Image-guided tomography: structure conforming inversion for complex overburden

Guy Hilburn, Yang He, Francis Sherrill, Taejong Kim and Zengjia Yan present a highresolution tomography method which flattens gathers reliably and quickly, while yielding geologically plausible velocity models. Traditional methods of updating velocity models by seismic tomography rely on a number of assumptions and simplifications. In many situations, these may either increase the amount of time or number of tomographic iterations required to flatten events in migration gathers, or even make gathers worse. In other cases, the velocity models obtained with these techniques may turn out to be physically unlikely, as they do not rely on prior geological knowledge. We have developed a high-resolution tomography method called image-guided tomography (IGT), which is composed of two key ingredients: inversion preconditioned by image-guided interpolation (IGI) and an offset-dependent residual moveout (RMO) picking technique. IGT flattens gathers more reliably and quickly than traditional methods, while yielding more geologically plausible velocity models.