Method and device for determining a driving signal for vibroseis marine sources

Patent metadata

Field	Value
Publication number	US-9618641-B2
Application number	US-201213687084-A
Country	US
Kind code	B2
Filing date	Nov 28, 2012
Priority date	Oct 19, 2011
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

Controller and method for determining a driving signal of a vibro-acoustic source element that is configured to generate acoustic waves in water. The method includes estimating at least one physical constraint of the vibro-acoustic source element; modeling a ghost function determined by a surface of the water; setting a target energy spectrum density to be emitted by the vibro-acoustic source element during the driving signal; and determining the driving signal in a controller based on at least one physical constraint, the ghost function, and the target energy spectrum density.

First claim

What is claimed is:

1. A method for determining a driving signal of a vibro-acoustic source element that is configured to generate acoustic waves in water, the method comprising:
estimating at least one physical constraint related to operating the vibro-acoustic source element;
modeling a ghost function that represents an effect of a surface of the water;
setting a target energy spectrum density to be emitted by the vibro-acoustic source element during the driving signal; and
determining the driving signal in a controller based on the at least one physical constraint, the ghost function, and the target energy spectrum density.

2. The method of claim 1 , wherein the vibro-acoustic source element has an electro-magnetic actuator configured to actuate a piston.

3. The method of claim 2 , wherein the at least one physical constraint includes a combination of one or more of a maximum displacement of the piston, a maximum speed of the piston, a maximum current of a driving mechanism that drives the electro-magnetic actuator, and a maximum voltage of the driving mechanism.

4. The method of claim 2 , wherein the at least one physical constraint includes a maximum displacement of the piston, a maximum speed of the piston, a maximum current of a driving mechanism that drives the electro-magnetic actuator, and a maximum voltage of the driving mechanism.

5. The method of claim 4 , further comprising:
determining a domain of operation of the vibro-acoustic source element as an intersection of the maximum displacement, the maximum speed, the maximum current and the maximum voltage curves.

6. The method of claim 1 , wherein the ghost function takes into account a reflection of a wave from the surface of the water.

7. The method of claim 1 , wherein the target energy spectrum density is flat.

8. The method of claim 1 , wherein a majority of time corresponding to the driving signal corresponds to a low frequency range.

9. A controller configured to determine a driving signal of a vibro-acoustic source element that is configured to generate acoustic waves in water, the controller comprising:
a processor configured to,
estimate at least one physical constraint related to operating the vibro-acoustic source element;
receive a ghost function modeled to represent an effect of a surface of the water;
receive a target energy spectrum density to be emitted by the vibro-acoustic source element during the driving signal; and
calculate the driving signal based on the at least one physical constraint, the ghost function, and the target energy spectrum density.

10. The controller of claim 9 , wherein the at least one physical constraint includes a combination of one or more of a maximum displacement of a piston of the vibro-acoustic source element, a maximum speed of the piston, a maximum current of a driving mechanism that drives the electro-magnetic actuator, and a maximum voltage of the driving mechanism.

11. The controller of claim 9 , wherein the at least one physical constraint includes a maximum displacement of a piston of the vibro-acoustic source element, a maximum speed of the piston, a maximum current of a driving mechanism that drives the electro-magnetic actuator, and a maximum voltage of the driving mechanism.

12. The controller of claim 11 , further comprising:
determining a domain of operation of the vibro-acoustic source element as an intersection of the maximum displacement, the maximum speed, the maximum current and the maximum voltage curves.

13. The controller of claim 9 , wherein the ghost function takes into account a reflection of a wave from the surface of the water.

14. The controller of claim 9 , wherein the target energy spectrum density is flat.

15. The controller of claim 9 , wherein a majority of time corresponding to the driving signal corresponds to a low frequency range.

16. A seismic survey system comprising:
at least one vibro-acoustic source element configured to generate acoustic waves by moving a piston with an electro-magnetic actuator;
a driving mechanism connected to the electro-magnetic actuator and configured to drive the electro-magnetic actuator to generate the acoustic waves; and
a controller configured to generate a driving signal for the driving mechanism for generating acoustic waves in water,
wherein the controller is configured to
estimate at least one physical constraint related to operating the vibro-acoustic source element;
receive a ghost function modeled to represent an effect of a surface of the water;
receive a target energy spectrum density to be emitted by the vibro-acoustic source element during the driving signal; and
calculate the driving signal based on the at least one physical constraint, the ghost function, and the target energy spectrum density.

17. The system of claim 16 , wherein the at least one physical constraint includes a combination of one or more of a maximum displacement of a piston of the vibro-acoustic source element, a maximum speed of the piston, a maximum current of a driving mechanism that drives the electro-magnetic actuator, and a maximum voltage of the driving mechanism.

Assignees

• Cggveritas Services Sa
• Cgg Services Sas

Inventors

• Teyssandier Benoit
• Ruet Laurent

Classifications

• G01V2210/1293

  Sea · CPC title

• G01V1/38 Primary

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

• G01V1/005 Primary

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

• G01V1/02

  Generating seismic energy {(G01V1/003 takes precedence)} · CPC title