2D,3D Finite-Difference Forward Calculations Of High-Density Resistivity Method

The DC resistivity method is based on the difference of the resistivity of rocks and minerals in the earth. It is one of methods to solve the problems of geological exploration and prospecting through observe and study the electrical distribution of artificial established geoelectric field. High‐density resistivity method achieve the field data collection rapid and automated.It is developed from the basis of the DC resistivity method, the main features is the use of intensive measurement points and a variety of measuring devices. Forward calculations obtained the distribution of computing electric field through geoelectric dmodel with known location of electrical source. Now,2D and3D high‐density electrical forward problems have been the research focus of the electrical method, it can give the apparent resistivity distribution characteristics of underground geoelectric section, and be in favor of guidance the inversion interpretation.This paper summarizes the previous high‐density electrical prospecting instruments and various methods of forward calculation. It use the finite‐difference method to achieve the2D finite‐difference forward calculation，and then use Wenner electrode configuration to measure apparent resistivity’s distribution.,The results of analytical method and numerical calculation method are compared to verify the correctness of the forward algorithm. Create a variety of theoretical dmodels and use the finite‐difference to achive forward calculation, re‐use the dmodels with the Res2Dmod software, then analyze the apparent resistivity values and further validate the precision of the finite‐difference calculations.On the basis of2D finite‐difference forward calculation，this paper has achieved the forward calculation of three‐dimensional dmodel. And compared the apparent resistivity contrast with the Res3Dmod software on several typical3‐D geoelectric dmodel.The result is that the abnormal response is basically consistent. Come to the conclusion, in this paper,2D and3D forward calculation method can be used to study the abnormal characteristics of the geological dmodels，and also provides a powerful and reliable tool for future research on inversion method.