| Popis: |
Using conversion point offsets of converted waves (Cwaves), we present a method for robust estimation of effective gamma, a critical parameter for migrating C-wave events into their correct spatial locations in isotropic or anisotropic media. Unlike P-waves, the ray-paths of Cwaves are asymmetric. This makes it possible to obtain spatial mismatch from positive and negative commonoffset gathers. Although the conversion point offset equation used here is for a stratified media, our numerical analysis has shown that the inversion is relatively independent of dipping of reflectors, as long as relative mismatch is measured by cross-correlation type of analysis. The validity of the methodology is demonstrated through both synthetic and field data examples. This analysis technique aims for fast turnaround in C-wave velocity model building. |
