Paper Summary

A velocity anomaly zone with high contrasts and small wavelength variations is often a challenge for conventional depth imaging. It requires model details that are usually smoothed out because of the noise present in the data. In the eastern Gulf of Mexico, carbonate karst zones are often found over the Florida Escarpment as shown in Figure 1. The karst zones have significantly slower velocities than the surrounding sediments. The size of these karsts is usually a few meters to a few hundred meters. The resulting seismic images below the karst zones are often poor and non-geological (Figure 2). A synthetic modeling study has been conducted to give more insight into the difficulty of running conventional tomography, and to provide some guidelines for modeling the karst zone velocity anomaly. A new velocity model building technique has been developed that combines karst modeling and horizon-driven tomography. The geological information and interpretation are used as input as well as constraints to seismic tomography. The integration of geological interpretation and seismic tomography enable us to derive a detailed velocity model and improve the seismic image in the area.