Efficient front-end & streamer spread dynamic model

For marine seismic surveys, multiple streamers are towed behind a vessel. Sources firing at each shotpoint provide sound signals, which after seabed reflection are received by numerous hydrophones located at the streamers. Processing the received signals gives the basis for mapping the local seabed structure. Typically, surveys are run line-by-line, requiring a 180° turn between lines. This line-change operation is time consuming and could result in equipment strain and operational risks. Modeling the in-sea hardware gives the basis for designing improved line-change maneuvers and including operational factors such as projected sea current, and for improved streamer steering methods such as Target Point Streamer Steering (TPSS). The present study describes a dynamic 2D model for the major in-sea hardware of a seismic survey including streamers and front-end. The streamers include tailbuoys and lateral steering devices. The front-end model is comprised of lead-in and wide tow cables, deflectors, spread ropes and spur-lines. The model is a co-simulation, where each cable line is modeled using a finite difference method. The computational cost of the model is low. The model is validated against survey data from two 1.5-hour line-change runs showing reasonable accuracy. The validated cases feature a spread containing 12 streamers of 4.2 km length each. Streamer steering and sea current data are included in the validation.