Next generation CSEM inversion and modelling

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Subsurface resistivity mapping based on Controlled Source Electromagnetic (CSEM) measurements is an attractive technology for exploration as it offers the possibility to distinguish between hydrocarbon and brine bearing prospects where conventional seismi c methods tend to prove inconclusive. This enhances the explorationist´s understanding of the target geology and assessment of pre-drill risk. Using the same principles as electromagnetic well logging, marine CSEM uses the responses of electromagnetic fie lds to probe buried structures from the seafloor. CSEM employs a strong electric field source towed near the seabed to sample electric and magnetic field responses over a large area. From this data CSEM yields information about subsurface resistivity at l arge scales over geometries typical of oil and gas fields. The goal of this R&D project is to increase the value proposition of marine CSEM as an efficient and trustworthy exploration technology. The planned innovations will significantly improve the ima ges of the subsurface that are available prior to drilling, and as a result enable increased drilling success rates for the energy companies, throughout the E&P workflow. The impact of the planned innovations is most prominent in more accurate and effici ent 3D CSEM inversion methods. This will result in less time spent on building initial models, increased confidence in inversion results and optimal value of full-azimuth 3D data. Easier interpretation due to superior inversion results and improved integr ation with seismic data will make EMGS a technology leader in 3D CSEM inversion. The main innovations in this project are the expected research results with respect to numerical algorithms for inversion of extremely large non-linear systems. Although the solution algorithms will be studied in the context of CSEM, the underlying numerical methods will fundamentally impact other communities researching inversion of large non-linear systems.