A Comparison of Different Methods of Velocity Analysis in Reflection Seismic Data Processing with AVO Anomalies

In this paper, four methods of velocity analysis including Energy-normalized crosscorrelation (EC), differential semblance (Θ), conventional semblance (CS) and AB semblance (α) are compared with each other to determine which of them is able to detect events with class II AVO. The equations of different methods are described, coded and then applied to synthetic data. “Contrast, velocity distinction and time distinction” are three new criteria which have been used to compare the results of these methods. In the next step, all the above methods are applied to real data which belongs to one of the southern oil fields in Iran. Finally, AB semblance led to the best results and in contrast to others, does not stretch velocities and detects shallow events as clear as deep events. It can be concluded that AB semblance method can calculate the velocities of overlapped events with polarity reversal. Furthermore, compared to other methods, this method is able to detect closed events with polarity reversal with more resolution