Simultaneous inversion for source wavelet and AVO parameters from prestack seismic data

• US 20040199330A1
• Filed: 04/01/2003
• Published: 10/07/2004
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: Conocophillips Company (ConocoPhillips)
• Original Assignee: Conocophillips Company (ConocoPhillips)
• Inventors: Baumel, Robert T., Anno, Phil D., Routh, Partha Sarathi
• Granted Patent: US 7,072,767 B2
• Time in Patent Office: Days
• US Class Current: 702/14
• CPC Class Codes: G01V 1/28 Processing seismic data, e.g. for interpretation or for event detection G01V1/48 takes precedence
• CPC Class Codes: G01V 1/282 Application of seismic models, synthetic seismograms
• CPC Class Codes: G01V 1/307 for determining seismic attributes, e.g. amplitude, instantaneous phase or frequency, reflection strength or polarity
• CPC Class Codes: G01V 2210/56 De-ghosting; Reverberation compensation
• CPC Class Codes: G01V 2210/614 Synthetically generated data
• CPC Class Codes: G01V 2210/632 Amplitude variation versus offset or angle of incidence [AVA, AVO, AVI]
• CPC Class Codes: G01V 2210/67 Wave propagation modeling

Abstract

The present invention provides for a method and apparatus for seismic data processing. Prestack seismic data is obtained that contains a plurality of reflectors. Non-parallel moveout of the plurality of reflectors is utilized to determine a source wavelet using an L2-Norm and a reflectivity parameter using an L1-Norm. The source wavelet and reflectivity parameters can be determined simultaneously. Source and reflectivity determination may further comprise minimization of a model objective function. The model objective function may be a function of at least one of i) said source wavelet, ii) a gradient parameter and iii) an intercept parameter. An AVO intercept and gradient parameters can be determined using the determined source wavelet and reflectivity parameter. Constraints may be placed on parameters to ensure physically realistic solutions.

Claims

1. A method of seismic data processing, the method comprising:

(a) obtaining prestack seismic data containing a plurality of reflectors;

(b) utilizing non-parallel moveout of said plurality of reflectors to determine a source wavelet using an L2-Norm and a reflectivity parameter using an L1-Norm.

2. The method of claim 1 wherein determining said source wavelet and said reflectivity parameter further comprises minimization of a model objective function.

3. The method of claim 1 further comprising determining AVO intercept and gradient parameters using said determined source wavelet and said determined reflectivity parameter.

4. The method of claim 2 wherein said model objective function is a function of at least one of i) said source wavelet, ii) a gradient parameter and iii) an intercept parameter.

5. The method of claim 1 further comprising placing physical bounds on at least one of:

i) said source wavelet parameter, ii) said reflectivity parameter, and iii) AVO parameters.

6. The method of claim 5 wherein placing physical bounds on said parameters further comprises using an interior-point method.

7. The method of claim 1 further comprising preconditioning said prestack seismic data.

8. The method of claim 7 wherein preconditioning said prestack seismic data includes removing multiples.

9. The method of claim 1 further comprising normalizing said seismic data using at least one of:

i) RMS values within a hyperbolic window and ii) a percentage of median values of a gather of said seismic data.

10. The method of claim 1 wherein the L1-Norm is a type chosen from at least one of:

i) a Huber norm, ii) an Ekblom norm and iii) approximate L1-Norm measures.

18. The method of claim 1 further comprising normalizing said prestack seismic data using at least one of:

i) RMS values within a hyperbolic window and ii) a percentage of median values of a gather of said prestack seismic data.

19. The method of claim 1 wherein said L1-Norms are one of a type chosen from at least one of:

i) a Huber norm, ii) an Ekblom norm and iii) approximate L1-Norm measures.

11. A method of obtaining AVO parameters from seismic data, the method comprising:

(a) obtaining prestack seismic data containing a plurality of reflectors;

(b) utilizing non-parallel moveout of said plurality of reflectors to determine a source wavelet using an L2-Norm and AVO parameters intercept and gradient using L1-Norms.

12. The method of claim 11 wherein determining said source wavelet and said AVO parameters intercept and gradient further comprises minimization of a model objective function.

13. The method of claim 12 wherein said model objective function is a function of at least one of i) said source wavelet, ii) said AVO gradient and iii) said AVO intercept.

14. The method of claim 11 further comprising placing physical bounds on at least one of:

i) said source wavelet parameters, ii) a reflectivity parameter, iii) said AVO gradient parameter and iii) said AVO intercept parameter.

15. The method of claim 14 wherein placing physical bounds on said parameters further comprises using an interior-point method.

16. The method of claim 11 further comprising preconditioning said prestack seismic data.

17. The method of claim 16 wherein preconditioning said prestack seismic data includes removing multiples.

20. A method of obtaining a source wavelet and AVO parameters from seismic data, the method comprising:

(a) obtaining prestack seismic data containing a plurality of reflectors; and

(b) minimizing a model objective function utilizing non-parallel moveout of said plurality of reflectors to simultaneously determine a source wavelet using an L2-Norin and an AVO parameters intercept and gradient using L1-Norms.