Ocean bottom seismometer package

• US 8,879,362 B2
• Filed: 08/02/2012
• Issued: 11/04/2014
• Est. Priority Date: 05/30/2003
• Status: Expired due to Term

• Current Assignee: Magseis FF, LLC
• Original Assignee: Fairfield Industries Incorporated
• Inventors: Ray, Clifford H., Fisseler, Glenn D., Thompson, James N., Haygood, Hal B.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US13/565,445
• Publication Number:
  US 20120294122A1
• Time in Patent Office: 824 Days
• Field of Search: 367/178, 367/188, 367/122
• US Class Current: 367/178
• CPC Class Codes: G01V 1/166 Arrangements for coupling receivers to the ground
• CPC Class Codes: G01V 1/18 Receiving elements, e.g. seismometer, geophone or torque detectors, for localised single point measurements
• CPC Class Codes: G01V 1/247 Digital recording of seismic data, e.g. in acquisition units or nodes
• CPC Class Codes: G01V 1/38 specially adapted for water-covered areas G01V1/28 takes precedence
• CPC Class Codes: G01V 1/3808 Seismic data acquisition, e.g. survey design
• CPC Class Codes: G01V 1/3852 to the seabed
• CPC Class Codes: G01V 2210/1427 Sea bed
• CPC Class Codes: Y10T 24/39 Cord and rope holders

Abstract

A marine seismic exploration method and system comprised of continuous recording, self-contained ocean bottom pods characterized by low profile casings. An external bumper is provided to promote ocean bottom coupling and prevent fishing net entrapment. Pods are tethered together with flexible, non-rigid, non-conducting cable used to control pod deployment. Pods are deployed and retrieved from a boat deck configured to have a storage system and a handling system to attach pods to cable on-the-fly. The storage system is a juke box configuration of slots wherein individual pods are randomly stored in the slots to permit data extraction, charging, testing and synchronizing without opening the pods. A pod may include an inertial navigation system to determine ocean floor location and a rubidium clock for timing. The system includes mathematical gimballing. The cable may include shear couplings designed to automatically shear apart if a certain level of cable tension is reached.

Claims

1. An ocean bottom seismic data collection system comprising:

a low-profile, disk-shaped case comprising a plate and a wall coupled to the plate;

at least one geophone disposed within the case;

a clock disposed within the case;

a power source disposed within the case; and

a seismic data recorder disposed within the case,

wherein the system is configured to have a negative buoyancy.

2. The ocean bottom seismic data collection system of claim 1, further comprising an internal, water-tight compartment in which the seismic data recorder is disposed.

3. The ocean bottom seismic data collection system of claim 1, further comprising an internal, water-tight compartment in which the geophone is disposed.

4. The ocean bottom seismic data collection system of claim 1, further comprising an internal, water-tight compartment in which the clock is disposed.

5. The ocean bottom seismic data collection system of claim 1, further comprising an internal, water-tight compartment in which the power source is disposed.

6. The ocean bottom seismic data collection system of claim 1, wherein a diameter of the case is greater than a height of the case.

7. The ocean bottom seismic data collection system of claim 1, wherein the plate is configured to couple to an ocean bottom such that a seismic wave can pass through the plate to the geophone.

8. The ocean bottom seismic data collection system of claim 1, wherein the case further comprises a second plate.

9. The ocean bottom seismic data collection system of claim 8, wherein at least one of the plate or the second plate is configured to couple to an ocean bottom such that a seismic wave can pass through at least one of the plate or the second plate to the geophone.

10. The ocean bottom seismic data collection system of claim 8, wherein the wall is further coupled to the second plate.

11. The ocean bottom seismic data collection system of claim 8, wherein at least one of the plate, the second plate or the wall are a substantially circular.

12. An ocean bottom seismic unit comprising:

disk-shaped case comprising a plate and a wall coupled to the plate;

at least one geophone disposed within the case;

a clock disposed within the case;

a power source disposed within the case; and

a seismic data recorder disposed within the case,

wherein the system is configured to have a negative buoyancy.

