Methods and apparatus for node positioning during seismic survey
AssigneePGS Geophysical AS
InventorMichael B. Erneland
Life of this patent
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Abstract
Disclosed are apparatus and methods acoustic node positioning during a marine survey. In one embodiment, positions of a plurality of nodes are calibrated using acoustic transceivers. In addition, changes in the positions of the nodes are tracked using accelerometers. In another embodiment, a traveling wave is detected, and an effect of the traveling wave is projected on steering devices in a projected path of the traveling wave. Time-dependent control signals are computed and applied to the steering devices to maintain a local streamer geometry. Other embodiments, aspects, and features are also disclosed.
Claims21
A method performed during a marine seismic survey, the method comprising:
- towing a plurality of nodes in a body of water over a survey area;
- calibrating positions of the plurality of nodes using acoustic ranging signals between acoustic transceivers at the nodes;
- and
- tracking changes in positions of the plurality of nodes using accelerometers,
- wherein the positions of the nodes are calibrated at acoustic calibration intervals and are tracked at a series of times between the acoustic calibration intervals.
An apparatus for marine seismic surveying, the apparatus comprising:
- a plurality of acoustic transceivers configured to be towed by a vessel in a body of water;
- a plurality of accelerometers configured to be towed by the vessel in the body of water;
- and
- a control apparatus communicatively coupled to the acoustic transceivers and the accelerometers, wherein the control apparatus is configured to calibrate positions of the acoustic transceivers and track changes in positions of the accelerometers, wherein the control apparatus is further configured to track the positions of the accelerometers at a series of times from a preceding acoustic calibration time to a next acoustic calibration time.
A method of maintaining a spread of nodes during a marine seismic survey, the method comprising:
- towing the nodes on multiple streamers that are spaced apart;
- detecting a traveling wave which accelerates a subset of the nodes;
- projecting an effect of the traveling wave on a subset of steering devices on the multiple streamers, the subset of steering devices being in a projected path of the traveling wave, by extrapolating motion of the traveling wave over time to predict a future effect of the traveling wave on the subset of steering devices;
- computing time-dependent control signals to be applied at the subset of steering devices to counter the projected effect of the traveling wave;
- and
- applying the time-dependent control signals to the subset of steering devices to maintain a local streamer geometry.
Dependencies are inferred from the claim text.