Velocity analysis with multiples — NMO modeling for layered velocity structures

Several method exist to invert for a velocity model from seismic data. Most commonly used methods are defined in the image domain. However, some methods that are defined in the data domain also exist. In this paper we review and compare a few methods on synthetic data, using the convolutional model and NMO traveltimes to model the data. Special attention will be given to the behavior of the different methods in the presence of multiples. In traditional MVA methods these usually pose a problem since multiples are not flattened or focused for the correct velocity model. In the data domain multiples do focus for the correct velocity model if they are correctly modeled. This is illustrated with a simple example. Another simple example illustrates how ideas from waveform inversion and data-domain velocity analysis can be combined to obtain the correct velocity model and reflectivity from synthetic data with multiples.