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Angle domain results

Now, I apply the same method in the angle domain as opposed to the zero-offset image domain. The angle panels are created after migration from the offset panels directly Sava et al. (2001); Sava and Fomel (2000); Stolt and Weglein (1985); Weglein and Stolt (1999). I show in Figures [*] and [*] the angle gathers at two locations of the model (3050 and 5550 m) for the migration result (${\bf m1}$), the filtering result (${\bf \hat{b}*m_1}$) and the inversion result after five CG iterations. Again, the angle gather after filtering has less artifacts than with inversion with a similar amplitude pattern throughout the section. In Figure [*], we notice that the filtering approach improves the continuity of some reflectors (between 500 and 600 m.) and that the amplitude increases for large angles. This behavior is similar to what Sava et al. (2001) observed for wave equation migration with amplitude corrections. I display in Figure [*] the estimated filters for the angle gather in Figure [*]. Again, we see that we have higher amplitudes for filters at large aperture angles. In addition, we notice a smoothing effects of the filters along the angle axis.

Finally I show in Figure [*] a comparison of stacked images across angle for ${\bf
 m_1}$ and ${\bf m_2}$. The bottom reflectors are stronger than in Figure [*] with fewer migration artifacts, as expected from the stack. The differences between the two stacked-data panels in Figure [*] are similar to what we observe in Figure [*], i.e, stronger amplitudes at the top of the image for ${\bf
 m_1}$ and fewer migration artifacts for ${\bf m_2}$.In Figure [*], I display a comparison between the inversion and filtering approaches for the stacked data. Again, the amplitude pattern is the same for both images with far less artifacts in the filtering result (Figure [*]b).


next up previous print clean
Next: Discussion Up: Migration results Previous: Zero-offset prestack migration results
Stanford Exploration Project
7/8/2003