Chapter 4: Mapping of 3D multiples to image space: Theory and a synthetic data example

The main problem in the attenuation of multiples is with narrow-azimuth towed-streamer 3D data. In this chapter I extend the basic equations for the residual moveout of specular multiples in ADCIGs for 3D data. I show that the mapping of the multiples is similar to the 2D case, except that the crossline dip generates an azimuth dependency that is different for primaries and multiples. I use a simple 3D synthetic prestack dataset with two primary reflections and two specular multiples to illustrate the mapping of the multiples to 3D ADCIGs. Since the 3D ADCIGs are function of both aperture angle and reflection azimuth, their interpretation is not trivial. I describe in some detail the information contained in the 3D ADCIGs and show how the multiples and the primaries have very different residual moveout. This chapter lays the foundation for the application of the method to the real 3D dataset of Chapters  and .