Positioning along a streamer using surface references
AssigneeCgg Services SAS
InventorLaurent DOLLON
Life of this patent
Estimating the term…
Abstract
Positioning along a towed streamer is enhanced by using acoustic signals emitted from a surface vehicle that is not physically linked to the survey equipment. The surface vehicle navigates to remain above a target location between the streamer's head and its tail in the towing direction. The positions of acoustic units placed underwater along the streamer or on an adjacent streamer are determined using the acoustic signals emitted by the surface vehicle.
Claims20
A method for positioning along a streamer, the method comprising:
- detecting an acoustic signal emitted from a surface vehicle, at a known position between a head of a streamer and a tail of the streamer in a towing direction, the acoustic signal being detected by at least one among acoustic units placed at different locations along the streamer;
- and
- evaluating positions of the acoustic units using the acoustic signal,
- wherein the surface vehicle is not tied to any piece of survey equipment.
A surface vehicle, ASV, usable during seismic surveys for positioning along a streamer, the surface vehicle comprising:
- a navigation and propulsion system configured to maintain the surface vehicle substantially above a target location between a head of the streamer and a tail of the streamer;
- a positioning system configured to determine surface vehicle's position;
- and
- an underwater acoustic source configured to emit acoustic signals to be detected by acoustic units placed along the towed streamer in a towing direction, thereby enabling evaluation of positions of the acoustic units using the acoustic signals,
- wherein the surface vehicle is not tied to any piece of survey equipment.
An acoustic unit attached to a streamer towed during a marine seismic survey, the acoustic unit comprising:
- a receiver configured to receive acoustic signals;
- a transmitter configured to retransmit the acoustic signals to adjacent acoustic units;
- and
- a processor configured to estimate positions of the acoustic unit using the acoustic signals emitted by a surface vehicle that navigates to be substantially above a target location between a head of the streamer and a tail of the streamer in a towing direction, and is not tied to any piece of survey equipment.
Dependencies are inferred from the claim text.