Utilizing Shallow Water PP-PS Seismic of Sparse Ocean-bottom Nodes for Improved Reservoir Characterization

Summary Ocean bottom node (OBN) seismic is getting more popular for providing greater interpretation certainty in areas of complex reservoirs. Its full azimuth (FAZ), high fold count, high repeatability and broadband character prove to be beneficial especially in areas with complex geological structures and these factors were a driver to record the first 4C OBN survey in D1 field, western offshore India. Despite several attempts of reprocessing legacy narrow-azimuth marine seismic with more advanced processing techniques, it was difficult to use the legacy data to resolve the thin plays of the multi-layered limestone reservoir and understand fluid distribution in the reservoir section. We present a case study of seismic processing of PP-PS data, acquired with sparsesly distributed multicomponent ocean-bottom nodes in a shallow water environment, in order to resolve the production issues, anisotropy mapping, reservoir development, thin pay mapping and basement fracture detection. We review a number of processing and imaging challenges and demonstrate corresponding solutions using optimum processing workflows that produced a cleaner and higher resolution final image with improved reservoir characterization.