THE EFFECT OF 2-DIMENSIONAL TERRAIN WITH POINT-SOURCE ON RESISTIVITY SURVEYS

This paper uses the boundary element method to solve the problem of the effect of two-dimensional terrain with point current source on resistivity surveys. First, the 3-D boundary value problem of the electric field of a point source on 2-d terrain is converted into a 2-D boundary value problem using a Fourier transform. Then, the 2-D boundary value problem is transformed into a boundary integral equation by means of Green's formula. The boundary element method is used to solve the integral equation. Finally, using an inverse Fourier inverse transform, we get the electric potential in 3-D space. ExamPles calculated for two terrain models show that the results from this method compare well with those from analytic and finite element method. If the terrain has a clear strike, this method can be used for terrain corrections for resistivity surveys. An example of a terrain correction for electric sounding is given. This method can be run on a personal computer and takes a few minutes to correct a profile of data on an IBM AT -grade computer.