穿层钻孔煤层段变孔径掏穴卸压增透强化抽采瓦斯技术研究

 摘要：为提高预抽煤层瓦斯消突效果，本文提出了一种变孔径的钻孔卸压增透技术，并在下山揭煤钻孔中进行了试验研究。通过对已施工好的下向穿层钻孔实施陶穴扩孔后，实际钻进出煤量相应增加，钻孔的卸压影响范围增大，钻孔周围的煤体变形和透气性增大，抽采瓦斯效果显著提高。掏穴钻孔与考察钻孔抽采瓦斯情况相比，具有显示流量抽采时间长、抽采浓度高和抽采瓦斯量大的特点。穿层钻孔煤层段变孔径掏穴扩孔卸压增透强化抽采瓦斯技术具有易操作简单、成本低和提高抽采效果显著等优点，值得在低透气性高瓦斯突出煤层消突实践中推广应用，为高突煤层预抽消突提供了一种行之有效的方法。

Research on Gas Drainage of Stress Relief and Permeability Improvement by Variable Borehole Diameter

Abstract: In order to improve effect of gas drainage, the paper presents a technique of stress relief and permeability improvement by variable borehole diameter. The experiment is implemented during downward coal uncovering. The mass of coal output is increased during drilling after boreholes reaming, which induces range expanse of stress relief, permeability improvement and significant enhancement of gas drainage. By contrast with normal boreholes, the reaming ones demonstrate longer time, higher concentration and larger flow capacity of gas drainage. The advantages of the technique are operation simplicity, low cost and significant effect. Thus it is an effective method and worth popularizing in outburst elimination of low permeability and high gas outburst coal seams.