Wave equation vector migration for subsalt VSP imaging and interpretation

Abstract

Interpretation of subsalt VSP data is a challenge due to low fold, uneven illumination, and the resulting presence of a large amount of migration artifacts. We propose a wave equation vector migration algoritm (VWEM) to exploit the potential of multi-component VSP surveys for imaging in complex subsalt environments. The algorithm naturally takes into account multi-pathing and is designed to enhance true events in VSP images. We also propose a noise imaging algorithm that enhances noise and suppresses true events to consistently characterize migration noise in VSP images. Joint interpretation of vector and noise images enables clear identification of true and false events. The approach was successfully applied to a 3D VSP acquired in the Gulf of Mexico in order to clarify the subsalt scenario.