Illumination from 3D imaging of multiples: an analysis in the angle domain

Angle domain common image gathers provide information for velocity model building and amplitude versus angle(AVA) analysis. They require good angular illumination to deliver reliable results. The main acquisition parameter affecting angular illumination is the shot density, which can be coarse in conventional marine towed-streamer acquisition. Imaging of multiples can help mitigate the problem, as it employs the down-going wavefield as an areal source. The areal source augments source density when compared with the point source used for imaging of primaries. We apply Separated Wavefield Imaging (SWIM)to create angle domain common image gathers from sea surface-related multiples. Imaging of multiples improves the angle gathers in the coarser sampled direction, e.g. 90-degree azimuth. We demonstrate these concepts by using a wide azimuth (WAZ) field data example.