Reghosted 4D and 3D Reservoir Characterization Using a Broadband Monitor on a Deep Offshore Turbiditic Field

On a deep offshore turbiditic field covered by a recent yet conventional 4D baseline, a non-conventional route has been decided for the first monitor, to obtain seismic information related to dynamic heterogeneities but also better characterize reservoirs. The strategy decided for the first monitor (M1), one year after first oil, was to shoot broadband and process twice: - One 4D-dedicated processing mapped to conventional (with a Fast Track and a Full Processing phase) in order to match the baseline characteristics and obtain quality 4D signal to help understanding the early dynamic behaviour of the field. - One 3D broadband processing aiming to improve the existing seismic for reservoir characterization purposes. Despite a complicated workflow involving the generation of a reghosted dataset for 4D purposes, the final 4D data were produced in 4 months. The 3D broadband processing took 10 months overall. Beyond demonstrating that high quality 4D signal can be obtained by reghosting a broadband monitor on a conventional 4D baseline, it is shown that an unprecedented level of detail of dynamic heterogeneities and reservoir description can be reached in this setting using the combination of high resolution 4D fractional velocity change with 3D broadband images.