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Using Full Waveform Inversion to Update Anisotropy - A North Sea Case Study
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Full Waveform Inversion (FWI) aims to obtain high resolution velocity models by minimizing the misfit between observed and modelled data. While FWI algorithms that take into account anisotropy are often used in the industry, it is still common practice to update for vertical velocity only, keeping the anisotropic parameters fixed during the inversion. The main advantage of such an approach is mitigating the different sensitivity of the data to the parameters that characterize the subsurface. Nonetheless, fixing the anisotropic parameters imposes a constraint on the update of the vertical velocity, potentially leading to a sub-optimal solution of the inverse problem.
Here we formulate the inverse problem within the Vertical Transverse Isotropy (VTI) model, and present an approach for updating both vertical and horizontal velocities. The necessary theory for the implementation of the algorithm is reviewed and developed within the scope of this work and a practical application to a North Sea field dataset is then presented. Our FWI result reveals velocity and anisotropy details associated with shallow channels and other features in the near surface geology.