松软煤层壁式密封瓦斯抽采技术研究

Study on Wall Sealing Technology of Gas Extraction in Soft Seams

高瓦斯低透气性松软顺层瓦斯抽采过程中，由于钻孔极易发生缩径、塌孔等工程问题，钻孔周围漏风严重，钻孔服务时间短，瓦斯抽采难度大且周期较长等成为瓦斯抽采的主要技术难题。通过分析松软煤层瓦斯抽采存在的关键问题，应用多孔介质渗流力学、流体平衡等理论及钻孔护孔原理，提出了松软煤层的固液耦合壁式密封技术。现场研究表明，应用固液耦合壁式密封技术抽采松软煤层瓦斯有效地阻止了巷道风流的漏入，极大地提高了瓦斯抽采效率，使得单孔瓦斯抽采浓度达90％以上，与煤矿所使用的聚氨酯袋配合密封液封孔技术相比，单孔纯瓦斯流量提高2～3倍，且抽采过程浓度稳定，对松软煤层瓦斯的高效抽采及实现煤与瓦斯共采和煤层气绿色开发理念具有重要意义。

In the process of mining-coal bed gas extraction at high gassy soft seams with low gas permeability, the serious air leakage in boeholes and the coal body around it, the short service time to drilling, the more difficult and the longer cycle of gas extraction become the main technical problems. By analyzing the key problems of soft coal seam gas extraction and application of the theory of porous media seepage mechanics, fluid balance and borehole protection principle, the solid -liquid coupling wall sealing technology in soft coal seam is put forward. The studies show that the solid-liquid coupling wall sealing technology can effectively prevent the tunnel wind leakaging into the drill hole and greatly improve the gas extraction efficiency. It makes the gas extraction concentration above 90% in the single drill hole, as well as the single pure gas content increase 2 - 3 times compared with sealing hole technology of hag with polyurethane jointed the sealing liquid in the coal mine and concentration is stable in the extraction process. The technology has great significance to the efficient gas extraction in soft coal seam and achieves the aim of mining coal and gas at the same time.