Toward a More Accurate Gaussian Beam Migration - Impact of the Steepest Descent Approximation and the Fold Compensation on Real Data

Acoustic Gaussian beam migration is an attractive imaging method because it is flexible with regards to input geometry; it is efficient, and accurate in imaging multipath arrivals. It can produce results for all types of seismic acquisition, even in the presence of rough surface topography, and provide onboard fast-track imaging, controlled beam for model building, structural imaging, or sophisticated and/or target oriented imaging. Subsequently, one of the hurdles that this method must overcome in production imaging is the evaluation of the impact of the steepest descent (i.e., stationary phase) approximation that is employed to reduce the computation cost. This is important when both the acquisition geometry and the geological setting are complex. Another important aspect of imaging is in fold compensation for irregular acquisition geometries. Real data examples demonstrate the impact of this steepest descent approximation and fold compensation on the illumination and the event continuity in the final image.