Research on Efficient Extraction Technology of Three Soft and Low Breathable Coalbed Gas
Soft and low-permeability coal seams are difficult to control due to their poor permeability,difficulty in drilling holes,and rapid decline in extraction.Increasing the permeability of coal seams is the key to achieving efficient gas control.Therefore,hydraulic punching technology is applied to gas control in the 5205 fully mechanized mining face,and the sealing quality is improved by improving the drilling and sealing process to avoid gas leakage.After the completion of hydraulic punching in the 5205 bottom extraction roadway,the gas extraction concentration and extraction purity increased significantly,with an average of 32%～51%and 0.014～0.035 m3/min,respectively.Compared with other unperforated boreholes in the same area,the gas extraction concentration and purity increased by about 2.13～3.4 times and 20～125.7 times,respectively.The permeability coefficient of coal seams also increased from 0.004 m2/(MPa2·d)to 0.276 m2/(MPa2·d),an increase of approximately 62.73 times.The gas extraction technology adopted in the 5205 fully mechanized mining face has achieved significant results,which can significantly shorten the gas treatment time of the mining face.
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