基于高密度电法温纳装置的三维电阻率反演应用

在金矿采空区钻孔定位时,较多地依据二维高密度电法剖面反演来计算采空区的位置及产状,由于金矿采空区产状变化复杂,二维反演仅反映了采空区沿纵断面的展布形态,因采空区影响范围内测点较少至使反演目标边界误差较大,盲目布设钻孔会造成探测成本的提高,为实现精确探查,精准反演采空区的边界范围、走向及倾向,提高钻孔准确率,降低勘察成本,在蓬莱大柳行金矿试验通过布设多条等距高密度电法剖面(剖面间距为50 m、点距20 m),构造了不均匀测网,利用高密度电法仪采集温纳排列测深数据,将该排列数据进行了对称四极测深数据格式转换.采用该测网建立了三维电阻率反演数据格式,进行了三维电阻率反演,经钻探验证采空区中心埋深与三维电阻率反演低阻体埋深误差3.1 m.最终反演迭代精度与二维高密度电法剖面反演精度相差9.5%,为准确布钻提供资料.

Application of 3-D resistivity inversion based on Winner device of high density electricity method

When locating boreholes in goaf of gold mine,the location and occurrence of goaf are calculated mos-tly by inversion of two-dimensional high density resistivity profile.Because the occurrence of goaf of gold mine varies complex,two dimensional inversion only reflects the distribution pattern of goaf along the longitudinal section,and the boundary error of inversion target is caused by fewer measuring points in the affected area of goaf.In order to achieve accurate exploration,prec-ise inversion of the boundaries,directions and ten-dencies of mined-out areas,increasedrilling accuracy and reduce explora-tion costs,several equidistant high-density resistivity profiles(50 m and 20 m spacing between sections)were laid out in the experiment of Daliuhang Gold Mine in Penglai.Nonuniform sounding grid is constructed.The Wenner array sounding data are collected by high density resistivity instrument,and the array data are converted into symmetrical quadrupole sounding data format.The three-dimensional resistivity inversion data format is established by using the survey grid,and the three-dimensional resistivity inversion is carried out.The error between the central burial depth of minedout area and the threedimensional resistivity inversion of low resis-tivity body is 3.1 m by drilling verification.The final inversion iter-ation accuracy is 9.5%different from that of two-dimensional high density resistivity profile inversion,which provides information for accur-ate dr-illing layout.