We introduce a multi-domain decomposition
Fourier finite element (MDDFFE) method for the simulation
of three-dimensional (3D) marine controlled source
electromagnetic measurement (CSEM). The method combines
a 2D finite element (FE) method in two spatial dimensions
with a hybrid discretization based on a Fourier FE
method along the third dimension. The method employs a
secondary field formulation rather than the total field formulation.
We apply the MDDFFE method to several synthetic
marine CSEM examples exhibiting bathymetry and/or multiple
3D subdomains. Numerical results show that the use of
the MDDFFE method reduces the problem size by as much
as 87 % in terms of the number of unknowns, without any
sacrifice in accuracy.