| The key problem, which influences the concentration of the gas extraction is the hole sealing quality of drilling holes. Whether extracting gas from the coal seam, adjacent coal seam or the worked out section, the high concentration of gas is vast extracted and the extraction effect is improved, if the quality of hole sealing is very well and orifice is not air leakage.Drilling field of water sealing is a new type of gas pre-drainage technology, which is based on the properties of methane is poorly soluble in water, using water to separate the gas in extraction tunnel from that in ventilation tunnel without sealing the drilling to avoid leakage into air, thus ensuring the sealing is good and high concentration of gas will be pumped out.The method that using drilling field of water sealing to extract high concentration of gas is studied by the numerical simulation, theoretical analysis and field industrial test. By using numerical analysis theory, constructing mathematics model, working out numerical simulation program, and finding out the flow law of gas drilling field of water sealing. An experiment of extraction gas by water sealing of drilling field of is studied, and the test site is in north third late area NO.68305of Du Erping mine in XISHAN coal electricity group co., LTD, which is the member of SHANXI coking coal group co., LTD.. A reasonable construction technology and technical proposal of water sealing in drilling field was putted forward, the test result:the concentration of gas was higher than60%by the technology of water sealing, during the stable gas extraction. And the highest concentration was up to85%.The factors influenced gas extraction, such as drilling arrangement, extraction negative pressure, geological structure, is also researched. |
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