3D Joint Inversion of Marine Magnetotelluric and Controlled-source Electromagnetic Data

Abstract

Magnetotelluric (MT) data naturally manifests itself as noise in marine controlled-source electromagnetic (CSEM) data. It follows that MT data can be extracted from measured CSEM data for the relatively negligible cost of additional data processing. MT data has a lower yet broader frequency content relative to the higher and narrower frequency content of CSEM data. Moreover, MT and CSEM methods are sensitive to different geological structures. With the availability of complimentary data sets, we present a new approach to the 3D joint inversion of both CSEM and MT data. Our method is based on the 3D integral equation method for modeling, and focusing regularized inversion. Our examples of a hydrocarbon-bearing reservoir adjacent to a salt dome show that joint CSEM and MT inversion has better model resolution compared to CSEM or MT inversion alone.