True‐amplitude beam migration

Abstract

We develop a simplified theoretical treatment of asymptotic ray‐based beam inversion for common‐offset. We apply the theory to the development of a true‐amplitude imaging algorithm using Gaussian beams. The theoretical treatment is valid for arbitrary velocity variations, and we find that the amplitude behavior of our algorithm is reasonably close to true‐amplitude common‐offset Kirchhoff inversion. We give a further example of the application of our algorithm to imaging the Atlantis structure in the Gulf of Mexico (GOM). In areas where illumination is poor, asymptotic beam and Kirchhoff inversion do not apply, and migration deconvolution or dip equalization is required. We derive the form of the Hessian for common‐offset Gaussian beam migration, and use it to produce inverse migration deconvolution operators for the same Atlantis GOM structure.