Dynamically controlled foil systems and methods

Patent metadata

Field	Value
Publication number	US-2017106946-A1
Application number	US-201615295481-A
Country	US
Kind code	A1
Filing date	Oct 17, 2016
Priority date	Oct 15, 2015
Publication date	Apr 20, 2017
Grant date	—

Abstract

Foil systems for steering source and receiver arrangements for gathering seismic data are connected to buoys supporting seismic sources and receivers. Each foil system includes a positive buoyancy device, a pair of control cables, a plurality of foil sections, and an actuator. The pair of control cables may be attached to the buoyancy device and extend downward from the buoyancy device to a submerged end. The plurality of foil sections may be disposed along the control cables between the buoyancy device and the submerged end. The actuator may be configured to adjust attack angles of the foil sections by changing a tension in one or both of the control cables. Steering control is provided through a number of modes described by data distributed through a control system in communication with the foil systems.

First claim

What is claimed is:

1 . An apparatus comprising:
a positive buoyancy device; a pair of control cables attached to the buoyancy device and extending downward from the buoyancy device to a submerged end; a plurality of foil sections disposed along the control cables between the buoyancy device and the submerged end; and an actuator configured to adjust attack angles of the foil sections by changing a tension in one or both of the control cables.

2 . The apparatus of claim 1 , wherein the actuator is configured to change the tension by adjusting a length of one of the control cables.

3 . The apparatus of claim 2 , wherein the actuator is vertically disposed with respect to the control cables.

4 . The apparatus of claim 3 , wherein the actuator is mounted at least partially within the positive buoyancy device.

5 . The apparatus of claim 1 , wherein each of the foil sections defines a forward conduit adjacent to a leading edge of each foil section through which a first of the control cables extends and a rear conduit adjacent to a trailing edge of each foil section through which a second of the control cables extends.

6 . The apparatus of claim 5 , wherein the forward conduit and the rear conduit are spaced apart equidistantly apart in each of the plurality of foil sections.

7 . The apparatus of claim 5 , wherein the actuator is configured to adjust a length of the second control cable to thereby adjust the tension in the second control cable.

8 . The apparatus of claim 1 , wherein the pair of control cables are provided as a single cable that inflects at the submerged end to form the pair of control cables.

9 . The apparatus of claim 1 , wherein the submerged end is coupled to a cable configured to tow one or more seismic sources suspended from the positive buoyancy device.

10 . The apparatus of claim 1 , wherein the submerged end is coupled to a cable configured to tow a seismic streamer aft of the positive buoyancy device.

11 . The apparatus of claim 1 further comprising a controller disposed in the positive buoyancy device and in data communication with the actuator, wherein the controller is configured to direct the actuator to adjust the tension in one or both of the control cables and thereby regulate lift generated by the plurality of foil sections.

12 . The apparatus of claim 11 further comprising a navigational module in data communication with the controller, wherein the navigational module is configured to steer the positive buoyancy device based on the lift.

13 . The apparatus of claim 1 , wherein the foil sections have substantially uniform, asymmetric foil geometries.

14 . The apparatus of claim 1 , wherein the foil sections have substantially non-uniform foil geometries configured to reduce lift in a mid-span region of the plurality of foil sections as compared to end regions proximate the positive buoyancy device and the submerged end.

15 . A system comprising:
a surface or subsurface buoyancy device; a forward control cable coupled to and extending beneath the buoyancy device; an aft control cable coupled to and extending beneath the buoyancy device; an actuator mounted to the buoyancy device, wherein the actuator is configured to adjust tension in the aft control cable with respect to the forward control cable; and a plurality of foil sections disposed along the forward and aft control cables, wherein: the foil sections are configured to generate lift based on attack angles thereof; and the attack angles of the foil sections vary as a function of the tension.

16 . The system of claim 15 , wherein:
the actuator comprises a linear actuator vertically mounted in the buoyancy device; and the system further comprises a sensor configured to sense tension in one or both of the forward and aft control cables.

17 . The system of claim 16 further comprising a foil controller provided in the buoyancy device and configured to direct the linear actuator to adjust the tension in the aft control cable and thereby regulate lift generated by the plurality of foil sections.

18 . A seismic array comprising:
a plurality of towed seismic sources; and a plurality of dynamically controlled steering systems attached to each of the seismic sources, respectively, wherein each steering system comprises: a positive buoyancy device; a pair of control cables attached to the buoyancy device and extending downward from the buoyancy device to a submerged end; a plurality of foil sections disposed along the control cables between the buoyancy device and the submerged end; and an actuator configured to adjust attack angles of the foil sections by changing a tension in one or both of the control cables.

19 . A method of steering a seismic array comprising:
a plurality of towed seismic devices; and a plurality of dynamically controlled steering systems attached to each of the seismic sources, respectively, wherein each steering system comprises: a positive buoyancy device; a forward control cable coupled to and extending beneath the buoyancy device; an aft control cable coupled to and extending beneath the buoyancy device; a plurality of foil sections disposed along the forward and aft control cables; an actuator mounted to the buoyancy device, wherein the actuator configured to adjust attack angles of the foil sections by changing a tension in one or both of the control cables; and a foil controller configured to direct the actuator to adjust the tension in either or both of the control cables and thereby regulate lift generated by the plurality of foil sections; the method comprising: transmitting data from the foil controller to one or more of the steering systems in order to instantiate a mode in the corresponding actuator; and causing the actuator to adjust tension in the aft control cable with respect to the forward control cable to generate lift for steering the corresponding buoyancy device and attached seismic source.

20 . The method of claim 19 further comprising:
transmitting data from the foil controller to one or more of the steering systems configured to instantiate a minimum or maximum mode; and
causing one or more of the actuators to move to a minimum or maximum detent in order to minimize or maximize the lift.

21 . The method of claim 19 further comprising:
transmitting data from the foil controller to two or more selected ones of the steering systems, wherein the data is configured to instantiate a mode in the selected steering systems to equalize the tension in the respective aft control cables; and
causing the respective actuators exert equal tension on the respective aft control cables in the selected steering systems.

22 . The method of claim 19 further comprising:
transmitting data from the foil controller to the steering systems configured to instantiate a mode designating one of the steering systems as a master steering system; and
causing the actuators to exert tension on the aft cables configured to orient the plurality of foil sections to maintain a fixed lateral separation distance between the buoyancy device of the master steering system and the buoyancy devices of the other steering systems.

23 . The method of claim 19 further comprising:
transmitting data from the foil controller to two or more selected ones of the steering systems, wherein the data is configured to instantiate a mode in the selected steering systems to maintain maximum lateral

Assignees

• Ion Geophysical Corp

Inventors

• Schneider Curt

Classifications

• B63G8/42

  Towed underwater vessels · CPC title

• B63B21/66 Primary

  Equipment specially adapted for towing underwater objects or vessels, e.g. fairings for tow-cables ({paravanes for dragging fishing nets A01K73/02; } salvaging underwater vessels or objects B63C7/00; towed underwater vessels B63G8/42) · CPC title

• G01V1/3817

  Positioning of seismic devices · CPC title

• G01V1/3826 Primary

  dynamic steering, e.g. by paravanes or birds · CPC title

• B63B2211/02

  Oceanography · CPC title