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

This paper presents a linear edge-based finite element method for numerical modeling of 3D controlled-source 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. HighlightsThis paper develops a novel formulation of the edge-based finite element method for 3D modeling of marine CSEM data in anisotropic conductive medium.The method uses the edge-based vector basis functions, which automatically enforce the divergence free conditions for electric and magnetic fields.The developed method is effective in modeling the seafloor bathymetry using hexahedral mesh.

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