Velocity sensitivity of subsalt imaging through regularized inversion

Marie L. Clapp

marie@sep.Stanford.EDU

ABSTRACT

The effects of inaccurate velocity models on migration are well known. Accurate velocity models are most difficult to obtain in complex areas where iterative inversion can provide a better image than migration. This paper investigates the velocity sensitivity of a regularized inversion scheme that explicitly assumes that the correct velocity is being used. This inversion uses a regularization operator that assumes that there is no moveout along the offset ray parameter axis. Experiments performed with various incorrect velocity models indicate that this assumption is valid for velocity models that can be reasonably produced by common velocity analysis techniques. Velocity models that are very inaccurate cause the inversion process to reject attempts by the regularization to produce an image that is inconsistent with the data.