Optical methods and systems in marine seismic surveying

• US 7,835,221 B2
• Filed: 07/06/2006
• Issued: 11/16/2010
• Est. Priority Date: 07/06/2006
• Status: Expired due to Fees

• Current Assignee: WesternGeco LLC
• Original Assignee: WesternGeco LLC
• Inventors: Vigen, Erik, Yang, Luren
• Primary Examiner(s): Keith; Jack
• Assistant Examiner(s): BREIER, KRYSTINE E
• Application Number:
  US11/456,059
• Publication Number:
  US 20080008031A1
• Time in Patent Office: 1,594 Days
• Field of Search: 367/58, 367/106, 367 15- 19
• US Class Current: 367/19
• CPC Class Codes: G01V 1/3835 measuring position, e.g. by GPS or acoustically

Abstract

Methods and systems for determining position of marine seismic spread components are disclosed. One method comprises exposing an underwater marine seismic spread component to an optical device, and calculating geometry of the spread component using at least some of the data obtained by the optical device, for example travel time for an optical signal to travel to and return from one or more spread elements in the spread component. The optical device may comprise one or more laser scanners, cameras, or laser scanners and cameras. The spread component may be a marine seismic source, a marine seismic streamer cable, and the like. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. A method comprising:

exposing a seismic source to an optical signal from a laser positioned near a center of the seismic source;

reflecting a portion of the optical signal by one or more reflectors disposed on two or more spread elements of the seismic source;

calculating a geometry of the seismic source by using travel time for the optical signal to travel to and return from the two or more spread elements; and

producing a network of optical ranges, wherein each end of the network of optical ranges corresponds to reflectors.

2. The method of claim 1 wherein each reflector is 1) an optical reflector attached directly on the two or more spread elements;

2) an optical reflector integrated into the two or more spread elements;

     3) an optically reflective surface or portion of a surface of the two or more spread elements;

or combinations thereof, wherein the optical reflector is selected from a prism, a mirror, a reflective tape, reflective signage, reflective symbols, and combinations thereof.

3. The method of claim 1 wherein the optical signal is selected from continuous and discontinuous signals.

4. The method of claim 1 comprising identifying a reflection point as being a target point of interest, extracting a range measurement for use in a computing an optical network, and filtering out less useful range data before computing the optical network.

5. The method of claim 2 comprising adjusting optical signal beam size and/or reflector size to compensate for dispersion of the optical signal.

6. The method of claim 1 wherein the calculating geometry occurs virtually continuously and uses one or more algorithms stored on a computer.

7. The method of claim 1 comprising measuring position and three-dimensional attitude of any spread component using a positioning system selected from an acoustic positioning system, a satellite positioning system, an inertial platform, and combinations thereof.

8. The method of claim 1 wherein the calculating geometry comprises using a computer selected from a vessel-located on-board computer, a remote computer, and both.

9. The method of claim 1 wherein the seismic source has dimensions selected from one dimension, two dimensions, and three dimensions, and wherein one or more additional geometric measures are used to calculate size of the seismic source.

10. The method of claim 1, wherein calculating the geometry of the seismic source comprises determining one or more distances between the two or more spread elements using the travel time for the optical signal to travel to and return from the two or more spread elements.

11. The method of claim 1, wherein the optical signal is emitted through water.

12. The method of claim 1, wherein the laser is disposed under water.

13. The method of claim 1, wherein exposing the seismic source to the optical signal comprises:

directing the optical signal at one or more mirrors; and

rotating the one or more mirrors such that the optical signal is sent in one or more directions.

14. A system comprising:

at least one laser configured to expose a seismic source to an optical signal, the seismic source comprising two or more spread elements, wherein each of the two of the spread elements has an optical reflector, and wherein the at least one laser is positioned near a center of the seismic source; and

a calculation unit configured to;

receive data from the optical reflector;

use at least some of the data to calculate geometry of the seismic source; and

produce a network of optical ranges, wherein each end of the network of optical ranges corresponds to the optical reflector.

15. A method comprising:

exposing a plurality of underwater marine seismic sensors to an optical signal from one or more lasers positioned above or below the underwater marine seismic sensors, wherein the optical signal is emitted through at least two mirrors to project the optical signal in a plurality of directions, wherein the plurality of directions is shaped as a sphere;

reflecting at least a portion of the optical signal by a reflector disposed on each of the underwater marine seismic sensors; and

producing a network of optical ranges, wherein each end of the network of optical ranges corresponds to the reflector, wherein the network of optical ranges corresponds to the plurality of underwater marine seismic sensors.

16. A method comprising:

exposing a plurality of underwater marine seismic sources to an optical signal from one or more lasers positioned above or below the underwater marine seismic sources, wherein the optical signal directed at a rotating mirror and a prism to project the optical signal in a plurality of directions, wherein the plurality of directions is shaped as a sphere;

reflecting at least a portion of the optical signal by a reflector disposed on each of the underwater marine seismic sources; and

producing a network of optical ranges, wherein each end of the network of optical ranges corresponds to the reflector, wherein the network of optical ranges corresponds to the plurality of underwater marine seismic sources.