Optimizing the grouping of shots for shot-record migration
Scott Morton, Mingjuan Shi, Jacques P. Leveille, Mike Oyler · 2008
Shot-record pre-stack depth migration is a standard component of our seismic imaging toolbox and has a cost proportional to the number of shots migrated. A decade ago we migrated using one-way approximations to wave propagation, commonly called “wave-equation migration”, and frequently only used a fraction of the shots to control the computational cost. Today, we routinely run multiple iterations of wave-equation migration using all the shots. However, reverse-time migration, using the more accurate two-way propagation approximation, is very expensive with today's computers when all the shots are used. Rather than migrating a subset of the shots, it is common today to combine nearby shots into a “super-shot” which can be migrated at the cost of a single shot. One simple method for creating a super-shot is to bin the shot locations. In this paper, we present an algorithm for optimizing the grouping of shots, generally resulting in fewer super-shots and/or less shot movement when compared with shot binning.