The AMO operator presented in this chapter is a new partial prestack-migration operator that can be efficiently applied to 3-D prestack seismic data to transform their effective offset and azimuth. AMO is a generalization of the migration-to-zero-offset operators (e.g. DMO) because it can transform data to arbitrary offsets and azimuths. By including AMO in the processing flow we can considerably reduce the computational cost of 3-D prestack depth imaging by reducing the size of the data to be migrated.
Results of applying AMO to a marine dataset from the North Sea showed that AMO improves the accuracy of partial stacking over a range of offsets. In particular, the high-frequency steeply-dipping components of the reflected, or diffracted, energy benefit from the application of AMO. These components are crucial for the correct interpretation of complex fault systems, as well as for high-resolution imaging of complex reservoirs.