System for depth control of a marine deflector
AssigneeWesternGeco L.L.C.
InventorsRune Toennessen, Emmanuel Keskes, Eskild Storteig, Per Helgerud, Vahid Moosavi, Philippe Saint-Pere
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Abstract
A system for adjusting a deflector in a seismic survey comprises a generally upright deflector body and at least one bridle connected to a seismic cable. The bridle includes an upper segment secured to an upper connection point on the deflector body, and a lower segment coupled to a lower connection point on the deflector body. The upper bridle segment, lower bridle segment and deflector body define a geometry between themselves. This geometry is adjustable by at least one actuator so as to control the tilt angle of the deflector body.
Claims57
A system, comprising:
- a deflector body disposed inside a body of water characterized by a tilt angle relative to vertical, wherein the tilt angle controls a depth in which the deflector body is disposed inside the body of water;
- a bridle connected to a seismic cable, the bridle having a first upper segment secured to a first upper connection point on the deflector body and a first lower segment secured to a first lower connection point on the deflector body, wherein a length of the first upper segment and a length of the first lower segment is used to define a ratio, and wherein the first upper segment, the first lower segment and the deflector body form a geometry and the geometry is manipulated when the ratio is adjusted;
- and
- an actuator coupled to the bridle, wherein the actuator is configured to adjust the ratio of the length of the first upper segment to the length of the first lower segment to vary the tilt angle of the deflector body, thereby controlling the depth of the deflector body as the deflector body is being towed inside the body of water by the vessel.
A method for controlling a depth of a deflector under tow, comprising:
- coupling a deflector to a bridle;
- coupling the bridle to a towing cable;
- coupling the towing cable to a vessel;
- coupling a first segment of the bridle to a first upper rotatable towpoint on the deflector;
- coupling a second segment of the bridle to a first lower rotatable towpoint on the deflector;
- towing the deflector behind the vessel, thereby forming a tilt angle between the deflector and a vertical;
- and
- adjusting the ratio of the length of the first segment to the length of the second segment to vary the tilt angle between the deflector and the vertical using the first upper rotatable towpoint and the first lower rotatable towpoint, thereby controlling the depth of the deflector inside a body of water as the deflector is being towed behind the vessel, wherein the first segment, the second segment and the deflector form a geometry and the geometry is manipulated when the ratio is adjusted.
Dependencies are inferred from the claim text.