深部低透煤层瓦斯抽采钻孔封孔方式研究

Study on sealing way of gas drainage borehole in deep low-permeability coal seam

针对深部低透煤层瓦斯抽采钻孔封孔质量差的问题,分析了我国煤矿瓦斯抽采主要封孔方式技术特点以及存在的问题,认为巷帮及钻孔周围煤体应力"三带"分布、贯通裂隙发育情况及合理封孔深度的研究不够透彻,注浆压力和时间不足,钻孔应力失稳流动通道闭合、塌孔、淤塞等情况无法有效防治,是造成瓦斯抽采封孔效果不理想的主要原因。提出了研究扰动影响下钻孔周围煤体贯通裂隙发育情况,合理封孔深度,提高"两堵一注"囊袋堵头强度、注浆压力和时间,实施二次封孔以及孔壁支护等方面的改进对策,对深部矿井提高瓦斯抽采效率和安全生产具有重要的理论和现实意义。

Aiming at the problem of poor sealing quality of gas drainage boreholes in deep low permeability coal seams,the technical characteristics and existing problems of main sealing methods for gas drainage were analyzed in coal mines in China.It was considered that the study on stress distribution in three zones,development of through cracks and reasonable sealing depth around roadways and boreholes was not thorough enough,and grouting pressure and time were insufficient,and the flow passage of borehole stress instability was closed.The main reason for the unsatisfactory sealing effect of gas drainage was that the situation of closure,collapse and silting can not be effectively prevented and cured.It was of great theoretical and practical significance to improve gas extraction efficiency and safe production in deep mines by studying the development of coal seam through cracks around boreholes under the influence of disturbance,reasonable sealing depth,increasing the strength,grouting pressure and time of "two plugs and one injection" bag plug,implementing secondary sealing and hole wall support.