Paper Summary
This paper develops a fast and efficient large-scale anisotropic inversion technique for towed streamer electromagnetic (EM) data, which incorporates seismic constraints. The inversion algorithm is based on the 3D contraction integral equation method and utilizes a re-weighted regularized conjugate gradient technique to minimize the objective functional. We have also introduced the concept of a moving sensitivity domain for seismically guided EM inversion, originally developed for airborne EM surveys, which makes it possible to invert the entire large-scale towed streamer EM survey data while keeping the accuracy of the computation of the EM fields. The developed algorithm and software can take into account the constraints based on seismic and well-log data, and provide the inversion guided by these constraints. Application of this method for the interpretation of about 2000 line km of towed streamer EM data over the Barents Sea demonstrates a practical effectiveness of this approach for large-scale inversion of marine EM data.