Method for performing stratrigraphically-based seed detection in a 3-D seismic data volume

• US 20040062145A1
• Filed: 09/03/2003
• Published: 04/01/2004
• Est. Priority Date: 09/26/2002
• Status: Active Grant

• Current Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Original Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Inventors: Czernuszenko, Marek K., Dunn, Paul A.
• Granted Patent: US 7,024,021 B2
• Time in Patent Office: Days
• US Class Current: 367/72
• CPC Class Codes: G01V 1/288 Event detection in seismic signals, e.g. microseismics G01V1/36 takes precedence

Abstract

The invention is a method for performing a stratigraphically-based seed detection in a 3-D seismic data volume. The method incorporates criteria that honor the layered nature of the subsurface so that the resulting seismic objects are stratigraphically reasonable. The method may be used to extract from a seismic data volume all seismic objects that satisfy the input criteria. Alternatively, the method may be used to determine the size and shape of a specific seismic object in a seismic data volume.

Claims

1. A method for seed detection of seismic objects in a 3-D seismic data volume, said 3-D seismic data volume comprising a plurality of vertical seismic data traces, said method comprising the steps of:

(a) determining the value of a preselected seismic attribute at a plurality of data points along each seismic data trace;

(b) selecting a first set of criteria for classifying each seismic data trace based on said attribute values into trace segments that are either acceptable or unacceptable for inclusion in a seismic object;

(c) selecting a second set of criteria for allowing or preventing lateral propagation of a seismic object from one seismic data trace to an adjacent seismic data trace;

(d) selecting an initial data point in said 3-D seismic data volume as a seed point and attempting to grow a seismic object around said seed point based on said first and second sets of criteria;

(e) repeating step (d) for each other data point in said 3-D seismic data volume; and

(f) outputting seismic objects that satisfy pre-selected criteria for minimum and maximum size.

2. The method of claim 1, wherein said first set of criteria include threshold criteria for the value of said preselected seismic attribute and trace segment length requirements.

3. The method of claim 2, wherein said threshold criteria include minimum and maximum thresholds for the value of said preselected seismic attribute.

4. The method of claim 2, wherein said trace segment length requirements include minimum and maximum lengths for acceptable trace segments.

5. The method of claim 4, wherein trace segments exceeding the maximum length requirement are trimmed symmetrically to the maximum length and then accepted.

6. The method of claim 1, wherein lateral propagation of a seismic object from one seismic data trace to an adjacent seismic data trace is allowed only at peaks (local maxima) or troughs (local minima) of acceptable data trace segments, and wherein said second set of criteria includes maximum vertical offset between corresponding acceptable peaks or troughs on adjacent seismic data traces.

7. The method of claim 6, wherein said maximum vertical offset is spatially variable and is derived from calculation of regional stratigraphic dip.

8. The method of claim 1, wherein said preselected seismic attribute is seismic amplitude.

9. The method of claim 1, wherein said preselected seismic attribute is acoustic impedance.

10. The method of claim 1, wherein said preselected seismic attribute is discontinuity.

11. The method of claim 1, said method further comprising the step of preventing any seismic object from including more than one discrete segment of any seismic data trace.

12. The method of claim 1 wherein lateral propagation is controlled by checking the amount of vertical offset of the local minimum or maximum.

13. The method of claim 1 wherein lateral growth is controlled by shape of the wavelet.

14. The method of claim 13 further comprising correlating the shape of the wavelet to a parameter of interest and using the correlation of the shape of the parameter of interest to estimate the parameter of interest throughout a seismic survey.

15. The method of claim 14 where in the parameter of interest is chosen from the group comprising net to gross, porosity, fluid type, saturation, lithology and facies and any combination thereof.

16. The method of claim 1 wherein the lateral growth is controlled by a trace-to-trace statistical correlation.

17. A method for determining the size and shape of a seismic object in a 3-D seismic data volume, said 3-D seismic data volume comprising a plurality of vertical seismic data traces, said method comprising the steps of:

(a) determining the value of a preselected seismic attribute at a plurality of data points along each seismic data trace;

(b) selecting a first set of criteria for classifying each seismic data trace based on said attribute values into trace segments that are either acceptable or unacceptable for inclusion in said seismic object;

(c) selecting a second set of criteria for allowing or preventing lateral propagation of said seismic object from one seismic data trace to an adjacent seismic data trace;

(d) selecting a seed point falling within said seismic object and growing said seismic object around said seek point based on said first and second sets of criteria; and

(e) outputting the size and shape of said seismic object.

18. The method of claim 17, wherein said first set of criteria include threshold criteria for the value of said preselected seismic attribute and trace segment length requirements.

19. The method of claim 18, wherein said threshold criteria include minimum and maximum thresholds for the value of said preselected seismic attribute.

20. The method of claim 18, wherein said trace segment length requirements include minimum and maximum lengths for acceptable trace segments.

21. The method of claim 20, wherein trace segments exceeding the maximum length requirement are trimmed symmetrically to the maximum length and then accepted.

22. The method of claim 17, wherein lateral propagation of said seismic object from one seismic data trace to an adjacent seismic data trace is allowed only at peaks (local maxima) or troughs (local minima) of acceptable data trace segments, and wherein said second set of criteria includes maximum vertical offset between corresponding acceptable peaks or troughs on adjacent seismic data traces.

23. The method of claim 22, wherein said maximum vertical offset is spatially variable and is derived from calculation of regional stratigraphic dip.

24. The method of claim 17, wherein said preselected seismic attribute is seismic amplitude.

25. The method of claim 17, wherein said preselected seismic attribute is acoustic impedance.

26. The method of claim 17, wherein said preselected seismic attribute is discontinuity.

27. The method of claim 17, said method further comprising the step of preventing said seismic object from including more than one discrete segment of any seismic data trace.

28. The method of claim 17 where in lateral propagation is controlled by checking the amount of vertical offset of a local maximum or minimum.

29. The method of claim 17 wherein lateral growth is controlled by shape of the wavelet.

30. The method of claim 29 further comprising correlating the shape of the wavelet to a parameter of interest and using the correlation of the shape to the parameter of interest to estimate the parameter of interest throughout a seismic survey.

31. The method of claim 30 wherein the parameter of interest is chosen from the group comprising net to gross, porosity, fluid type, saturation, lithology and facies and any combination thereof.

32. The method of claim 17 wherein the lateral growth is controlled by a trace-to-trace statistical correlation.