First Application of Marine Magnetotellurics Improves Depth Imaging in the Santos Basin, Brazil

Recent subsalt oil discoveries in the deep waters of the Santos Basin, Brazil, have received considerable attention due to the extent of their reserves and by the challenges in exploration and production in such environment. Recently, electromagnetic methods have re-gained attention and changes in technology are making them a powerful tool for challenging imaging environments. A first large Marine Magnetotellurics (MMT) survey was acquired in Brazil by WesternGeco Electromagnetics in cooperation with Observatório Nacional/CNPq and Petrobras. MMT data were recorded at 96 sites along three profiles. One profile extends approximately 148 km along existing seismic. The MMT data were processed and interpreted using an advanced integrated workflow. The main objectives of the survey were to assess the response and quality of MMT data in a wide range of water depths and test the ability of MMT to enhance seismic depth imaging by providing reliable information that will be used to constrain/improve the resolution of the velocity models. We show that the MMT data can clearly enhance resolution and reduce ambiguities of depth interpretation based on seismic. Work is in progress to enhance the MMT interpretation and apply the enhanced MMT model to develop an integrated depth imaging workflow.