Viscoelastic Full Waveform Inversion of Sea Bottom Long Offset Seismic Data in Presence of Attenuation
T. Belahi, S.C. Singh and N. Fuji
Event name: 78th EAGE Conference and Exhibition 2016
Session: Full Waveform Inversion (C)
Publication date: 31 May 2016
Info: Extended abstract, PDF ( 1.13Mb )
Price: € 20
Seismic data acquired at the sea bottom are more and more available. It is now possible to record shear and converted waves thanks to this type of data. It opens up the possibility to constrain bot h P- and S-wave velocities with tools such as full waveform inversion (FWI). The data recorded at the sea bottom can be particularly sensitive to attenuation, especially at long-offset, thus often viscoelastic FWI is required. In this study we use a 2D viscoelastic FWI scheme on synthetic data to assess possibility to treat the attenuation parameters as passive parameters of the inversion and still recover acceptable models for P- and S-wave velocities. Alternatively, we assess the inversion of the seismic velocities as well as the parameters controlling attenuation altogether. We find that inverting for all parameters together is necessary to get access to the short wavelength features of the subsurface model because the short-wavelength attenuation model is required to properly treat reflections and converted waves close to the critical angle. Inverting long-offset data in conjugation with a smooth attenuation model is sufficient to yield the long wavelength features of the velocity models.