Effects of Acquisition Geometry to 3D Separated Wavefield Imaging

Separated wavefield imaging helps to improve the subsurface illumination when the towed streamer acquisition geometry is properly designed. Compared to the conventional imaging, which uses a full source wavefield generated by an impulse wavelet at the surface, the multiples imaging uses the down-going wavefield recorded at the streamers as the boundary source wavefield. Therefore, the streamer coverage, density and distribution are all crucial to make the method successful. Wide azimuth (WAZ) acquisition is important to record both the down-going (source) and up-going (receiver) wavefields. Anti-parallel shooting helps to image dipping targets of both facing and opposite to the streamer towing direction. Split-spread shooting geometry is optimum for imaging the dipping reflections of all directions. A field data NAZ survey and examples from 3D SEAM synthetics are tested to demonstrate the importance of acquisition geometry to 3D separated wavefield imaging.