Benefits of multi-sensor streamers for broadband acquisition
Jo Firth, Gordon Poole, Federico Buriola, Steve McDonald, Paul Fallon, Steve Hollingworth, James Cooper and Gaeton Mellier
Journal name: First Break
Issue: Vol 36, No 11, November 2018 pp. 65 - 69
Info: Article, PDF ( 4.78Mb )
Price: € 30
Broadband towed-streamer data has extended the usable seismic bandwidth at both ends of the frequency spectrum. As well as enriching the overall seismic image, improved low frequencies have delivered more reliable full-waveform inversion results and more quantitative elastic inversion, while improved high frequencies enable better interpretation of thin-layered structures. Various strategies have been developed to acquire broadband data, ranging from processing-only approaches using horizontal-tow hydrophone-only streamers, to combined acquisition and processing schemes using multi-level streamers (Posthumus, 1993), variable-depth streamers (Soubaras, 2010) or multi-sensor streamers (Carlson et al., 2007). The desire to extend all the benefits of broadband 3D data to 4D time-lapse surveys has been constrained by the requirement for repeatability between successive surveys. The use of deeptowed multi-sensor streamers in time-lapse acquisition creates challenges, as the existing baseline surveys will often have been acquired using a shallow-tow streamer. For optimal 4D repeatability, subsequent monitor acquisitions would traditionally be acquired using the same streamer depth as the earlier surveys. Using a case study from the North Sea, we tested recording monitor data at a deeper streamer depth than the baseline survey using multi-sensor streamers, and then redatuming to simulate data recorded at the shallow streamer depth. Based on the successful outcome of this trial, we successfully acquired two 4D monitor surveys during the recent summer season using this method.