Abstract

From lead identification in 1998 to discovery in 2008 and subsequent geological appraisal, the understanding of the Freedom subsalt prospect in the Gulf of Mexico has improved as new seismic data acquisition and processing technology became available. Technical limit seismic processing of the best available dataset drove the evolution of the seismic image of this area for many years. We moved from 2D to 3D SRME (surface-related multiple elimination), from vertical update to 3D Tomography, and on to a complete subsalt velocity estimation sequence, isotropic to anisotropic imaging and from Kirchhoff to Beam/WEM (wave equation migration) then RTM (reverse time migration) imaging algorithms. Modeling also played a key role in the evolution of our understanding of the imaging challenges at Freedom, guiding our choices of imaging algorithms, acquisition methods and directions and interpretation strategies. For this particular area, acquisition direction and increased azimuth/offset coverage may have been the most influencing factor but the combination of several processing steps certainly contributed too.