Ghost notches in various domains

Abstract

The strong sea surface reflectivity causes source- and receiver-ghost notches: areas in the wavenumber-frequency domain where the signal is very weak. If the subsurface is complex, the source-ghost notch is most apparent in common detector gathers. It may even be absent in common source gathers, i.e., in shot records. For the detector-ghost notches it is the other way around: they are most apparent in shot records and may be absent in detector gathers. Both notch types show up in the common-offset and CMP domains albeit less clearly. In the case of a complex subsurface, the deghosting process should be carried out in the right domain: source deghosting in the common receiver domain, detector deghosting in the common shot domain. In the case of a simple subsurface, deghosting can be carried out in any domain.