摘要
为了提高冲击地压矿井防冲工程的卸压效果与效率,针对现有防冲手段无法对工作面进行大面积超前区域治理的现状,提出利用定向长钻孔分段水力压裂技术对工作面坚硬顶板进行超前区域弱化的治理思路。运用能量理论分析了分段水力压裂的卸压原理及防冲可行性,建立了水力压裂层位判识方法。利用判识方法确定了工作面上方覆岩硬层位置,覆岩中能量积聚的重点层位及能量释放的集中层位。通过建立多物理场数值计算模型探究了水力压裂形成的孔隙水压力场与钻孔距离的关系,最终确定了压裂钻孔布置层位为煤层顶板以上33 m及73 m,同一层位钻孔间距为75 m。基于上述结果在现场开展了工程应用,并采用煤体应力监测与微震监测对防冲效果进行了验证。结果表明,经过定向长钻孔分段水力压裂后与其他工作面相同区域相比,浅孔应力波动降低65.7%,深孔煤体应力波动降低69.6%;微震事件在空间中的发育范围超前工作面距离减少28.0%,侧向发育距离减少34.9%,最大发育高度减少42.4%;微震事件总能量、事件频次及单刀能量分别降低73%、66%及72%,验证了定向长钻孔分段水力压裂技术在冲击地压防治领域中应用效果显著。
In order to improve the pressure relief effect and efficiency of rock burst prevention and control engineering in rock burst mine,and in view of the current situation that the existing means are unable to control the large area leading area of the working face,this paper puts forward the treatment idea of weakening the leading area of the hard roof by using directional long borehole sectional hydraulic fracturing technology.The pressure relief principle and rock burst control feasibility of sectional hydraulic fracturing technology are analyzed by using energy theory,and the layer identification method of hydraulic fracturing is established.By using the identification method,the location of the hard layer,the key strata with energy accumulation and the concentrated strata of energy release in the overlying rock above the working face are determined.Through the establishment of a multi-physical field numerical calculation model,this paper explores the relationship between the pore water pressure field formed by hydraulic fracturing and the drilling distance,and finally determines that the layers of fracturing boreholes are located at 33 m and 73 m above the roof,and the distance between boreholes in the same layer is 75 m.On the basis of the above results,the engineering application is carried out in the field and the rock burst prevention effect is verified by coal stress monitoring and microseismic monitoring.The results show that after the application of sectional hydraulic fracturing with directional long boreholes,compared with the same area of other working faces,the stress fluctuation in shallow holes is reduced by 65.7%,and that of coal body in deep holes is reduced by 69.6%.The leading distance of the development range of microseismic events in space ahead of the working face is reduced by 28.0%,the lateral development distance is reduced by 34.9%,and the maximum development height is reduced by 42.4%.The total energy,event frequency and single knife energy of microseismic events are reduced by 73%,66%and
作者
王泽阳
郑凯歌
王豪杰
刘昌益
WANG Zeyang;ZHENG Kaige;WANG Haojie;LIU Changyi(CCTEG Xi'an Research Institute Co.,Ltd.,Xi'an,Shaanxi 710054,China)
出处
《中国煤炭》
2022年第7期68-78,共11页
China Coal
基金
“十三五”重大专项(2016ZX05045002-002)。
关键词
冲击地压
动力灾害
能量理论
区域治理
分段水力压裂
定向长钻孔
rock burst
dynamic disasters
energy theory
regional control
sectional hydraulic fracturing
directional long borehole
