Cross-line source separation based on cross-line streamer separation

Patent metadata

Field	Value
Publication number	US-10324203-B2
Application number	US-201715617075-A
Country	US
Kind code	B2
Filing date	Jun 8, 2017
Priority date	Dec 14, 2016
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A method for a marine seismic survey can include towing streamers that are spaced apart in a cross-line direction by a streamer separation (L) and towing seismic source elements that are spaced apart in the cross-line direction by a source separation based on an integer (k), an inverse of a quantity of the seismic source elements (1/S), and the streamer separation as represented by (k+1/S)L. The seismic source elements can be actuated and seismic signals can be detected at each of a plurality of receivers on the streamers.

First claim

What is claimed is:

1. A method for a marine seismic survey, comprising:
towing streamers that are spaced apart in a cross-line direction by a streamer separation (L);
towing seismic source elements that are spaced apart in the cross-line direction by a source separation based on a positive integer (k), an inverse of a quantity of the seismic source elements (1/S), and the streamer separation as represented by (k+1/S)L;
actuating the seismic source elements; and
detecting seismic signals at each of a plurality of receivers on the streamers.

2. The method of claim 1 , further comprising determining a value of the positive integer (k) based on a quantity of the streamers (N).

3. The method of claim 1 , further comprising determining a value of the positive integer (k) between one and one less than a quantity of the plurality of streamers (N−1), inclusive.

4. The method of claim 1 , further comprising determining a value of the positive integer (k) between one and half of the quantity of the plurality of streamers (N/2), inclusive.

5. The method of claim 1 , further comprising determining a value of the positive integer (k) between one and half of one less than the quantity of the plurality of streamers ((N−1)/2), inclusive.

6. The method of claim 1 , wherein towing the streamers and towing the seismic source elements include towing the streamers and the seismic source elements by a marine survey vessel.

7. The method of claim 1 , wherein towing the streamers includes towing the streamers by a first marine seismic survey vessel, and
wherein towing the seismic source elements includes towing the seismic source elements by a second marine survey vessel.

8. The method of claim 1 , wherein towing the streamers includes towing the streamers by a first marine seismic survey vessel, and
wherein towing the seismic source elements includes:
towing a first one of the seismic source elements by a second marine survey vessel; and
towing a second one of the seismic source elements by a third marine survey vessel.

9. An array, comprising:
a plurality of seismic source elements configured to be towed by a marine survey vessel, wherein a cross-line source separation between adjacent seismic source elements is at least based on:
a positive integer (k);
a cross-line streamer separation (L) between each of a plurality of streamers to be towed by the marine survey vessel for a particular marine seismic survey; and
an inverse of a quantity of the plurality of seismic source elements (1/S).

10. The array of claim 9 , wherein the cross-line source separation is a sum of the positive integer (k) and the inverse of the quantity of the plurality of seismic source elements (1/S) that are adjacent in a cross-line direction multiplied by the cross-line streamer separation (L).

11. The array of claim 9 , wherein the cross-line streamer separation (L) is an average cross-line streamer separation.

12. The array of claim 9 , wherein the plurality of seismic source elements comprises a first seismic source sub-array,
wherein the array further comprises a second seismic source sub-array comprising a different plurality of seismic source elements, wherein the first seismic source sub-array is adjacent to the second seismic source sub-array, and
wherein the cross-line source separation is a distance between the first seismic source sub-array and the second seismic source sub-array and is based on:
the positive integer (k);
the cross-line streamer separation (L); and
an inverse of a quantity of seismic source sub-arrays (1/S A ).

13. The array of claim 9 , wherein the cross-line source separation is greater than the cross-line streamer separation (L).

14. A method for a marine seismic survey, comprising:
performing a marine seismic survey with a plurality of seismic source elements and a plurality of streamers, wherein a cross-line source separation between each of the plurality of seismic source elements is directly proportional to a cross-line streamer separation (L) between each of the plurality of streamers by:
a sum of a positive integer (k) less than or equal to a quantity (N) of the plurality of streamers; and
an inverse of a quantity of the plurality of seismic source elements (1/S).

15. The method of claim 14 , further comprising determining a value of the positive integer (k) for a particular subline coverage.

16. The method of claim 14 , further comprising increasing a subline coverage via increasing a value of the positive integer (k).

17. The method of claim 14 , further comprising maintaining a marine seismic survey resolution while increasing the cross-line source separation without increasing the quantity (N) of the plurality of streamers.

18. The method of claim 14 , further comprising performing the marine seismic survey along two adjacent sail lines using a cross-line sail line separation between the two adjacent sail lines such that a subline of one of the two adjacent sail lines complements a subline of another one of the two adjacent sail lines.

19. The method of claim 14 , further comprising performing the marine seismic survey along two adjacent sail lines using a cross-line sail line separation between the two adjacent sail lines such that a full fold subline of one of the two adjacent sail lines complements a zero fold subline of another one of the two adjacent sail lines.

20. The method of claim 19 , further comprising maintaining a cross-line subline separation between the complementing sublines of the one of the two adjacent sail lines and the complementing sublines of the other one of the two adjacent sail lines.

21. The method of claim 14 , further comprising subtracting a predicted multiple from the marine seismic survey data.

22. A method to manufacture a geophysical data product, the method comprising:
determining an arrangement of a plurality of seismic source elements and a plurality of streamers such that a cross-line source separation between each of the plurality of seismic source elements is directly proportional to a cross-line streamer separation (L) between each of the plurality of streamers by:
a sum of a positive integer (k) less than or equal to a quantity (N) of the plurality of streamers; and
an inverse of a quantity of the plurality of seismic source elements (1/S);

obtaining geophysical data from a marine seismic survey performed with the determined arrangement of the plurality of seismic source elements and the plurality of streamers;
processing the geophysical data to generate the geophysical data product; and
recording the geophysical data product on a non-transitory machine-readable medium.

23. The method of claim 22 , wherein processing the geophysical data comprises processing the geophysical data offshore.

Assignees

• Pgs Geophysical As

Inventors

• Long Andrew Samuel

Classifications

• G01V1/3808 Primary

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

• G01V1/3817

  Positioning of seismic devices · CPC title

• G01V1/36

  Effecting static or dynamic corrections on records, e.g. correcting spread; Correlating seismic signals; Eliminating effects of unwanted energy · CPC title

• G01V1/3835

  measuring position, e.g. by GPS or acoustically · CPC title

• G01V1/38

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