Conclusions

The results of preconditioned inversion with incorrect velocity models are encouraging. As long as the velocity model is not too inaccurate, the preconditioning operator behaves as it would for the correct velocity model and produces a better image than migration alone. In the case of a highly inaccurate model, the inversion itself prevents us from producing an image that would conflict with the known data. Overall, as long as the velocity model is reasonably close to correct, the assumption of zero moveout made by the preconditioning operator is acceptable.