Method for identifying and removing multiples for imaging with beams

• US 7,715,986 B2
• Filed: 05/22/2007
• Issued: 05/11/2010
• Est. Priority Date: 05/22/2007
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Wang, Yue, Qin, Fuhao, Hill, Ross, Nemeth, Tamas
• Primary Examiner(s): Tsai; Carol S
• Assistant Examiner(s): Suglo; Janet L
• Application Number:
  US11/751,975
• Publication Number:
  US 20080294346A1
• Time in Patent Office: 1,085 Days
• Field of Search: 702/14, 702/16, 702/17, 703/5, 367/73, 367/24
• US Class Current: 702/14
• CPC Class Codes: G01V 1/364 Seismic filtering G01V1/37 takes precedence
• CPC Class Codes: G01V 2210/56 De-ghosting; Reverberation compensation

Abstract

The present invention incorporates the use of model-driven and data-driven methodologies to attenuate multiples in seismic data utilizing a prediction model which includes multiply-reflected, surface-related seismic waves. The present invention includes beam techniques and convolving a predicted multiples beam with a segment of a modeled pegleg beam to obtain a convolved multiples beam. The convolved multiples beam can then he deconvolved to attenuate the multiples that are present in the original input beam.

Claims

1. A computer-implemented method of attenuating multiples in multiply-reflected, surface-related seismic waves within the earth'"'"'s subsurface utilizing a computer system comprising at least one processor configured to communicate with at least one computer memory device and configured for executing computer program code for performing the method comprising:

(a) initializing an earth model, on at least one processor of the computing system, related to a geological volume within the earth'"'"'s subsurface;

(b) selecting a beam dataset, stored on at least one memory device, derived from seismic data related to the geological volume;

(c) selecting an input beam from the beam dataset;

(d) selecting a multiple-generating surface from the earth model;

(e) selecting a time gate;

(f) executing computer program code, on at least one processor of the computing system, configured for determining a stationary pegleg utilizing the input beam, the multiple-generating surface and the time gate;

(g) executing computer program code, on at least one processor of the computing system, configured for obtaining a primary beam which corresponds to the stationary pegleg;

(h) executing computer program code, on at least one processor of the computing system, configured for obtaining a modeled pegleg beam that is related to the primary beam;

(i) executing computer program code, on at least one processor of the computing system, configured for convolving the primary beam and the modeled pegleg beam to obtain a convolved multiples beam;

(j) executing computer program code, on at least one processor of the computing system, configured for deconvolving the convolved multiples beam with the input beam to remove the multiples in the input beam; and

(k) repeating steps (c) to (j) for a plurality of beams, steps (d) to (j) for a plurality of multiple-generating surfaces, and steps (e) to (j) for a plurality of time gates, to generate an image of the geological volume.

2. The method of claim 1 which includes accumulating the convolved multiples beams before deconvolving the input beam with the convolved multiples beam to remove the multiples in the input beam.

3. The method of claim 1 wherein the step of selecting the time gate includes selecting the entire input beam.

4. The method of claim 1 wherein the step of selecting the time gate includes selecting a portion of the input beam.

5. The method of claim 1 wherein the stationary pegleg is determined for a source-side multiple.

6. The method of claim 1 wherein the stationary pegleg is determined for a detector-side multiple.

7. The method of claim 1 wherein the stationary pegleg is determined for both a source-side multiple and a detector-side multiple.

8. The method of claim 1 wherein determining the stationary pegleg includes spraying rays from a detector location, the detector location being based on the input beam, and determining a stationary pegleg that is related to one of the rays sprayed from the detector location.

9. The method of claim 1 wherein convolving the primary beam and the modeled pegleg beam to obtain the convolved multiples beam includes transforming the primary beam into a predicted multiples beam, and convolving the predicted multiples beam with a segment of the modeled pegleg beam to obtain a convolved multiples beam, the segment of the modeled pegleg beam starting at the multiple-generating surface and ending at a deeper surface or at the end of a pre-determined time interval.

10. The method of claim 1 wherein the convolved multiples beam is obtained as a direct convolution of the primary beam with the modeled pegleg beam.

11. The method of claim 1 wherein the beams are defined as energy components that are partially localized in space and dip.

