Deghosting

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Introduction

Ghost reflections in marine exploration are the main limiting factor of the recorded spectrum. The presence of discontinuity near the source and receiver creates secondary reflections that overlap the primary field, thus causing a reflection series that is much more populated than the true reflectivity. The presence of this discontinuity and thus the secondary reflections causes notches in the recorded wavefield spectrum.

History

With the advances in the Full Waveform Inversion (FWI), the lower part of the spectrum gained importance, which directed our attention back to the acquisition and processing methods of the marine recordings, with special emphasis on the low frequencies. Various recording and processing methods of such records (Jiao et.al, 1998) have been proposed and successfully utilized. Yilmaz et al (2015) introduced a recursive method of deghosting which runs the ghosting system in reverse to lift the effects of ghost reflections. Strictly speaking, the method is applicable in the tau-p domain but has been applied to x-t gathers with certain assumptions. Here we extend this method to x-t domain by making the recursive process time dependent, thus accounting for the variation of the arrival angles as a function of time. We will demonstrate the method on real marine recordings.


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Deghosting
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