EXAMPLES

This section gives an example of residual depth migration of a post-stacked depth image. Figure shows a synthetic slowness model that consists of several dipping layers and a low velocity cap over a high velocity dome. A synthetic zero-offset section is generated from this model, as shown in Figure . If we migrate this section with a constant slowness, we will obtain the image displayed in Figure . The images of the shallow reflectors are positioned correctly, because the interval slownesses in these layers are close to the constant migration slowness. On the other hand, the images of the deep reflectors are seriously mispositioned, because the interval slownesses in these layers are considerably smaller than the slowness used in the migration. The low velocity cap causes the images of the bottom of the dome to be flattened.

In order to correct the distortions of the images, I use the algorithm described in the previous sections to calculate the residual migration operator associated with the true slowness model and the initial constant migration slowness. Then, I apply this operator to the distorted image shown in Figure . Figure shows the output of this residual migration process. The distortion of the images of the reflectors in position are completely corrected.