Variable buoyancy control and recovery system for seismic data acquisition

Patent metadata

Field	Value
Publication number	US-10191171-B2
Application number	US-201715443546-A
Country	US
Kind code	B2
Filing date	Feb 27, 2017
Priority date	Feb 26, 2016
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A seismic apparatus includes one or more seismic cable systems configured to acquire seismic data, each seismic cable system having one or more of a cable jacket, a reservoir for a ballast fluid or other ballast medium, and an actuator or other transfer mechanism configured to transfer the ballast fluid between the reservoir and the seismic cable system during acquisition of the seismic data, e.g., where the ballast fluid is transferred to the seismic cable system within the cable jacket. A controller can be configured to adjust a buoyancy of the seismic cable system responsive to the transfer of the ballast fluid, e.g., where the internal volume expands or contract based on the fluid transfer.

First claim

The invention claimed is:

1. An apparatus comprising:
a seismic cable system configured to acquire seismic data, the seismic cable system having a cable jacket;
a reservoir for ballast fluid;
a transfer mechanism configured to transfer the ballast fluid between the reservoir and the seismic cable system during acquisition of the seismic data, wherein the ballast fluid is transferred to the seismic cable system within the cable jacket;
a controller configured to adjust a buoyancy of the seismic cable system responsive to the transfer of the ballast fluid;
a modular housing disposed about the reservoir and the fluid transfer mechanism, wherein the modular housing is configured for mounting coaxially along the seismic cable system, wherein the modular housing is configured for coupling about the outer jacket of the seismic cable system; and
a port configured for transferring the ballast fluid from the reservoir through an outer diameter of the cable jacket.

2. The apparatus of claim 1 , wherein the buoyancy of the seismic cable system is responsive to expansion of the cable jacket upon transfer of the ballast fluid from the reservoir.

3. The apparatus of claim 1 , wherein the fluid transfer mechanism is configured to selectively transfer the ballast fluid along a length of the seismic cable system and the buoyancy is responsive to changes in a cross-sectional area of the cable jacket along the length.

4. The apparatus of claim 1 , wherein the controller is configured to trim the buoyancy along a length of the seismic cable system by selectively transferring the ballast fluid during acquisition of the seismic data.

5. The apparatus of claim 1 , wherein the transfer mechanism comprises a pump or valve configured to transfer the ballast fluid between the reservoir and a volume defined within an outer diameter of the cable jacket.

6. The apparatus of claim 1 , wherein the ballast fluid is selected to match an acoustic impedance of the cable jacket.

7. The apparatus of claim 1 , further comprising an external water column pressure sensor responsive to depth of the seismic cable system in the external water column proximate the pressure sensor, wherein the reservoir comprises a pressure vessel configured to release the ballast fluid into a volume defined within the cable jacket responsive to the depth.

8. The apparatus of claim 1 , further comprising first and second axial couplings configured for connecting the modular housing in-line between first and second adjacent sections of the seismic cable system, and further comprising an electronics module configured for data communication between the adjacent sections during acquisition of the seismic data.

9. The apparatus of claim 8 , further comprising an axial fluid coupling configured for transferring the ballast fluid from the reservoir into one or more of the adjacent sections seismic cable system, within an outer diameter of the cable jacket.

10. A ballast module comprising:
a housing adapted for mounting the ballast module along a seismic cable system configured for acquiring seismic data;
a reservoir disposed within the housing, the reservoir configured to transfer a ballast medium between the reservoir and a volume defined within an outer jacket of the seismic cable system, wherein the housing is configured for coupling the ballast module about the outer jacket of the seismic cable system;
a transfer mechanism configured to transfer the ballast medium through a port in the outer jacket; and
a controller configured to selectively operate the reservoir to control buoyancy of the seismic cable system, wherein the buoyancy is responsive to changes in the volume based on the transfer of the ballast medium during acquisition of the seismic data by the seismic cable system.

11. The ballast module of claim 10 , wherein the housing is configured for mounting coaxially along the seismic cable system between adjacent sections thereof, and further comprising a transfer mechanism configured to transfer the ballast medium into a core of one or more of the adjacent sections, within the volume defined within the outer jacket.

12. The ballast module of claim 10 , further comprising an interface configured for communications between the controller and an eternal trim control processor, wherein the controller is configured to selectively operate the reservoir to provide real-time buoyancy and trim control along a length of the seismic cable system in response to the communications, during acquisition of the seismic data.

13. The ballast module of claim 10 , further comprising a pressure sensor in communication with a water column external to the housing, wherein the pressure sensor is responsive to depth in the water column and the controller is configured to selectively operate the reservoir based on the depth.

14. A seismic data acquisition system comprising:
one or more seismic cables configured for acquiring seismic data;
one or more ballast modules disposed along each of the seismic cables, each of the ballast modules comprising:
a housing configured for mounting the ballast module between adjacent sections of the respective seismic cable, wherein the housing is configured to couple the ballast module about an outer jacket of the respective seismic cable;
a reservoir disposed within the housing, the reservoir containing a ballast fluid, wherein the reservoir is configured to transfer the ballast fluid between the reservoir and the respective seismic cable; and
a transfer mechanism coupled to the reservoir, the transfer mechanism configured to transfer the ballast fluid between the reservoir and a volume defined within the outer jacket of the respective seismic cable, through a port in the outer jacket;

wherein buoyancy along a length of each of the seismic cables is controlled by changes in the volume defined within the respective cable jacket, responsive to the transfer of the ballast fluid.

15. The system of claim 14 , further comprising a processor in communication with the one or more ballast modules disposed on one of the seismic cables, the processor configured to trim the buoyancy of the respective seismic cable along the respective length thereof, wherein the buoyancy is responsive to the transfer of the ballast fluid between the respective ballast modules and the volume defined within the inner jacket of the respective seismic cable, as determined by the processor.

16. The system of claim 15 , further comprising one or more interfaces configured for peer-to-peer communication of a recovery signal among the one or more ballast modules disposed along the one or more seismic cables, whereby each of the ballast modules is configured to transfer the ballast fluid to provide positive buoyancy to an adjacent section of the respective seismic cable in response to the recovery signal.

17. The system of claim 15 , further comprising a port defined in each reservoir, the port configured for one or both of replenishing the ballast fluid or extracting the ballast fluid to an external vessel disposed outside the respective housing.

18. A method comprising:
deploying a seismic cable to a seismic medium;
acquiring seismic data with the seismic cable;
operating a transfer mechanism of a ballast module to transfer a ballast medium between a reservoir and a volume defined in a cable jacket of one or more adjacent sections of the seismic cable via a port defined in the cable jacket, wherein the reservoir is disposed within a housing configured for mounting the ballast module about the cable jacket between the adjacent sectio

Assignees

• Ion Geophysical Corp

Inventors

• Olivier André W

Classifications

• G01V1/20 Primary

  Arrangements of receiving elements, e.g. geophone pattern · CPC title

• B63G8/42

  Towed underwater vessels · CPC title

• G01V2001/207

  Buoyancy · CPC title

• G01V1/38

  specially adapted for water-covered areas (G01V1/28 takes precedence) · CPC title

• G01V1/3808

  Seismic data acquisition, e.g. survey design · CPC title