综放工作面顶板水力压裂卸压技术应用

Application of roof hydraulic fracturing pressure relief technology in fully mechanized caving face

针对煤矿回采工作面煤层开采后大面积坚硬顶板悬露在采空区内,致使回采工作面顶板垮落步距较大、来压剧烈、易引起支架压死等一系列安全问题,以雅店煤矿1403综放工作面为研究背景,通过对水力压裂技术与工艺流程进行分析,研究了水力压裂卸压技术的可行性,同时对水力压裂钻孔参数进行设计并开展现场水力压裂卸压试验,最后对压裂效果进行了分析。结果表明,压裂过程中存在明显的起裂阶段,随后在相对恒定压力的作用下,裂缝向深部扩展,压裂曲线呈现紧密的锯齿状;水力压裂可以有效弱化坚硬顶板、破坏其完整性,削弱顶板的强度和整体性,一定程度上能够改善支架的受力状况,达到减小或消除坚硬顶板对工作面回采危害的目的。

Due to the hard roof of coal seam,large area of hanging roof is easy to appear in goaf of working face,which leads to a series of safety problems such as large roof caving step distance,severe weighting behavior and easy to cause support damage.Taking No.1403 fully mechanized caving face in Yadian coal mine as the research background,through the adaptability analysis of hydraulic fracturing technology,the feasibility of hydraulic fracturing pressure relief technology in the working face is studied.At the same time,the drilling parameters of hydraulic fracturing are designed and field test is carried out,and the fracturing effect is evaluated.The results show that there is an obvious fracture initiation stage in the process of hydraulic fracturing,and then under the effect of relatively constant pressure,the fracture extends to the deep,and the fracturing curve presents a tight serrated shape.Hydraulic fracturing can effectively weaken the hard roof,destroy its integrity,weaken the strength and integrity of the roof,and improve the stress condition of the support to a certain extent,so as to reduce or eliminate the harm of the hard roof to the working face.