Print Email Facebook Twitter Spectral sensitivity analysis of FWI in a constant-gradient background velocity model Title Spectral sensitivity analysis of FWI in a constant-gradient background velocity model Author Kazei, V. Kashtan, B.M. Troyan, V.N. Mulder, W.A. Faculty Civil Engineering and Geosciences Department Geoscience & Engineering Date 2013-06-10 Abstract Full waveform inversion suffers from local minima, due to a lack of low frequencies in the data. A reflector below the zone of interest may help in recovering the long-wavelength components of a velocity perturbation, as demonstrated in a paper by Mora. Because smooth models are more popular as initial guesses for FWI, we consider the Born approximation for a perturbation in a reference model with a constant velocity gradient. Analytic expressions are found that describe the spatial wavenumber spectrum of the recorded seismic signal as a function of the spatial spectrum of the inhomogeneity. We study this spectrum in more detail in terms of sensitivities. Since the velocity model is inhomogeneous near the perturbation, we need to specify its depth. We compare these sensitivities and find that low frequencies are extremely useful for the first stages of inversion – a well-known fact. However, also the high-frequency data contain some information about the low spatial wavenumbers in the perturbation, which offers opportunities for inversion in the absence of low frequencies in the data. We observe that the longer wavenumbers are better resolved in the deeper parts of the model if large enough offsets are available. To reference this document use: http://resolver.tudelft.nl/uuid:e6c2357e-e8a5-41ca-9759-ca41638d438a Publisher EAGE Source 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013, London, UK, 10-13 June 2013 Part of collection Institutional Repository Document type conference paper Rights (c) 2013 The authors Files PDF 297877.pdf 462.19 KB Close viewer /islandora/object/uuid:e6c2357e-e8a5-41ca-9759-ca41638d438a/datastream/OBJ/view