Estimating ocean currents from the shapes of laterally steered streamer arrays
Timothy Grant, Robert Laws and Emily Shuckburgh
Journal name: First Break
Issue: Vol 32, No 12, December 2014 pp. 57 - 66
Info: Article, PDF ( 5.01Mb )
When conducting marine seismic surveys, ocean currents noticeably perturb seismic streamers from their desired location. To accurately monitor a reservoir, the receivers in the streamers must be as close as possible to their previous positions. Therefore, it is desirable to know the currents in real time. Previous work has used the position and tension in a streamer to infer the currents. However, in many streamer systems, tension is not measured along the streamer. To overcome this problem, we propose that, by assuming that ocean currents are horizontally divergence-free, it should still be possible to reconstruct the currents from the positions of multiple streamers. Additionally, the previous work assumed that, when modelling a streamer, bending stiffness can be neglected. It is not clear that this assumption is correct when steering devices are attached; we therefore examine this assumption, using a novel finite difference scheme that incorporates bending stiffness, and conclude that it is safe to do so. Should such a method for inferring currents be implemented, the resulting information should not only be of value to the seismic industry, but also of use to oceanographers who wish to study submesoscale processes.