Amplitude and AVO Anomalies in 3D Prestack Depth Migration - Critical Analysis Using Raytrace Modelling

3-D Prestack Depth Migration has greatly improved our ability to image reservoirs in complex areas, such as below salt and carbonates in the North Sea or beneath salt bodies in the Gulf of Mexico. But what effect does the overlying structures and abrupt velocity variations have on seismic attributes such as amplitude anomalies or amplitude variation with offset (AVO)?