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In many deep-water oil and gas reserves around the world, significant reservoirs are often trapped in the vicinity of salt bodies. Accurate mapping of the salt flank and sub-salt structures is a critical task for exploring and characterizing the reservoirs. The steep sides of an irregularly-shaped salt dome are difficult to image accurately using surface seismic alone. Thus, threecomponent (3C) VSP surveys are usually acquired to improve the image of reservoir structures.We demonstrate a VSP imaging application in the South Louisiana Salt Basin, USA. An offset VSP (OVSP) and a refraction salt proximity (SP) survey were simultaneously acquired and processed to image a steep salt boundary and updip sediment reflectors. We use both transmitted P-P and P-S converted waves from the SP survey to calculate the 3D salt exit points that delineate the steep salt face. Furthermore, we develop a robust method for estimating the Vp/Vs ratio of the sedimentary rocks flanking the salt dome. The 3C OVSP data was processed to extract the reflection-converted PP and PS waves from the steep salt interface and updip sediment reflectors. Using a velocity model derived from the check shot data and the estimated Vp/Vs ratio, we migrated the extracted reflection data to create depth images of the salt face and the nearby structures. The migrated images using both PP and PS converted waves provide a precise definition of the steep salt face and the reservoir sands flanking the salt dome. This study also indicates that both reflection and refraction surveys can provide a consistent location of the steep salt flank, demonstrating the strength of combining these VSP techniques.

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