3D Shallow Water Demultiple - Extending the Concept

The demultiple of seismic data acquired in shallow water environments can be particularly challenging, especially in three dimensions. It is therefore important to be able to utilise a wide range of methods in both the multiple prediction and subtraction phase of the processing sequence. We illustrate this importance by discussing the implementation of a 3-D wavefield extrapolation method for multiple prediction in shallow water. In the case shown, this method utilises a depth migrated section to provide the optimum reflectivity model of the subsurface. In the multiple subtraction phase of the processing sequence, it is shown that optimal results may be obtained by utilising a weighted simultaneous adaptive subtraction methodology. This methodology is used, in the case study described within this paper, to provide the optimum multiple attenuation in a shallow water situation, based on 3-D multiple models from both convolutional and wavefield extrapolation approaches.