Repairing and Enhancing Permeability Technology and Equipment of Gas Drainage Borehole

According to a serious reduction problem of gas drainage production caused by the gas drainage borehole stability lost and jammed occurred easily, a h ydraulic operation machined of the gas drainage borehole was researched and developmentm, a high pressure, varied flow and continuous borehole repair technical sy stem was formed with a 16 mm outer diameter continuous wrapped steel tube and based on a high pressure water jet as core. The high pressure water jet caused by th e hydraulic operation machine of the gas drainage borehole was applied to the hydraulic borehole flushing and jam removing and the hydraulic jet fracturing and perme ability improvement of the gas drainage borehole. Thus a double permeability goal of the pressure releasing and fracturing was reached, the production of the available gas drainage boreholes could be restored and new boreholes construction could be eliminated. The technology applied to Daping Mine of Zhengzhou Coal Industry Gro up showed that after the borehole repaired and the permeability improved, the pure volume of the gas drainage could be increased over 800%.