Stationary marine vibratory source for seismic surveys

Patent metadata

Field	Value
Publication number	US-9746569-B2
Application number	US-201314138859-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Jun 13, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A seismic data acquisition system is configured to collect seismic data. The system includes a marine source array configured to be attached to a fixed structure floating at the water surface and including vibratory source elements; and a controller configured to control the vibratory source elements so that a beam formed by the source array is steerable.

First claim

What is claimed is:

1. A seismic data acquisition system for collecting seismic data, the system comprising:
a fixed structure floating at the water surface;
a support device directly connected to the fixed structure;
a marine source array suspended in water from the support device, the marine source array including vibratory source elements; and
a controller configured to control the vibratory source elements so that a beam formed by the source array is steerable,
wherein the controller is configured to change a geometry of the source array.

2. The system of claim 1 , wherein the support device supports the source array so that the source array is substantially stationary and the support device is a crane.

3. The system of claim 1 , wherein the controller is configured to change a position of the source array relative to the fixed structure.

4. The system of claim 1 , wherein the controller is configured to steer the beam to a desired region of a subsurface to be surveyed.

5. The system of claim 1 , wherein the controller is located on the source array.

6. The system of claim 1 , wherein the controller is located on the fixed structure.

7. The system of claim 1 , wherein the fixed structure is an oil platform.

8. The system of claim 1 , further comprising:
seismic sensors attached to the ocean bottom.

9. The system of claim 1 , further comprising:
seismic sensors attached to autonomous self-propelled nodes.

10. The system of claim 1 , wherein the controller stores a library of drive signals, each drive signal, when applied to the source array, driving the source elements so that the beam has a given vertical angle with gravity and a given azimuth.

11. A marine source array for generating seismic energy, the source array comprising:
plural vibratory source elements attached directly to a fixed structure substantially stationary in water; and
a controller configured to control the vibratory source elements so that a beam formed by the source array is steerable,
wherein the fixed structure floats at the water surface, and
wherein the controller is configured to change a geometry of the source array.

12. The source array of claim 11 , wherein the source elements are distributed along vertical lines.

13. The source array of claim 11 , wherein a geometry of the source array is adjustable.

14. The source array of claim 11 , wherein the controller is configured to steer the beam to a desired region of a subsurface to be surveyed.

15. The source array of claim 11 , wherein the controller communicates with a global controller located on the fixed structure.

16. The source array of claim 11 , wherein the controller stores a library of drive signals, each drive signal, when applied to the source array, driving the source elements so that the beam has a given vertical angle with gravity and a given azimuth.

17. A method for illuminating a weak underwater target, the method comprising:
suspending a source array from a support device, which is directly connected to a fixed structure that is substantially stationary in water during a seismic survey;
downloading in a controller of the source array a first sweep signal;
applying the first sweep signal to the source array to generate a beam having a first direction while the source array is suspended from the fixed structure; and
emitting the beam toward a subsurface of interest,
wherein the controller is configured to change a geometry of the source array.

18. The method of claim 17 , further comprising:
downloading in the controller of the source array a second sweep signal; and
applying the second sweep signal to the source array to generate a beam having a second direction.

19. The method of claim 17 , further comprising:
calculating a library of frequency sweeps for various directions corresponding to weak illumination targets of the subsurface of interest.

Assignees

• Cgg Services Sa
• Cgg Services Sas

Inventors

• Sallas John
• Thomas Dominique

Classifications

• G01V1/005

  with exploration systems emitting special signals, e.g. frequency swept signals, pulse sequences or slip sweep arrangements · CPC title

• G01V1/3808 Primary

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

• G01V1/3861

  control of source arrays, e.g. for far field control · CPC title

• G01V1/006

  generating single signals by using more than one generator, e.g. beam steering or focusing arrays (G01V1/13, G01V1/3861 take precedence) · CPC title