Vibrator source array load-balancing method and system

Patent metadata

Field	Value
Publication number	US-9482765-B2
Application number	US-201414166205-A
Country	US
Kind code	B2
Filing date	Jan 28, 2014
Priority date	Feb 22, 2013
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

Method and controller for finding a best distribution of source elements that form a vibratory source array. The method includes inputting plural constraints for the source elements; generating plural distributions of the source elements that fulfill the plural constraints; calculating for each distribution a first attribute characterizing the source array; and selecting the best distribution from the plural distributions based on a value of the first attribute.

First claim

What is claimed is:

1. A method for finding a best distribution of marine source elements that form a marine vibratory source array which is towed by a vessel in water, the method comprising:
inputting plural constraints for the marine source elements;
generating plural distributions of the marine source elements that fulfill the plural constraints;
calculating for each distribution a first attribute characterizing the marine source array; and
selecting the best distribution from the plural distributions based on a value of the first attribute,
wherein the first attribute includes a self-impedance part and a mutual-impedance part, the mutual-impedance part describing a load exerted by one marine source element onto another marine source element and the self-impedance part describing a single marine source element.

2. The method of claim 1 , further comprising:
calculating for each distribution a second attribute characterizing the source array; and
selecting the best distribution from the plural distributions based on both the first and second attributes.

3. The method of claim 1 , wherein the plural constraints include a geometry of the source array.

4. The method of claim 3 , wherein the geometry of the source array includes a depth range, a length range and a width range.

5. The method of claim 3 , wherein the geometry includes a number of lines that are towed by a vessel and on which the source elements are distributed when in water.

6. The method of claim 3 , wherein the geometry includes a number of curved lines on which the source elements are distributed when in water.

7. The method of claim 6 , wherein the curved lines has a sinusoid shape.

8. A method for finding a best distribution of source elements that form a vibratory source array, the method comprising:
inputting plural constraints for the source elements;
generating plural distributions of the source elements that fulfill the plural constraints;
calculating for each distribution a first attribute characterizing the source array; and
selecting the best distribution from the plural distributions based on a value of the first attribute,
wherein the first attribute is a maximum total acoustic radiation impedance for the source elements.

9. The method of claim 8 , wherein the maximum total acoustic radiation impedance is selected as the maximum of the total acoustic radiation impedances of the source elements.

10. The method of claim 9 , wherein a total acoustic radiation impedance of a given source element takes into account an influence from all other source elements.

11. The method of claim 10 , further comprising:
calculating for each distribution a second attribute characterizing the source array; and
selecting the best distribution from the plural distributions based on both the first and second attributes.

12. The method of claim 11 , wherein the second attribute is a far-field signal beam shape.

13. The method of claim 12 , wherein the best distribution is selected when the second attribute deviates by less than 20% in beam strength for vertical angles less than 30 degrees and an azimuth angle between about −45 and +45 degrees.

14. A method for finding a best distribution of source elements that form a vibratory source array, the method comprising:
inputting plural constraints for the source elements;
generating plural distributions of the source elements that fulfill the plural constraints;
calculating for each distribution and for each source element a total acoustic radiation impedance;
selecting a maximum total acoustic radiation impedance from total acoustic radiation impedances corresponding to the source elements; and
selecting the best distribution from the plural distributions based on a minimization process applied to the maximum total acoustic impedance.

15. The method of claim 14 , further comprising:
calculating for each distribution a far-field signal shape of a beam generated by the source array; and
selecting the best distribution from the plural distributions when a deviation of the far-field signal shape is less than a threshold.

16. The method of claim 15 , wherein the deviation is less than 20% in beam strength for vertical angles less than 30 degrees and an azimuth angle between about −45 and +45 degrees.

17. The method of claim 14 , further comprising:
implementing the best distribution for the source array during a seismic survey.

18. The method of claim 14 , wherein the step of selecting the best distribution comprises:
calculating a performance index associated with a beam directivity of the source array;
optimizing both the first attribute and the performance index to select the best distribution.

19. A controller for calculating a best distribution of marine source elements that form a marine vibratory source array which is towed by a vessel in water, the controller comprising:
an interface for receiving plural constraints for the marine source elements; and
a processor connected to the interface and configured to,
generate plural distributions of the marine source elements that fulfill the plural constraints;
calculate for each distribution a first attribute characterizing the marine source array; and
select the best distribution from the plural distributions based on a value of the first attribute,
wherein the first attribute includes a self-impedance part and a mutual-impedance part, the mutual-impedance part describing a load exerted by one marine source element onto another marine source element and the self-impedance part describing a single marine source element.

20. The controller of claim 19 , wherein the processor is further configured to:
calculate for each distribution a second attribute characterizing the source array; and
select the best distribution from the plural distributions based on both the first and second attributes.

Assignees

• Cgg Services Sa

Inventors

• Sallas John
• Teyssandier Benoit

Classifications

• G01V1/3843

  Deployment of seismic devices, e.g. of streamers (equipment for marine deployment in general B63B) · CPC title

• G01V1/003 Primary

  Seismic data acquisition in general, e.g. survey design (G01V1/3808, G01V1/42 take precedence) · CPC title

• G01V1/006 Primary

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