Target-oriented wave-equation inversion with regularization in the subsurface-offset domain

Alejandro A. Valenciano

valencia@sep.stanford.edu

ABSTRACT

A complex velocity model can cause shadow zones in an image computed by migration due to poor illumination. These shadow zones may contain weak signals masked by artifacts. To reduce artifacts and recover the real signal, a wave-equation target-oriented inversion scheme can be developed that uses an explicitly computed least squares inversion Hessian. To solve the otherwise ill-conditioned inversion problem a model regularization needs to be added. One choice for regularization is to penalize the energy in the image not focused at zero subsurface-offset. The subsurface-offset Hessian needs to be computed by using the adjoint of migration as the modeling operator. Results on Sigsbee model show encouraging results.