大采高工作面坚硬顶板水力压裂技术

Hydraulic fracturing technology for hard roof of working face with large mining height

针对大采高一次采全高采煤工作面回采过程中,经常出现的机头三角区采空区坚硬顶板难垮问题。通过对上覆岩层结构及强度进行测试、分析,结合煤层顶板特性及压裂密度大小对压裂效果的影响,确定采用分段压裂式水力压裂技术方案;并在井下现场开展水力压裂控制坚硬难垮顶板试验。结果表明,采用水力压裂技术后,工作面端头采空区顶板能够及时垮落,悬顶面积大幅度降低,工作面端头采空区悬顶沿推进方向一般最大不超过9 m,沿工作面方向最大不超过6 m,降低幅度达到70%以上,在大部分情况下,顶板能够随采随垮及时垮落,效果良好。

This article focuses on the problem of difficulty in crossing the hard roof of the goaf in the triangular area of the machine head during the mining process of working face with large mining height with one mining full height.By testing and analyzing the structure and strength of the overlying strata,combined with the characteristics of the coal seam roof and the impact of fracturing density on the fracturing effect,the segmented hydraulic fracturing technology scheme is determined to be adopted,and the test on the hydraulic fracturing control of hard and difficult crossing roof is conducted on the underground site.The results show that after use of hydraulic fracturing technology,the roof of the goaf at the end of the working face can collapse timely,and the suspended roof area is significantly reduced.The maximum length of the suspended roof along the goaf at the end of the working face is generally not more than 9 m,and the maximum length along the direction of the working face is not more than 6 m,with a reduction of over 70%.In most cases,the roof can collapse timely with mining with good effect.