Abstract

Processing of converted (PS) waves currently adopted by the exploration industry is essentially based on resorting PS data into common conversion point gathers and using them for velocity analysis. Here we explore an alternative procedure. Our key idea is to generate the so-called pseudo-shear (?S) seismograms from the recorded PP and PS traces and run conventional velocity analysis on the reconstructed S data. This results in an effective S-wave velocity model because our method creates the data that possess kinematics of pure shear-wave primaries. Since we never deal with such complexities of converted waves as moveout asymmetry, reection point dispersal, and polarity reversal, these generally troublesome features become irrelevant. We describe the details of our methodology and apply the developed processing flow to a multicomponent ocean bottom cable line acquired in the Gulf of Mexico. Since the obtained stacking velocities of P- and ?S-waves indicate the presence of effective anisotropy, we proceed with estimating a family of kinematically equivalent VTI (transversely isotropic with a vertical symmetry axis) velocity models of the subsurface.