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Wave-equation tomography using image-space phase-encoded data

Wave-equation tomography using image-space phase-encoded data. Claudio Guerra*, Yaxun Tang and Biondo Biondi. SEG Houston – 2009. Motivation. Velocity determination is a difficult task, especially in areas of complex geology. Motivation.

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Wave-equation tomography using image-space phase-encoded data

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  1. Wave-equation tomography using image-spacephase-encoded data Claudio Guerra*, Yaxun Tang and Biondo Biondi SEG Houston – 2009

  2. Motivation • Velocity determination is a difficult task, especially in areas of complex geology

  3. Motivation • Velocity determination is a difficult task, especially in areas of complex geology • Wave-equation tomography (WETom) is a robust method to estimate the slowness model • uses wavefields as carriers of information • insensitive to multi-pathing

  4. Motivation • Velocity determination is a difficult task, especially in areas of complex geology • Wave-equation tomography (WETom) is a robust method to estimate the slowness model • uses wavefields as carriers of information • insensitive to multi-pathing • computationally expensive

  5. Motivation • WETom can be accelerated by • solving in a target-oriented way

  6. Motivation • WETom can be accelerated by • solving in a target-oriented way • using generalized sources • Shen and Symes (2008) – image-space WETom • Vigh and Starr (2008) – data-space WETom

  7. Motivation • Image-space generalized sources • The prestack exploding-reflector modeling (Biondi, 2006) synthesizes areal data from a prestack image obtained with wave-equation methods

  8. x z ? ? ? Motivation • Image-space generalized sources • The prestack exploding-reflector modeling (Biondi, 2006) synthesizes areal data from a prestack image obtained with wave-equation methods • Wavefields are upward propagated to the top of thetarget saving computer time

  9. Motivation • Image-space generalized sources • The prestack exploding-reflector modeling (Biondi, 2006) synthesizes areal data from a prestack image obtained with wave-equation methods • Wavefields are upward propagated to the top of thetarget saving computer time • Additional savings when combining modeling experiments

  10. Motivation – reduce costs in WETom x x True Background z 5% cost Optimized z

  11. Agenda • Introduction • Prestack exploding-reflector modeling • Image-space phase-encoded wavefields (ISPEW) • Image-space WETom using ISPEW • Numerical example • Conclusions

  12. Prestack exploding–reflector modeling • The exploding reflector assumes all energy focused at zero-subsurface offset • Generalizes the exploding reflector concept Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  13. Prestack exploding–reflector modeling • Generalizes the exploding reflector concept • Uses a partially focused wave-equation prestack image as initial condition Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  14. Prestack exploding–reflector modeling • Generalizes the exploding reflector concept • Uses a partially focused wave-equation prestack image as initial condition • Models areal source and receiver wavefields suitable for MVA Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  15. Prestack exploding–reflector modeling • The exploding–reflector assumes zero–subsurface offset reflectivity • Slowness inaccuracy spreads energy to nonzero-offsets • Generalizes the exploding reflector concept • Uses a partially focused wave-equation prestack image as initial condition • Models areal source and receiver wavefields suitable for MVA • Can be used in a target–oriented way since the wavefields can be collected at any depth Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  16. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  17. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  18. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  19. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  20. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  21. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  22. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  23. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  24. Prestack exploding–reflector modeling Original ADCIG Perm ADCIG angle angle z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  25. Prestack exploding–reflector modeling • Combination of modeling experiments • reduces the data size Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  26. Prestack exploding–reflector modeling • Combination of modeling experiments • reduces the data size • generates crosstalk Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  27. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  28. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  29. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  30. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  31. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  32. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  33. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  34. x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  35. x h x h z Prestack exploding–reflector modeling Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  36. Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  37. Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size • attenuates crosstalk Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  38. Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size • attenuates crosstalk • keeps the kinematic information Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  39. Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size • attenuates crosstalk • keeps the kinematic information • requires picking the prestack image Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  40. Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size • attenuates crosstalk • keeps the kinematic information • requires picking the prestack image • allows selecting key reflectors Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  41. Image-space phase-encoded wavefields Source wavefield Receiver wavefield Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  42. Image-space phase-encoded wavefields Source wavefield initial condition Receiver wavefield initial condition Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  43. x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  44. x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  45. x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  46. x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  47. x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  48. x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  49. Image-space phase encoded wavefields Receiver wavefield Source wavefield x 0 t t x 0 Introduction PERM ISPEW WETom using ISPEW Example Conclusion

  50. x h x h z No phase-encoding Random phase-encoding Image-space phase-encoded wavefields Introduction PERM ISPEW WETom using ISPEW Example Conclusion

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