Water-bottom and diffracted 2D multiple reflections in data space and image space

Gabriel Alvarez

gabriel@sep.stanford.edu

ABSTRACT

Water-bottom multiples from a dipping interface have the same kinematics in a Common Midpoint (CMP) gather as a primary from a reflector with twice the dip at twice the perpendicular depth at the CMP location. When migrated with the velocity of the primaries, these multiples are overmigrated just as primaries migrated with higher velocity, and their moveout is thus predictable in image space. Diffracted multiples, on the other hand, have an apex-shifted moveout in CMP gathers and a more complicated, also apex-shifted, residual moveout in image space when migrated with the velocity of the primaries. I illustrate the moveout of water-bottom and diffracted multiples in image space with a simple 2D synthetic dataset.