Marine broadband case study offshore China

Dual tow-depth acquisition configurations are used to mitigate the band-limiting effect of the sea-surface ghost in marine streamer surveys. Here we report on the analysis of a 2D broadband marine seismic project acquired offshore China. The deployment configuration included over/under sources and three streamers towed at different depths (5, 17, and 23 m). This configuration allowed not only for analysis of dual tow depth as a method for increasing bandwidth, but also for evaluation of two distinct dual tow-depth combinations, over/under and sparse-under. The project provided the first opportunity to make this comparison. Evaluation of reflection images, filter panels, amplitude spectra, and signal/noise separations demonstrates that both techniques are effective at compensating for the filtering effect of the ghost response, but also suggest that the improved results from each dual tow-depth technique are very comparable. Given the operational advantages of the sparse-under technique, due to the reduced streamer requirements, we conclude that the sparse-under technique is an attractive option for 3D deployments.