Fast Forward Modeling of Resistivity Method under Complex Topography Using Finite Element Method

A parallel finite element scheme for 3D resistivity method forward modeling is introduced in this article. The domain decomposition algorithm, along with a message passing interface, is used to implement parallelism. The computational domain is divided into subdomains, and mesh partitioning is combined with load balancing. Unstructured meshes and local mesh refinement strategies are used to realize high precision for complex topography models. Furthermore, an improved linear solver for multi-electrode resistivity method modeling is adopted. Recycling preconditioned conjugate gradient, which is a linear solver, is based on the similarity of linear systems between point sources. The multiple right-hand-side linear systems corresponding to different point source positions are constructed, and the accelerated convergence is obtained through recycling subspace using the linear solver. The computational accuracy and efficiency of the forward scheme for complex topography models are verified using the numerical test results.