Full-waveform Inversion Aided Depth Imaging

Full-waveform inversion based on the finite difference approach was originally introduced in the time–space domain (e.g.Tarantola, 1984, Pica et al., 1990, Sun & McMechan, 1992). Inversion can also be implemented in the frequency-domain (Pratt et al., 1998, 1999, Ben-Hadj-ali et al., 2008). The advancement in hardware over the past few years has allowed us to execute 3D FWI on real datasets in marine (Plessix,2009, Sirgue at al.,2009,Vigh et al.,2009,2010) and in land (Plessix,2010) environments. They demonstrate that FWI can be used for velocity updates if the acquired data has adequate low frequency signal and long offsets. The shallow section of the model could be significantly enhanced by the use of FWI, which can result in a much improved depth image over all. One of the challenges with FWI is converging to the local minima, which makes the technique very sensitive to the starting velocity model especially when 3D is considered. To lessen the sensitivity of the initial velocity field, the implementation of FWI at low frequencies using long offsets is required (Bunks et al., 1995, Pratt, 1999).