12. The method of claim 1 wherein the beam dataset includes Gaussian beams.

13. The method of claim 1 wherein the beam dataset includes beams with complex rays.

14. The method of claim 1 wherein the beam dataset includes controlled beams.

15. The method of claim 1 wherein the beam dataset includes finite-difference beams.

16. A computer-implemented method of attenuating multiples in multiply-reflected, surface-related seismic waves within the earth'"'"'s subsurface utilizing a computer system comprising at least one processor configured to communicate with at least one computer memory device and configured for executing computer program code for performing the method comprising:

(a) initializing an earth model, on at least one processor of the computing system, related to a geological volume within the earth'"'"'s subsurface;

(b) selecting a beam dataset, stored on at least one memory device, derived from seismic data related to the geological volume;

(c) selecting an input beam from the beam dataset;

(d) selecting a multiple-generating surface from the earth model;

(e) selecting a time gate;

(f) selecting a pegleg;

(g) executing computer program code, on at least one processor of the computing system, configured for obtaining a primary beam which corresponds to the pegleg;

(h) executing computer program code, on at least one processor of the computing system, configured for obtaining a modeled pegleg beam that is related to the primary beam;

(i) executing computer program code, on at least one processor of the computing system, configured for convolving the primary beam and the modeled pegleg beam to obtain a convolved multiples beam;

(j) executing computer program code, on at least one processor of the computing system, configured for deconvolving the convolved multiples beam with the input beam to remove the multiples in the input beam; and

(k) repeating steps (c) to (j) for a plurality of beams, steps (d) to (j) for a plurality of multiple-generating surfaces, and steps (e) to (j) for a plurality of time gates, to generate an image of the geological volume.

17. The method of claim 16 which includes accumulating the convolved multiples beams before deconvolving the input beam with the convolved multiples beam to remove the multiples in the input beam.

18. The method of claim 16 wherein the step of selecting the time gate includes selecting the entire input beam.

19. The method of claim 16 wherein the step of selecting the time gate includes selecting a portion of the input beam.

20. The method of claim 16 wherein the pegleg is selected for a source-side multiple.

21. The method of claim 16 wherein the pegleg is selected for a detector-side multiple.

22. The method of claim 16 wherein the pegleg is selected for both a source-side multiple and a detector-side multiple.

23. The method of claim 16 wherein a stationary pegleg utilizing the input beam, the multiple-generating surface and the time gate is determined, and the selected pegleg is related to the stationary pegleg.

24. The method of claim 23 wherein the stationary pegleg is determined for a source-side multiple.

25. The method of claim 23 wherein the stationary pegleg is determined for a detector-side multiple.

26. The method of claim 23 wherein the stationary pegleg is determined for both a source-side multiple and a detector-side multiple.

27. The method of claim 23 wherein the pegleg is chosen by selecting a range of ray parameter values around a ray parameter value of the stationary pegleg.

28. The method of claim 23 wherein the pegleg is chosen by selecting a range of locations around an arrival location of the stationary pegleg.

29. The method of claim 16 wherein the beams are defined as energy components that are partially localized in space and dip.

30. The method of claim 16 wherein the beam dataset includes Gaussian beams.

31. The method of claim 16 wherein the beam dataset includes complex beams.

32. The method of claim 16 wherein the beam dataset includes controlled beams.

33. The method of claim 16 wherein the beam dataset includes finite-difference beams.

34. A computer implemented method of attenuating multiples in multiply-reflected, surface-related seismic waves within the earth'"'"'s subsurface utilizing a computer system comprising at least one processor configured to communicate with at least one computer memory device and configured for executing computer program code for performing the method comprising:

(a) selecting an input beam from a beam dataset, stored on at least one memory device, using a computer;

(b) selecting a time gate;

(c) selecting a pegleg;

(d) executing computer program code, on at least one processor of the computing system, configured for obtaining a primary beam which corresponds to the pegleg;

(e) executing computer program code, on at least one processor of the computing system, configured for obtaining a modeled pegleg beam that is related to the primary beam;

(f) executing computer program code, on at least one processor of the computing system, configured for convolving the primary beam and the modeled pegleg beam to obtain a convolved multiples beam;

(g) executing computer program code, on at least one processor of the computing system, configured for deconvolving the convolved multiples beam with the input beam to remove the multiples in the input beam; and

(h) repeating steps (c) to (g) for a plurality of beams, steps (d) to (g) for a plurality of multiple-generating surfaces, and steps (e) to (g) for a plurality of time gates, to generate an image of the geological volume.

35. The method of claim 34 which includes accumulating the convolved multiples beams before deconvolving the input beam with the convolved multiples beam to remove the multiples in the input beam.

36. The method of claim 34 wherein the step of selecting the time gate includes selecting the entire input beam.

37. The method of claim 34 wherein the step of selecting the time gate includes selecting a portion of the input beam.

38. The method of claim 34 wherein the pegleg is selected for a source-side multiple.

39. The method of claim 34 wherein the pegleg is selected for a detector-side multiple.

40. The method of claim 34 wherein the pegleg is selected for both a source-side multiple and a detector-side multiple.

41. The method of claim 34 wherein the beams are defined as energy components that are partially localized in space and dip.

42. The method of claim 34 wherein the beam dataset includes Gaussian beams.

43. The method of claim 34 wherein the beam dataset includes beams with complex rays.

44. The method of claim 34 wherein the beam dataset includes controlled beams.

45. The method of claim 34 wherein the beam dataset includes finite-difference beams.