Imaging tests were conducted on the topographic (WEM) and datumed (Kirchhoff migration) datasets. Figure presents the results of imaging with the TopoWEM approach. Near-surface dipping reflectors are well-imaged, as are those above and at the basement. Note, though, that reflectors are somewhat broken up in some locations, especially in the basement. Angle gathers (not shown here) are generally flat; however, the presence of residual curvature indicates velocity model inaccuracy, and suggests that additional work to improve the currently geologically derived velocity model is warranted.
Figure presents the results of migrating the datumed dataset using a Kirchhoff algorithm. Image quality is good at mid-to-basement depths; however, near-surface reflectors observed in the TopoWEM image are not visible. This could be due to additional internal velocity model smoothing in the proprietary Kirchhoff migration code, or to the failure of the vertical datuming approximation, which distorts wave-propagation paths and defocuses the near-surface image. (A Kirchhoff migration test from topography has not yet been conducted.)