Development of a versatile algorithm for 2D DC resistivity modelling in the space domain

Abstract

Abstract 2D direct-current resistivity modelling is generally done in the wavenumber domain to efficiently accommodate the 3D character of the source. For faster computation, the wavenumber domain solutions are calculated at around half a dozen wavenumbers. However, the collection of wavenumbers and associated weights that are selected has a significant impact on the accuracy of the solution that is thus obtained in the space domain. It has been shown in numerous forward modelling studies that selecting effective wavenumbers is difficult, particularly for complex models, including topography, anisotropy, and high resistivity contrasts. In this study, we develop an optimized strategy to omit the dependence of the 2D modelling problem on the wavenumbers. Instead of using the wavenumbers domain approach, the problem is solved in the space domain using a new boundary condition derived in this study. It requires only a few grids in the direction perpendicular to the profile. Several numerical experiments are conducted to conclusively demonstrate that the developed algorithm is robust and versatile concerning subsurface and survey parameters.