Research on integrated technology of"pumping-injection"drainage and slag discharge in downward low concentration drilling
In order to prevent the occurrence of coal and gas protrusion accidents in Chensilou Coal Mine in Yongxia mining area,after using hydraulic slag discharge drilling to extract gas,it was found that there was a large amount of water and coal slag inside the drill-ing,which blocked the pore channels inside the coal body,affecting the gas transport output of the coal seam and the stability of the drilling wall,seriously affecting the gas extraction effect.In response to the urgent need to solve the problem of drainage and slag dis-charge of the down hole in the coal mine,we proposed to use the pressure air blowing hole technique to bring water and coal slag out of the hole and clear the blocked channels of the drilling.Water and coal slag inside the hole were carried out outside the hole.The tech-nique was applied well in the underground site of Chensilou Coal Mine.The average concentration in the drilling after blowing increased from 11.86％to 18.73％～56.38％,and the low concentration drilling was enhanced significantly,instead of the previous hydraulic slag discharge drilling technique,it achieved the purpose of efficient gas extraction and ensuring the safe production of coal mines,and it had certain guiding significance for the timely elimination of water and coal slag in the process of gas extraction from drilling.On this basis,a set of integrated technology and techniques of"pumping-injection"drainage and slag discharge in downward low concentration drilling has been developed,which is of great significance for the drainage and slag discharge of downward low concentration drilling.
low concentration drillingdrainage and slag dischargepressure air blowing holegas extractiondrilling blockage
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