小保当煤矿综采工作面水压预裂夹矸层技术应用

Application of hydraulic pre-cracking on dirt band of fully mechanized working face in Xiaobaodang Coal Mine

基于小保当煤矿大采高工作面厚硬夹矸层影响工作面的安全高效回采现状,采用水压预裂煤体硬夹矸层技术,结合工作面的夹矸3D结构及工作面巷道地质写实,确定了煤层夹矸预裂合理分区,制定了水压预裂夹矸层钻孔参数及布置方案,设计了夹矸预裂施工工艺。试验结果表明:在定向水力压裂过程中,压裂效果与预裂压力、预裂时间及注水量等参数有关,其中,当预裂钻孔夹矸起裂压力为26~29MPa、预裂时间120~190min、注水量13~20m^(3)时,夹矸裂隙发育效果分为压裂区、软化和裂隙二次扩展区域、裂隙扩展区。现场预裂效果检验表明,采用水压预裂夹矸层技术后工作面回采期间采煤机破岩效率明显提高,预裂效果明显。

As the safe and efficient mining of the high-cutting face in Xiaobaodang Coal Mine is hindered by the hard and thick dirt band, hydraulic pre-cracking is applied on the hard dirt band, combining with the gangue 3 D structure of the working face and the roadway geological realism, so that the coal seam dirt band pre-cracking sections are reasonably divided, and drilling layout and parameters scheme is formulated for the hydraulic pre-cracking, and the pre-cracking construction process is designed. The test results show that: in the directional hydraulic fracturing, the fracturing effect is related to parameters such as pre-cracking pressure, pre-cracking time and water injection volume. When the initiation pressure of the dirt band in the cracking hole is 26~29 MPa, and the pre-cracking time is 120~190 min, the water injection volume is 13~20 m^(3),the dirt band fracture development is divided into fracturing zone, softening and fracture secondary expansion zone, and fracture expansion zone. After adopting the hydraulic pre-cracking technology, rock breaking efficiency of the shearer is significantly improved, and the pre-cracking effect is obvious.