underground coal mines.
low permeability coal seamintegrated drilling and expansionpermeability enhancement technologygas extractiondrilling construction
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