A parallel finite-element method for three-dimensional controlled-source electromagnetic forward modelling

We present a nodal finite-element method that can be used to compute in parallel highly accurate solutions for 3-D controlled-source electromagnetic forward modeling problems in anisotropic media. Secondary coupled-potential formulation of Maxwell’s equations allows to avoid the singularities introduced by the sources, while completely unstructured tetrahedral meshes and mesh refinement support an accurate representation of geological and bathymetric complexity and improve the solution accuracy. Different complex iterative solvers and an efficient preconditioner based on the sparse approximate inverse are used for solving the resulting large sparse linear system of equations. Results are compared with the ones of other researchers in order to check the accuracy of the method. We demonstrate the performance of the code in large problems with tens and even hundreds of millions of degrees of freedom. Scalability tests on massively parallel computers show that our code is highly scalable.Funding for this work was provided by the Repsol-BSC Research Center. The authors acknowledge Repsol for permission to submit this paper. All numerical tests were performed on MareNostrum Supercomputer of the Barcelona Supercomputing Center. VP wishes to express his gratitude for hospitality during his visit to Texas A&M University. The authors would like to thank Dr. Christoph Schwarzbach for providing additional information on their results and the Editor, Dr. Gary Egbert, and two anonymous reviewers for their suggestions that helped to improve the presentation of this paper.Peer Reviewe