掏穴扩孔技术在低透气性松软煤层中的应用

Application of Hole Opening Technique in Soft Coal Seam with Low Permeability

余吾煤业主采的3号煤层,属于低透气性松软煤层,为提高穿层钻孔抽采效率,在N2203底抽巷穿层钻孔中进行掏穴扩孔技术试验。通过使用掏穴钻头对钻孔煤孔段扩孔,增加钻孔直径,增加煤壁暴露面积,增大周围煤体裂隙,使煤体得到充分卸压,提高了煤层的透气性,从而增强了钻孔瓦斯抽放效果。通过考察掏穴钻孔抽采效果,得出掏穴钻孔抽采流量优于普通钻孔,同时流量衰减时间多于普通钻孔,提高了钻孔抽采效率。

The No.3 coal seam,which is the main coal mine of the Yuwu coal industry,belongs to the low permeability soft coal seam.In order to improve the efficiency of drilling and drilling,the slotting easer hole expansion technique test was carried out in the drilling hole of the N2203 bottom pumping lane.By using the slotting drill to expand the hole,increase the diameter of the hole,increase the exposed area of the coal wall,increase the crack of the surrounding coal body,so that the coal body is fully discharged,and the permeability of the coal seam is improved,thus enhancing the drilling gas extraction effect.It is concluded that the drilling flow rate is better than that of ordinary drilling,and the flow attenuation time is more than that of ordinary drilling,which improves the drilling extraction efficiency.