Getting closer to the geology contrasts by starting stratigraphic inversion with velocity models from new tomographic methods

Summary The resolution of seismic imaging has long been characterized by a mid-frequency gap between the long vertical wavelength components that can be inferred from travel-time tomography and the short wavelength components that can be inferred from seismic migration. The progress in tomography and in broadband acquisition now allows this mid-frequency gap to be filled and even results in an overlap between the information obtained from migration velocity models and from depth migrated seismic reflection data. Tomographic approaches now provide resolution up to 6 Hz with, in addition, a precise localization of major velocity contrasts. In this paper we discuss the benefits of tomographic approaches for reservoir characterization, where the missing frequencies traditionally come from a velocity model interpolated or extrapolated from well log information. This low-to-mid frequency modeling is critical for estimating absolute rock properties. Replacing a velocity model extrapolated from sparse well information by spatially consistent seismic measurements is of paramount importance.