3D inversion of marine CSEM data using a fast finite‐difference time‐domain forward code and approximate hessian‐based optimization

Abstract

An inversion methodology for marine controlled‐source electromagnetic (MCSEM) data with approximate Hessian‐based optimization and a fast finite‐difference time‐domain forward operator is presented. Using data from a synthetic hydrocarbon reservoir, we demonstrate that models are reproduced with a spatial resolution determined by the skin depth of the frequencies included in the inversion. Both single and multiple resistive bodies can be resolved in thesubsurface. Using reciprocal treatment and multiple frequencies at each receiver position, the comprehensive inversion sequence of a typical MCSEM survey, which should match the acquired data to within the measurement error, executes within ∼100 iterations, with about 30 iterations per day, requiring at most a few hundred nodes on a parallel cluster.