Summary
Full wavefield migration (FWM) is an inversion-based seismic imaging method that aims at using the complex wavefields in illuminating the subsurface. Instead of simply propagating a source-side wavefield, as in Primary Wavefield Migration (PWM) method, FWM utilizes the complex wavefield that also includes all transmission effects and all kinds of multiples. This is done by a modeling scheme that considers reflectivity as a scattering generator. The additional advantage of such method is that, although a smooth background migration velocity is used, all the scattering can be still generated, which is not achievable by using finite-difference or finite-elements modeling tools. In this paper we consider the three-dimensional extension of the mentioned algorithm. One of the additional challenges of the 3D extension is the memory usage. Therefore, we consider the implementation of blended acquisition.
Summary
FWM aims at explaining the reflection data in terms of a reflectivity distribution in the subsurface (Berkhout, 2012; Davydenko and Verschuur, 2013). These reflection coefficients, in turn, are iteratively estimated, by applying the imaging condition on source-side and receiver-side modeled wavefields. The main feature of FWM is that it is a full wavefield inversion method, where its modeling tool generates the scattering based on the current reflectivity image, while velocities are only required for the propagation effects. The benefit of this method is that all kinds of multiples and transmission effects will be taken into account while a smooth background model is being used.
Imaging of surface multiples has been already widely implemented (Berkhout and Verschuur, 2006; Tu et al., 2011; Lu et al., 2011). In general this approach is based on re-injecting the measured data after multiplication with the free-surface reflection coefficient (˜ -1). Such approach is very useful in extending the illumination and works well in the marine scenario.
