Application of deghosting for spectral matching in OBS-streamer 4D processing

Relatively large spectral differences exist between streamer and ocean bottom seismometer (OBS) data, mostly due to their different ghost effects – streamer data have both shot- and receiver-side ghost, while OBS data only have shot-side ghost. In a recent OBS-streamer 4D study in deepwater Gulf of Mexico, we investigated three schemes of spectral matching between OBS and streamer data: conventional 1D matching of streamer to OBS, receiver deghosting on streamer data only, and full deghosting on both surveys. We find that receiver deghosting on streamer data is better than 1D matching, providing a better match between the streamer and OBS data before migration and an increased 4D signal-to-noise ratio (S/N) after migration. However, we also found that source deghosting on both surveys does not improve 4D results; instead the spectra of streamer and OBS, especially at lower frequencies, are more different after source deghosting. Receiver deghosting alone on the streamer data gives the best 4D results among the three spectral matching schemes.