深部厚硬岩层压裂控制冲击弱化机理及可压裂性评价

Mining pressure weakening mechanism by ground fracturing and fracturing evaluation of hard rock strata

为了探究深部厚硬岩层对冲击地压的影响以及分析岩层的可压裂性,提出了采用地面水平井压裂技术对采场上覆厚硬岩层进行压裂控制,通过改变厚硬岩层的破断特征,达到降低厚硬岩层的破断步距和能量释放强度,并通过试验分析,得到上覆厚硬岩层的脆性系数、脆性矿物含量、黏土矿物含量、成岩作用等参数,综合定量评价厚硬岩层的可压裂性大小。研究结果表明:在厚硬岩层中产生的水平或垂直裂缝面,均有助于减弱厚硬岩层破断失稳引起的下伏回采空间的矿压显现;红庆河煤矿顶板主控岩层脆性系数为67%、黏土矿物含量为28.46%,脆性矿物含量为60.82%,镜质体反射率R;为0.52%,数据表明主控岩层具有较高的可压裂性,可为后续地面水平井压裂技术的实施提供参考。

To study the effect of hard rock strata on the impact ground pressure and its fracturing,the ground horizontal well fracturing technology is proposed to control the thick hard roof to reduce the breaking step distance and energy release strength by changing its breaking characteristics. Based on the experimental analysis,the parameters of rock layer brittleness,fragile and clay mineral content and rock formation are obtained to comprehensively evaluate the fracture evaluation of thick hard roof. The results show that the horizontal and vertical crack on the thick hard roof helps to weaken the mining pressure of the instability and breaking of the thick hard roof.The fragility coefficient of the main controlled rock layer on the roof of Hongqinghe Coal Mine was 67%,the clay mineral content 28.46%,the brittle mineral content of the main controlled rock layer 60.82%,and the mirror mass reflectivity Ro 0.52%. The data indicate that the master rock layer has a high fracturing ability. This study provides a reference for the subsequent implementation of ground horizontal well fracturing technology.