System and method for wireless data collection from seismic recording buoys

• US 20070091722A1
• Filed: 10/20/2005
• Published: 04/26/2007
• Est. Priority Date: 10/20/2005
• Status: Active Grant

• Current Assignee: PGS Geophysical As (PGS ASA)
• Original Assignee: PGS Geophysical As (PGS ASA)
• Inventors: Karlsen, Kenneth
• Granted Patent: US 7,466,627 B2
• Time in Patent Office: Days
• US Class Current: 367/76
• CPC Class Codes: G01V 1/223 Radioseismic systems
• CPC Class Codes: H01Q 3/06 over a restricted angle
• CPC Class Codes: H01Q 3/36 with variable phase-shifters

Abstract

A seismic data acquisition telemetry system includes a seismic vessel including a data recording system thereon. The system includes a seismic data gathering unit in operative connection with at least one seismic sensor. The system includes a first antenna disposed on the seismic vessel and a second antenna disposed on the data gathering unit, at least one of said first and second antennas being directional. Means are included for orienting a sensitive direction of the directionally sensitive antenna toward the other of said first and second antennas.

Claims

1. A seismic data acquisition system, comprising:

a seismic vessel;

a seismic data gathering unit in operative connection with at least one seismic sensor;

a first antenna disposed on the seismic vessel and a second antenna disposed on the data gathering unit, at least one of said first and second antennas being directionally sensitive; and

means for orienting a sensitive direction of the directionally sensitive antenna toward the other of said first and second antennas.

2. The system of claim 1 wherein the means for orienting a sensitive direction of the directionally sensitive antenna comprises means for determining a geodetic direction from the directionally sensitive antenna to the other of said first and second antennas, and means for rotating the sensitive direction substantially to the geodetic direction.

3. The system of claim 2 wherein the directionally sensitive antenna comprises a rotatably mounted parabolic reflector, and the means for rotating comprises a motor rotationally coupled to the reflector.

4. The system of claim 3 further comprising a directional sensor coupled to the reflector, and wherein the means for rotating comprises means for comparing a direction measured by the directional sensor to the determined geodetic direction.

5. The system of claim 4 wherein the directional sensor comprises a two channel magnetometer.

6. The system of claim 2 wherein the means for determining geodetic direction comprises a first global positioning system receiver disposed near the first antenna on the seismic vessel and a second global positioning system receiver disposed near the second antenna on the seismic data gathering unit, and a telemetry transmitter for communicating position information to the global positioning system receiver near the directionally sensitive antenna from the other of the global positioning system receivers.

7. The system of claim 2 wherein the directionally sensitive antenna comprises a plurality of dipole antennas each coupled to a respective output of a phase shifter, and the means for rotating comprises means for determining a phase shift to be applied to each dipole antenna such that a combined sensitivity of said dipole antennas has a direction corresponding to the geodetic direction, the means for determining phase shift being operatively coupled to the phase shifter.

8. The system of claim 2 wherein the means for orienting comprises a signal amplitude detector operatively coupled to the means for rotating, and the means for rotating comprises means for stopping rotation when a detected telemetry signal amplitude reaches a maximum value.

9. The system of claim 8 wherein the directionally sensitive antenna comprises a parabolic reflector, and the means for rotating comprises a motor rotationally coupled to the reflector.

10. The system of claim 8 wherein the directionally sensitive antenna comprises a plurality of dipole antennas each coupled to a respective output of a phase shifter, and the means for rotating comprises means for determining a phase shift to be applied to each antenna such that a combined sensitivity of the dipole antennas has a direction corresponding to a direction of maximum telemetry signal amplitude, the means for determining phase shift being operatively coupled to the phase shifter.

11. The system of claim 1 wherein the seismic sensor is disposed in an ocean bottom cable.

12. A method for maintaining data telemetry between a seismic data gathering unit and a seismic vessel, comprising:

sensing a direction between the seismic vessel and the data gathering unit; and

orienting a directionally sensitive antenna substantially along the direction.

13. The method of claim 12 wherein sensing a direction comprises determining a geodetic position of the seismic vessel and of the data gathering unit, and calculating the direction from the geodetic positions.

14. The method of claim 13 wherein the orienting comprises physically rotating the antenna such that the sensitive direction of the antenna is substantially along the geodetic direction.

15. The method of claim 13 wherein the orienting comprises electronically rotating a sensitive direction of the antenna to substantially be along the geodetic direction.

16. The method of claim 12 wherein the sensing and orienting comprise measuring a detected telemetry signal amplitude, and rotating a sensitive direction of the antenna until the detected telemetry signal amplitude reaches a maximum value.

17. A method for conducting a marine seismic data acquisition, comprising:

deploying at least one ocean bottom cable on a bottom of a body of water, the ocean bottom cable having a plurality of seismic sensors thereon at spaced apart locations;

towing a seismic energy source from a seismic vessel near the surface of the body of water, and actuating the source at selected times;

detecting seismic signals at the sensors, and communicating the detected signals to a data gathering unit;

determining a direction between the seismic vessel and the data gathering unit;

orienting a directionally sensitive antenna substantially along the direction; and

telemetering the communicated signals from the gathering unit to the seismic vessel through the antenna.

18. The method of claim 17 wherein the determining a direction comprises determining a geodetic position of the seismic vessel and the data gathering unit.

19. The method of claim 18 wherein the orienting comprises physically rotating the antenna such that the sensitive direction of the antenna is substantially along the geodetic direction.

20. The method of claim 18 wherein the orienting comprises electronically rotating a sensitive direction of the antenna to substantially be along the geodetic direction.

21. The method of claim 17 wherein the determining direction and orienting comprise measuring a detected telemetry signal amplitude, and rotating a sensitive direction of the antenna until the detected telemetry signal amplitude reaches a maximum value.

22. The method of claim 21 wherein the orienting comprises physically rotating the antenna such that the sensitive direction of the antenna is substantially along the geodetic direction.

23. The method of claim 21 wherein the orienting comprises electronically rotating a sensitive direction of the antenna to substantially be along the geodetic direction.

24. The method of claim 17 wherein the antenna is disposed on the data gathering unit.

25. The method of claim 17 wherein the antenna is disposed on the seismic vessel.