The sensitivity of velocities with elevation change
John C. Bancroft
Elevation and near surface structure distort a time section. These distortions are modified by estimating the corresponding travel time (statics) that are applied to the time section. If these corrections are small enough, they have a negligible effect on the final processed image. If the static corrections are too large, the assumptions for velocity analysis and migration are violated and incorrect velocities may be estimated. These estimated velocities may not represent the structure of the subsurface. If the statics are "reasonable" then the estimated velocities may allow accurate imaging.
The effect of elevation change on RMS velocities is evaluated with the intent of understanding the velocity structure obtained when processing common scatter point (CSP) gathers on a 2D line from the Hussar data set.
Displays show the effect of the elevation change and the total static change on the velocity.