Slight depression in the velocity grid and variable vertical grid steps are not critical for the inversion and are presented in order to emphasize the flexibility of the parameterization. Note that since our CIG picks were done in depth, their positions also indicate the imaged reflectors. In driving the above ray-tracing, we should prefer rays that are specular , which means that obey Snell's law during reflections from interfaces. After each of 31 dip filtering steps at varying angles, trace envelope of the resulting image was calculated, and maximum amplitude was selected at each grid node. Amplitude peaks in this map point to strong specular reflections.
Blue areas correspond to positive dips in the migrated image, red areas indicate negative dips.
Compared to the starting model, this model has reduced velocities in the right part of the model and increased velocities below the depth of 8 - 10 m. Also note increased image amplitudes within the channel. Dashed black line indicates the top of clay horizon interpolated from well data.