“变径扩孔”工艺提高煤层瓦斯抽采效率技术研究

Research on "Variable Diameter Expansion" Technology to Improve Coal Seam GasDrainage Efficiency

针对含瓦斯煤层小倾角钻孔中,水泥封孔浆液凝固收缩,易在封孔段、钻孔壁之间形成"月牙"形漏气通道,从而导致瓦斯抽采失效等问题。通过使用"变径扩孔"工艺形成台阶式抽采孔,采用囊袋"两堵一注"方法进行封孔,并考虑不同负压对抽采浓度的影响,在实验室进行了物理实验研究。

Aiming at the problems of small-inclined boreholes in gas-bearing coal seams,the cement sealing slurry solidifies and shrinks,and it is easy to form a crescent-shaped air leakage channel between the sealing section and the borehole wall,resulting in the failure of gas drainage.A stepped extraction hole was formed by using the"reducing hole expansion"process,and the hole was sealed with a"two plugs and one injection"method of bagging.Considering the effect of different negative pressures on the extraction concentration,physical experiments were conducted in the laboratory.