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Complex Three-dimensional Surface Representation and Linearization for Full Waveform Inversion
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 74th EAGE Conference and Exhibition incorporating EUROPEC 2012, Jun 2012, cp-293-00423
- ISBN: 978-90-73834-27-9
Abstract
Full waveform inversion (FWI) provides a powerful mechanism for building complex seismic velocity models, with the potential to resolve high-resolution structure. FWI methods generally operate on a gridded representation of a seismic velocity model. However, many models used in FWI contain complex bodies (e.g. salt intrusions) that generate a large, sharp contrast in seismic properties. Refining these with FWI can prove extremely difficult when they are represented implicitly within a gridded velocity model. The constraints on model updates required at surfaces to optimise convergence are different from those required elsewhere. It is difficult to account for this difference correctly when the surfaces have no separate representation. The method described in this paper maps full waveform inversion model updates for seismic parameters to updates in the position and shape of surfaces within a 3-D model. This allows surfaces to be represented, refined and constrained explicitly during waveform inversion. The link between structural and gridded models allows ray-based constraints from tomography to be incorporated directly as constraints in FWI to increase the stability and improve the convergence of the inversion process.