Edge-based electric field formulation in 3D CSEM simulations: A parallel approach

Abstract

Abstract-This paper presents a parallel computing scheme for the data computation that arise when applying one of the most popular electromagnetic methods in exploration geophysics, namely, controlled-source electromagnetic (CSEM). The computational approach is based on linear edge finite element method in 3D isotropic domains. The total electromagnetic field is decomposed into primary and secondary electromagnetic field. The primary field is calculated analytically using an horizontal layered-earth model and the secondary field is discretized by linear edge finite element method. We pre-calculated the primary field through of an embarrassingly-parallel framework in order to exploit the parallelism and the advantages of geometric flexibility. The numerical-computational formulation presented here is able to work with three different orientations for the dipole or excitation source. Our code is implemented on unstructured tetrahedral meshes because are able to represent complex geological structures and they allow local refinement in order to improve the solution's accuracy. The code's performance is studied through a test of scalability.

Tailored meshing for parallel 3D electromagnetic modeling using high-order edge elements

“…For 3D EM modeling, multiple references use Nédélec FE of low-order polynomial functions (e.g., first-order) (Börner 2010;Farquharson & Miensopust 2011;Mukherjee & Everett 2011;Ren et al 2013;Um et al 2013;Cai et al 2014;Chung et al 2014;Grayver & Bürg 2014;Kordy et al 2015;Castillo-Reyes 2017;Castillo-Reyes et al 2018), and high-order polynomial functions (Schwarzbach et al 2011;Grayver & Kolev 2015;Castillo-Reyes et al 2019;Rochlitz et al 2019). Nédélec FE offer a proper mechanism to discretize the space, H(curl), of the electric vector field.…”