13. The ocean bottom seismic unit of claim 12, wherein the disk-shaped case is a low-profile case having a diameter greater than a height of the case.

14. The ocean bottom seismic data collection system of claim 12, further comprising an internal, water-tight compartment in which the seismic data recorder is disposed.

15. The ocean bottom seismic data collection system of claim 12, further comprising an internal, water-tight compartment in which the geophone is disposed.

16. The ocean bottom seismic data collection system of claim 12, further comprising an internal, water-tight compartment in which the clock is disposed.

17. The ocean bottom seismic data collection system of claim 12, further comprising an internal, water-tight compartment in which the power source is disposed.

18. A method of deploying ocean bottom seismic units comprising:

deploying, via a cable engine from a cable container, a first portion of cable below a surface of water;

positioning an ocean bottom seismic unit adjacent a second portion of the cable above the surface of the water, the ocean bottom seismic unit including;

a disk-shaped case comprising a plate and a wall coupled to the plate;

at least one geophone disposed within the case;

a clock disposed within the case;

a power source disposed within the case; and

a seismic data recorder disposed within the case;

coupling, via a coupling mechanism, the ocean bottom seismic unit at the second portion of the cable;

deploying the ocean bottom seismic unit into the water via the cable; and

controlling a movement of the ocean bottom seismic unit to position the ocean bottom seismic unit on the seabed.

19. The method of claim 18, wherein the coupling mechanism comprises a sleeve, the method further comprising:

coupling the sleeve to the second portion of the cable; and

coupling the ocean bottom seismic unit to the sleeve.

20. The method of claim 19, further comprising:

fixedly coupling the sleeve to the second portion of the cable using one or more pins.

21. The method of claim 19, further comprising:

coupling the sleeve to the second portion of the cable such that the sleeve slides on the cable.

22. The method of claim 19, further comprising:

sliding the sleeve from the second portion of the cable to a third portion of the cable below the surface of the water.

23. The method of claim 19, wherein coupling the sleeve to the cable comprises:

placing the cable in an axial bore of the sleeve.

24. The method of claim 19, wherein the coupling mechanism further comprises a clamp, the method further comprising:

using the clamp to couple the sleeve to the second portion of the cable.

25. The method of claim 19, further comprising:

inserting a pin through the sleeve and the second portion of the cable to secure the sleeve from sliding.

26. The method of claim 19, further comprising:

inserting a plurality of pins through the sleeve and the cable in planes substantially perpendicular to an axis of the cable to secure the sleeve to the cable.

27. The method of claim 18, wherein the coupling mechanism comprises a latching mechanism, the method further comprising:

latching, via the latching mechanism, the ocean bottom seismic unit to the cable.

28. The method of claim 27, further comprising:

closing the latching mechanism to latch the ocean bottom seismic unit to the cable.

29. The method of claim 27, further comprising:

opening the latching mechanism to unlatch the ocean bottom seismic unit from the cable.

30. The method of claim 27, wherein the latching mechanism is attached to a portion of the ocean bottom seismic unit.

31. The method of claim 27, wherein the latching mechanism is attached to a portion of the ocean bottom seismic unit to cause a major axis of the latching mechanism to be substantially non-intersecting with a z-axis of the ocean bottom seismic unit.

32. The method of claim 27, further comprising:

closing the latching mechanism at the second portion of the cable; and

opening the latching mechanism at a third portion of the cable below the surface of the water.

33. The method of claim 32, wherein the first portion is different from the third portion.

34. The method of claim 27, further comprising:

sliding, via the latching mechanism, the ocean bottom seismic unit from the second portion of the cable to a third portion of the cable below the surface of the water.

35. The method of claim 27, wherein the ocean bottom seismic units have a greater negative buoyancy than the cable, the method further comprising:

slowing, by the cable, a descent of the ocean bottom units through the water.