本煤层双套管高效瓦斯抽采技术及应用
Application of High Efficient Gas Drainage Technology with Double Casing Pipe to Mining Seam
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摘要: 为了解决本煤层抽采钻孔抽采瓦斯流量小、浓度低、易塌孔、封孔难的技术难题,分析了现有抽采技术的不足,根据平煤股份八矿己15-13330工作面运输巷的实际情况,提出采用本煤层双套管高效瓦斯抽采技术,并对双套管抽采的作用原理、双套管的合理长度等进行了研究。现场应用结果表明:在煤体普氏系数f≥0.25的本煤层钻孔瓦斯抽采中,采用双套管高效瓦斯抽采技术,可有效防止钻孔塌孔堵塞,提高钻孔密封质量,单孔瓦斯抽采平均初始体积分数达到89%,瓦斯纯流量提高了80%,抽采31d后瓦斯抽采流量仅衰减12%;试验工作面抽采干管瓦斯体积分数维持在18%以上,工作面煤层瓦斯预抽率达到45%。Abstract: In order to solve the technical difficult problems of the low drainage gas flow, low gas content, easy borehole collapsing and difficult borehole sealing in t he gas drainage borehole of the mining seam, the paper analyzed the shortages of the available gas drainage technology.According to the actual condition of the transp ortation gateway in F15- 13330 coal mining face of No.8 Mine of Pingdingshan TianDan Coal Company Ltd., a high efficient gas drainage technology with double casing pipe was provided in the mining seam.The paper studied on the function principle of the gas drainage with the double casing pipe and the rational length of the double C asing pipe and others.The site application results showed that in the borehole gas drainage in the mining seam with the seam Protodyakonov coefficient f20.25, the hig h efficient gas drainage technology with the double casing pipe applied could effectively prevent the borehole collapsing and jammed and improve the sealing quality of the borehole.The average initial volume fraction of the gas drainage with sigle borehole was up to 89%, the pure gas flow value was improved by 80% and the gas drain age flow value only reduced by 12% after drainaged 31 days. The gas volume fraction of drainage pipe in test face kept over 18%, the gas drainage rate in coal seam of the mining face reached to 45%.