SUMMARY

One of the fields in the Norwegian Sea has been imaged several times over the past decades, both with conventional narrow azimuth seismic surveys as well as with ocean bottom seismic. The extensively faulted structure of the field and the possible presence of a salt diapir cause imaging problems in some areas. Therefore, a simulation study has been initiated to judge whether or not a marine full azimuth acquisition geometry improves the image of the subsurface. For this simulation study, simplified velocity and density models of the field were created, containing the main features characterizing it, as well as the problem areas. The simulation was done with 3D finite difference (FD) modeling. Data sets with and without free surface multiples were generated, and imaging from a full azimuth acquisition geometry was compared with imaging from a conventional narrow azimuth geometry. FD modeling shows that the full azimuth design generally leads to a better suppression of noise in the data, mainly due to increased fold. Depth slices show that fault edges are imaged sharper in a full azimuth geometry. Also, the image of and below the salt/limestone structure is improved. However, attenuation of multiple energy due to increased cross line fold is less than expected, except for the first seabed multiple. The low maximum frequency used in FD-modeling may have limited the increase in image quality with the full azimuth modeling