Page 540 - Acquisition and Processing of Marine Seismic Data

11.10 DIP MOVEOUT 531

FIG. 11.41 Processing flow to improve stack quality using DMO. Since DMO removes the conflicting dips issue, quality of
the semblance plots, and hence, accuracy of the velocity analysis after DMO processing is significantly improved.

FIG. 11.42 Velocity spectra (A) before, and (B) after DMO. Accuracy of the velocity picks after DMO is enhanced since
DMO removes the multiple enclosures shown by the dashed rectangle in (A) arising from the conflicting dips.

velocity spectra before and after DMO proces- processors to pick the correct velocity both for
sing. After DMO processing, semblance con- flat and dipping events at the same time. In
tours generally become clearer and better Fig. 11.42A, for instance, there are several multi-
velocity functions are obtained. Removal of ple enclosures approximately coinciding, with
dip dependence of the velocities allows the same zero-offset time of the semblance plot