Abstract: The invention relates to a seismic streamer (1) for underwater towing at a towing speed in ice-free or wholly or partially icy water, the streamer (1) is provided with birds (2) spaced along the streamer, the streamer including the birds (2) has negative buoyancy, the birds have wings (8) which can be set so that the birds during movement in the water apply an upward or downward force on the streamer. The streamer (1) is provided with buoyant bodies (4) spaced along the streamer, the buoyant bodies are connected to the streamer by spacer elements (5), the streamer including the birds, the buoyant bodies with associated spacer elements and any other equipment together have positive buoyancy. The invention also relates to a corresponding method for securing a seismic streamer (1) from damage at a substantial reduction or cessation of towing speed when towing underwater in ice-free or wholly or partially icy water.

Abstract: A coating (100) for a marine seismic streamer with several streamer sections (110, 130) connected by connectors (120), wherein the coating (100) is a sheet comprising a substrate (101) for containing an antifouling agent. The coating (100) is cut into a strip, e.g. a tape (104) with an adhesive layer, which may be wrapped around a streamer connector (120), where barnacles and other marine organisms thrive.

Abstract: A positioning system (100) for marine seismic surveying, comprising a towing vessel (110), a source array (120) and a receiver array (130) with several streamers (131). Each streamer (131) comprises at least three birds (134) and positioning sensors (134-137) wherein several seismic receivers (132) are placed between each pair of birds (134). The system (100) comprises a dynamic model wherein each streamer (131) is represented by a fitted B-spline curve and each bird (134) is associated with a constant velocity and a constant acceleration; and a Kalman filter using the dynamic model and observations from the positioning sensors (134-137) to provide a geodetic position of each seismic receiver (132) with better accuracy than the dynamic model alone and observations alone within a time interval ?t equal to or less than a minimum time between shots determined by the source array (120).

Abstract: The invention provides a system (100) for marine seismic surveying, comprising a towing vessel (110) with a controller, a source array (120) and a receiver array (130) with several streamers (131). The source array (120) comprises n>4 identical subarrays (121) configured as at least (n?1) seismic sources S1, . . . , Sn-1, wherein adjacent subarrays (121) are part of at least two sources Si, Sj at different times.

Abstract: A cable fairing (fairing) (40) for reducing the flow resistance for a cable (45) has a wing formed cross section with a wide, rounded front and a tapered tail, a through-going cable channel (46) for the cable (45) perpendicular to the cross section of the widest part of the cross section. The wing profile comprises an elastic material of sufficient stiffness to maintain the shape when it is towed thereby causing flow resistance. The cable fairing (40) has slots (42) cut into the elastic material from the tail towards the cable channel (46), so that the tail comprises slats (41) which can be bent parallel to the cable channel (46) to reduce the cross-section of the cable fairing. By this is low flow resistance, as from a stiff cable jacket, combined with sufficient elastic deformability so the cable (45) with attached cable fairings (40), can be winched and pass through narrow openings in the deployment and retrieval, and wound onto a reel for storage and transport.

Abstract: A seismic data acquisition system comprising a composite marine seismic cable and a winch, the composite marine seismic cable comprising a sensor cable and a lead-in cable for providing electrical connections to the sensor cable, and the winch comprising a first cable compartment for the lead-in cable and a second cable compartment for the sensor cable, wherein the lead-in cable and the sensor cable may be deployed or recovered independently of each other. There is also a method of deploying a composite seismic cable comprising a lead-in cable and a sensor cable.