Residual moveout-based wave-equation migration velocity analysis

We propose a new method to perform wave-equation migration velocity analysis by maximizing the flatness of the angledomain common image gathers. Instead of maximizing the image-stack-power objective function directly with respect to the slowness, we link the objective function to the slowness indirectly through an intermediate moveout parameter. This approach is immune to the cycle-skipping problem, and it produces high-quality gradients. In addition, the proposed method does not require explicit picking of the moveout parameters. Our numerical examples demonstrate the great potential of this method: in the first example where there is a Gaussian-shaped anomaly slowness error, our method produces well-behaved gradient; from our test on the Marmousi models, the proposed method converges to a high-quality model that uniformly flattens the angle-domain common image gathers.