Finite Element Method model for towed seismic streamer dynamics

Towed underwater seismic streamer cables are utilized extensively for marine petroleum exploration. A number of streamers of up to 12 km length containing seismic sensors are towed behind a vessel to investigate the sub-seabed strata. Up to 20 streamers could be towed with 25-100 meter separation between adjacent streamers. Streamer positioning is typically achieved by Kalman combining available observations with simplified streamer models. Presently, the intention is to provide an improved streamer model suited for implementation in Ensemble or Extended Kalman filters for streamer positioning purposes. For accurate positioning of the towed streamers, it is necessary to have a representative and sufficiently detailed physical model of the towed streamers. In the present study, a two-dimensional Finite Element Method (FEM) describing the dynamics of a towed cable is extended to include larger cable deflections as well as introduction of control bird forces. Sea current is included and could vary along the streamer. Further, tension modeling including tailbuoy drag is implemented. The present implementation is validated against a proprietary seismic streamer simulator as well as full-scale data from a seismic survey.