f DMO Algorithm considerations applicable to optimum imaging of Central Graben Salt Domes

The salt domes of the Central Graben are surrounded by sediments which have a velocity that is neither constant nor gently increasing. The dramatic increase in interval velocity that occurs at the top of the surrounding chalk, presents a problem for conventional DMO algorithms and, in the vicinity of the dome, often generates spurious high amplitude seismic energy that can not be imaged by current migration techniques. This paper suggests a cause of this spurious signal and a DMO application is demonstrated that is capable of overcoming the problems of the severe velocity gradient and, in so doing, eliminating the spurious high amplitude data from the stack.