Fast and High Precision Numerical Simulation of DC 2.5D under Multi-source Condition

Fast and high precision numerical simulation under multi-source condition is the key to two and a half dimensional (2.5D) high efficiency and high precision inversion of DC resistivity method. In this paper, a 2.5D multi-source fast and high-precision numerical simulation method based on DC resistivity method is proposed, which can be applied to arbitrary scale and complex geoelectric model. Firstly, the boundary conditions are transferred to make the coefficient matrix independent of the position of the source. On the premise of using the direct solution method to solve the linear equations, the fast back-substitution solution is realized under the multi-source condition. Secondly, a set of wave number selection method that can be adapted to arbitrary scale model is proposed, and the inverse Fourier transform is calculated by using the finite element method. And also, the potential value in the spatial domain of any lateral section is calculated. Finally, an effective solution to the singularity of the field source is proposed. The numerical simulation algorithm shows that the 2.5D numerical simulation of DC resistivity method under multi-source condition proposed in this paper has the characteristics of fast calculation efficiency, high numerical calculation accuracy and high numerical stability.