3D Iterative Migration of Marine Controlled–source Electromagnetic Data with Focusing Regularization

We present our implementation of an iterative migration algorithm for marine controlled-source electromagnetic (MCSEM) data based on the 3D integral equation method with inhomogeneous background conductivity and focusing regularization with a priori terms. The use of focusing stabilizers makes it possible to recover subsurface models with sharper geoelectric contrasts and boundaries than can be obtained using traditional smooth stabilizers. The method is implemented in a fully parallelized code which makes it practical to run large-scale 3D iterative migration within a day on multi-component, multi-line MCSEM surveys for models with millions of cells. We present a suite of interpretations obtained from different iterative migration scenarios for a synthetic 3D MCSEM survey computed from a very detailed model of stacked anticline structures and reservoir units of the Shtokman gas field in the Russian sector of the Barents Sea.