Rigorous 3D inversion of marine magnetotelluric data in the area with complex bathymetry

Abstract

Three‐dimensional (3D) magnetotelluric (MT) inversion is an emerging technique for offshore hydrocarbon (HC) exploration. In this paper we introduce a new approach to 3D inversion of MT data for offshore HC exploration based on the integral equation method. The method is implemented in a fully parallel computer code. We have applied the developed method and software for the inversion of marine MT data collected by the Scripps Institution of Oceanography (SIO) in the Gemini Prospect, Gulf of Mexico. The inversion domain was discretized into 1.7 M cells. It took 9 hours to complete 51 iterations on the 832 processor cluster with a final misfit between the observed and predicted data of 6.2%. The inversion results reveal a resistive salt structure which is confirmed by a comparison with the seismic data. These inversion results demonstrate that we can map resistive geoelectrical structures like salt domes or HC reservoirs with reasonable accuracy using 3D inversion of marine MT data.