Simultaneous Sources - Continuous Acquisition and Processing for Marine Data

Until recently, seismic data acquisition has been fundamentally limited by the requirement that the delay time between one shot and the next be sufficient to avoid significant contamination of data from one shot with energy from another. Acquisition with simultaneous sources drops this requirement and, therefore, provides potential for enormous improvements in acquisition rates and source sampling. To realize this potential, however, the way we acquire and process data must change.

Although simultaneous-source technology is already a commercial reality for both land and marine acquisition, there is considerable scope for further optimization, especially in the marine case. In this work, I address the specific issue of relaxing the constraint that sources fire nearly synchronously, such that the options for survey design in particular are greatly increased. I show that separation into individual shot records is possible even with arbitrary (asynchronous) shot firing times, provided those times have some randomness to them. Comparisons of synchronous and asynchronous shot separation on data simulated using the SEG Advanced Modelling Program (SEAM) model indicate that the increased randomization in the asynchronous case is very beneficial, despite its necessarily generating zones where the interference is much stronger than the underlying signal.