Resolving fault shadow problem by Fault Constrained Tomography

Abstract

In many areas, so-called, Fault Shadows is a serious hindrance to successful seismic imaging. The major part of this problem is caused by large velocity variations in fault zones. Fault zones contain different types of geological and imaging velocity anomalies that cause seismic image distortions and non-hyperbolic moveout. Pre-stack depth migration with the proper velocity model is the only method that can solve this problem and improve the seismic image below fault zones. We have developed a special and novel technique, Fault Constrained Tomography, to build high-resolution interval velocity models that are required for fault areas. Fault Constrained Tomography takes into account the nature of velocity variation within fault zones. Combined with Pre-Stack Depth Migration it can successfully remove fault shadow distortions from seismic images.