Abstract

The criterion used in depth interval velocity analysis is the flatness of the pre-stack migrated gathers. Unfortunately there are number of subsurface interval velocity models which could equally flatten the migrated gather. Problem of non-uniqueness is inherently associated with the method itself in determining the final Velocity model, be it because of subsurface models or tomography inversion. As we use the flatness criterion for image gather in determining the subsurface velocity model, hence there exists the problem of non-uniqueness in interval velocity determination. There are various factors contributing to the problem. An attempt is made to understand these factors responsible and to see the effects when basic requirement for the input data is not fulfilled. This study tries to investigate these factors by analyzing the data along a 2D line. The study leads to an ambiguous (nonunique) result when basic requirements for input data are not met