DIP GUIDED FULL WAVEFORM INVERSION

• US 20110131020A1
• Filed: 09/09/2010
• Published: 06/02/2011
• Est. Priority Date: 09/09/2009
• Status: Abandoned Application

• Current Assignee: Conocophillips Company (ConocoPhillips)
• Original Assignee: Conocophillips Company (ConocoPhillips)
• Inventors: MENG, Zhaobo
• Application Number:
  US12/878,607
• Publication Number:
  US 20110131020A1
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G01V 1/303 for determining velocity profiles or travel times

Abstract

A method of determining seismic data velocity models comprising dip-guided full waveform inversion that obtains a better velocity model with less computational requirements. DG-FWI quickly converges to provide a better image, obtains better amplitudes, and relies less on lower frequencies. Improved image quality allows detailed seismic analyses, accurate identification of lithological features, and imaging near artifacts and other anomalies.

Claims

1. A method of developing a velocity model comprising:

a) obtaining seismic data,

b) calculating a misfit gradient, ∇

E_m,

c) preparing a dip-guide Φ

from the seismic data,

d) identifying measurement points, x,

e) calculating the misfit gradient with respect to the measurement points, ∇

E_x, and

f) developing a full waveform inversion model, m_DG=Φ

x, using the dip-guide Φ

, wherein the dip-guide is used to condition the full waveform inversion.

2. The method of claim 1, wherein steps (b), (c), (d), (e) or (f) are repeated for one or more iterations (k) to improve forward model resolution.

3. The method of claim 1, wherein said dip-guided inversion model is represented by m_k=Φ

x_k or Δ

m_k=Φ

Δ

x_k, where k is the iteration index.

4. The method of claim 1, wherein the forward model is analyzed for change in the misfit gradient and a full waveform inversion is repeated 1 or more times to improve forward model resolution.

5. The method of claim 1, wherein the seismic data contains 1 or more anomalies including low velocity zones, high velocity zones, gas zones, salt zones, or other feature.

6. The method of claim 1, wherein the changes in misfit are monitored for migration.

7. The method of claim 1, wherein said seismic data is selected from the group consisting of refraction tomography, reflection tomography, transmission tomography, and combinations thereof.

8. The method of claim 1, wherein the full waveform modeling iterations are reduced by dip-guided inversion modelling if compared to full waveform modeling of the initial seismic data.

9. The method of claim 1, wherein the velocity analysis system is selected from the group consisting of 3D Model Builder, Seismitarium, ModSpec, Vest3D, Velocity Model Building (VMB), and Reflection Tomography.

10. A method of developing a velocity model comprising:

a) obtaining seismic data,

b) calculating the misfit gradient, ∇

E_m,

c) developing a full waveform inversion model change Δ

m_FWI using the misfit gradient ∇

E_m,

d) developing a new full waveform inversion model m from the previous full wavefrom inversion model m=m_DG+Δ

m_FWI, and

e) repeating steps (b), (c), or (d) one or more times to increase resolution

wherein a dip-guided inversion model provides an initial model for full waveform inversion.

11. The method of claim 10, wherein steps (b), (c), (d), (e) or (f) are repeated for one or more iterations (k) to improve forward model resolution.

12. The method of claim 10, wherein said dip-guided inversion model is represented by m_k=Φ

x_k or Δ

m_k=Φ

Δ

x_k, where k is the iteration index.

13. The method of claim 10, wherein the forward model is analyzed for change in the misfit gradient and a full waveform inversion is repeated 1 or more times to improve forward model resolution.

14. The method of claim 10, wherein the seismic data contains 1 or more anomalies including low velocity zones, high velocity zones, gas zones, salt zones, or other feature.

15. The method of claim 10, wherein the changes in misfit are monitored for migration.

16. The method of claim 10, wherein said seismic data is selected from the group consisting of refraction tomography, reflection tomography, transmission tomography, and combinations thereof.

17. The method of claim 10, wherein the full waveform modeling iterations are reduced by dip-guided inversion modelling if compared to full waveform modeling of the initial seismic data.

18. The method of claim 10, wherein the velocity analysis system is selected from the group consisting of 3D Model Builder, Seismitarium, ModSpec, Vest3D, Velocity Model Building (VMB), and Reflection Tomography.

19. A method of developing a velocity model comprising:

a) obtaining seismic data on a computer readable media,

b) transferring the seismic data to a velocity analysis system,

c) calculating a dip-guide from the seismic data,

d) performing a full waveform inversion model in the velocity analysis system,

wherein the dip-guide is used to condition the full waveform inversion.

20. The method of claim 19, wherein steps (b), (c), (d), (e) or (f) are repeated for one or more iterations (k) to improve forward model resolution.

21. The method of claim 19, wherein said dip-guided inversion model is represented by m_k=Φ

x_k or Δ

m_k=Φ

Δ

x_k, where k is the iteration index.

22. The method of claim 19, wherein the forward model is analyzed for change in the misfit gradient and a full waveform inversion is repeated 1 or more times to improve forward model resolution.

23. The method of claim 19, wherein the seismic data contains 1 or more anomalies including low velocity zones, high velocity zones, gas zones, salt zones, or other feature.

24. The method of claim 19, wherein the changes in misfit are monitored for migration.

25. The method of claim 19, wherein said seismic data is selected from the group consisting of refraction tomography, reflection tomography, transmission tomography, and combinations thereof.

26. The method of claim 19, wherein the full waveform modeling iterations are reduced by dip-guided inversion modelling if compared to full waveform modeling of the initial seismic data.

27. The method of claim 19, wherein the velocity analysis system is selected from the group consisting of 3D Model Builder, Seismitarium, ModSpec, Vest3D, Velocity Model Building (VMB), and Reflection Tomography.