3D controlled-source electromagnetic modeling in anisotropic medium using edge-based finite element method

Abstract

This paper presents a linear edge-based finite element method for numerical modeling of 3D controlledsource electromagnetic data in an anisotropic conductive medium. We use a nonuniform rectangular mesh in order to capture the rapid change of diffusive electromagnetic field within the regions of anomalous conductivity and close to the location of the source. In order to avoid the source singularity, we solve Maxwell's equation with respect to anomalous electric field. The nonuniform rectangular mesh can be transformed to hexahedral mesh in order to simulate the bathymetry effect. The sparse system of finite element equations is solved using a quasi-minimum residual method with a Jacobian preconditioner. We have applied the developed algorithm to compute a typical MCSEM response over a 3D model of a hydrocarbon reservoir located in both isotropic and anisotropic mediums. The modeling results are in a good agreement with the solutions obtained by the integral equation method.

A Parallel Tool for Numerical Approximation of 3D Electromagnetic Surveys in Geophysics

“…In EM field formulations with FEM and EFEM and in order to capture the rapid change of the primary current, the anomalous formulations are desirable [5]. In the anomalous field formulation the total field is decomposed into primary field (background) and secondary field [24]:…”

A multi-domain decomposition-based Fourier finite element method for the simulation of 3D marine CSEM measurements

“…Direct matrix solvers for large geophysical 3D forward problems [33,28,30,26,24,14,19,8,35,2,15] can be computationally expensive, both in terms of memory and CPU time. A way to overcome this limitation is by reducing the dimensionality of the problem, namely from 3D modeling to a 2.5D [23], 2D [4] and/or 1D [20] approximations that are only suitable for particular geometries.…”

Three-dimensional parallel edge-based finite element modeling of electromagnetic data with field redatuming

“…The finite element method is one of the most flexible to model the complex geoelectrical structures (Schwarzbach et al, 2011;Puzyrev et al, 2013;Cai et al, 2014). In the recent years, the edge-based finite element method, which was originally introduced by Nédélec (1980), gained the interests of the geophysical community for 3D modeling of the EM fields (Silva et al, 2012;Cai et al, 2014).…”

“…In the recent years, the edge-based finite element method, which was originally introduced by Nédélec (1980), gained the interests of the geophysical community for 3D modeling of the EM fields (Silva et al, 2012;Cai et al, 2014). The edge element approach is characterized by better properties, such as automatic enforcement of tangential field continuity and divergence free condition, for the simulating of electromagnetic field compared to the conventional nodebased finite element method (Jin, 2002).…”

“…This is especially important in applications of controlled source EM methods in mineral and oil exploration (Ward and Hohmann, 1988;Zhdanov and Keller, 1994;Constable and Srnka, 2007;Um and Alumbaugh, 2007;Andréis and MacGregor, 2008;Zhdanov, 2009;Zhdanov, 2010;Cai et al, 2014;Zhdanov, 2010).…”