Exploring the detection performance of different array configurations for Multi-electrode resistivity method tomography using a 2.5D finite element method
Multi-electrode resistivity method is equipped with various electrode array configurations.Due to their differ-ent electrode arrangements,various electrode array configurations tend to exhibit significantly varying detection effects under different survey environments.Hence,to achieve satisfactory detection effects using high-resolution electrical res-istivity tomography,it is necessary to explore the strategy for choosing appropriate array configurations targeting differ-ent objects in practical work.Given the high applicability of the method,its forward and inversion calculations remain a critical task.Based on the differential equations to be satisfied by the point source potential in a three-dimensional struc-ture,this study derived the variational problem to be satisfied by the 2.5D potential and conducted the unstructured grid-ding using the Delaunay triangulation algorithm,thus achieving finite-element forward modeling.By combining practic-al applications,this study designed common geological models and performed forward and inverse calculations using Wenner α,Wenner β,Schlumberger,and dipole-dipole arrays,analyzing their detection effectiveness in different envir onments.Key findings are as follows:(1)For the detection of isolated anomalous bodies in an unknown area,the Wen-ner β and Schlumberger configurations,determined by considering the accuracy and efficiency,can yield better detec-tion effects.(2)The Schlumberger and dipole-dipole configurations exhibit higher horizontal resolution and can distin-guish multiple anomalous bodies nearby.(3)For the detection of low-resistivity fractured zones,the Wenner and di-pole-dipole configurations enjoy better performance.(4)For strata with distinct boundaries,the Wennerα,Wennerβ,Schlumberger,and dipole-dipole configurations can all yield encouraging detection results.Therefore,for data collec-tion using high-resolution electrical resistivity tomography,it is necessary to choose multiple array configurations and conduct comprehensive comparisons and interpretations of the forward and inverse modeling results.
Multi-electrode resistivity methodunstructured gridfinite element methodarray configurationgeophysic-al forward and inversion calculationsresistivity