Imaging tilted transversely isotropy media with a generalized-screen propagator

Sung Il Shin, Joongmoo Byun, Soon Jee Seol

Research output: Contribution to journalConference article

Abstract

One-way wave equation migration is computationally efficient compared with reverse time migration, and it provides a better subsurface image than ray-based migration algorithms when imaging complex structures. Among many one-way wave-based migration algorithms, we adopted the generalised screen propagator (GSP) to build the migration algorithm. When the wavefield propagates through the large velocity variation in lateral or steeply dipping structures, GSP increases the accuracy of the wavefield in wide angle by adopting higher-order terms induced from expansion of the vertical slowness in Taylor series with each perturbation term. To apply the migration algorithm to a more realistic geological structure, we considered tilted transversely isotropic (TTI) media. The new GSP, which contains the tilting angle as a symmetric axis of the anisotropic media, was derived by modifying the GSP designed for vertical transversely isotropic (VTI) media. To verify the developed TTI-GSP, we analysed the accuracy of wave propagation, especially for the new perturbation parameters and the tilting angle; the results clearly showed that the perturbation term of the tilting angle in TTI media has considerable effects on proper propagation. In addition, through numerical tests, we demonstrated that the developed TTI-GS migration algorithm could successfully image a steeply dipping salt flank with high velocity variation around anisotropic layers.

We expand the vertical transversely isotropic generalised screen propagator into a tilted transversely isotropic generalised screen propagator (TTI-GSP) by adopting tilted coordinates. The validity of the developed algorithm has been tested by increasing the accuracy of wide-angle propagation in TTI-GSP with high-order expansion of the velocity perturbation.
Original languageEnglish
Pages (from-to)349-358
JournalExploration Geophysics
Volume46
Issue number4
StatePublished - 2018 Dec 6

Fingerprint

isotropy
perturbation
anisotropic medium
wave equation
geological structure
wave propagation
salt

Keywords

  • anistoropy
  • generalised screen
  • prestack migration
  • tilited transversely istopic

Cite this

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title = "Imaging tilted transversely isotropy media with a generalized-screen propagator",
abstract = "One-way wave equation migration is computationally efficient compared with reverse time migration, and it provides a better subsurface image than ray-based migration algorithms when imaging complex structures. Among many one-way wave-based migration algorithms, we adopted the generalised screen propagator (GSP) to build the migration algorithm. When the wavefield propagates through the large velocity variation in lateral or steeply dipping structures, GSP increases the accuracy of the wavefield in wide angle by adopting higher-order terms induced from expansion of the vertical slowness in Taylor series with each perturbation term. To apply the migration algorithm to a more realistic geological structure, we considered tilted transversely isotropic (TTI) media. The new GSP, which contains the tilting angle as a symmetric axis of the anisotropic media, was derived by modifying the GSP designed for vertical transversely isotropic (VTI) media. To verify the developed TTI-GSP, we analysed the accuracy of wave propagation, especially for the new perturbation parameters and the tilting angle; the results clearly showed that the perturbation term of the tilting angle in TTI media has considerable effects on proper propagation. In addition, through numerical tests, we demonstrated that the developed TTI-GS migration algorithm could successfully image a steeply dipping salt flank with high velocity variation around anisotropic layers.We expand the vertical transversely isotropic generalised screen propagator into a tilted transversely isotropic generalised screen propagator (TTI-GSP) by adopting tilted coordinates. The validity of the developed algorithm has been tested by increasing the accuracy of wide-angle propagation in TTI-GSP with high-order expansion of the velocity perturbation.",
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Imaging tilted transversely isotropy media with a generalized-screen propagator. / Shin, Sung Il; Byun, Joongmoo; Seol, Soon Jee.

In: Exploration Geophysics, Vol. 46, No. 4, 06.12.2018, p. 349-358.

Research output: Contribution to journalConference article

TY - JOUR

T1 - Imaging tilted transversely isotropy media with a generalized-screen propagator

AU - Shin, Sung Il

AU - Byun, Joongmoo

AU - Seol, Soon Jee

PY - 2018/12/6

Y1 - 2018/12/6

N2 - One-way wave equation migration is computationally efficient compared with reverse time migration, and it provides a better subsurface image than ray-based migration algorithms when imaging complex structures. Among many one-way wave-based migration algorithms, we adopted the generalised screen propagator (GSP) to build the migration algorithm. When the wavefield propagates through the large velocity variation in lateral or steeply dipping structures, GSP increases the accuracy of the wavefield in wide angle by adopting higher-order terms induced from expansion of the vertical slowness in Taylor series with each perturbation term. To apply the migration algorithm to a more realistic geological structure, we considered tilted transversely isotropic (TTI) media. The new GSP, which contains the tilting angle as a symmetric axis of the anisotropic media, was derived by modifying the GSP designed for vertical transversely isotropic (VTI) media. To verify the developed TTI-GSP, we analysed the accuracy of wave propagation, especially for the new perturbation parameters and the tilting angle; the results clearly showed that the perturbation term of the tilting angle in TTI media has considerable effects on proper propagation. In addition, through numerical tests, we demonstrated that the developed TTI-GS migration algorithm could successfully image a steeply dipping salt flank with high velocity variation around anisotropic layers.We expand the vertical transversely isotropic generalised screen propagator into a tilted transversely isotropic generalised screen propagator (TTI-GSP) by adopting tilted coordinates. The validity of the developed algorithm has been tested by increasing the accuracy of wide-angle propagation in TTI-GSP with high-order expansion of the velocity perturbation.

AB - One-way wave equation migration is computationally efficient compared with reverse time migration, and it provides a better subsurface image than ray-based migration algorithms when imaging complex structures. Among many one-way wave-based migration algorithms, we adopted the generalised screen propagator (GSP) to build the migration algorithm. When the wavefield propagates through the large velocity variation in lateral or steeply dipping structures, GSP increases the accuracy of the wavefield in wide angle by adopting higher-order terms induced from expansion of the vertical slowness in Taylor series with each perturbation term. To apply the migration algorithm to a more realistic geological structure, we considered tilted transversely isotropic (TTI) media. The new GSP, which contains the tilting angle as a symmetric axis of the anisotropic media, was derived by modifying the GSP designed for vertical transversely isotropic (VTI) media. To verify the developed TTI-GSP, we analysed the accuracy of wave propagation, especially for the new perturbation parameters and the tilting angle; the results clearly showed that the perturbation term of the tilting angle in TTI media has considerable effects on proper propagation. In addition, through numerical tests, we demonstrated that the developed TTI-GS migration algorithm could successfully image a steeply dipping salt flank with high velocity variation around anisotropic layers.We expand the vertical transversely isotropic generalised screen propagator into a tilted transversely isotropic generalised screen propagator (TTI-GSP) by adopting tilted coordinates. The validity of the developed algorithm has been tested by increasing the accuracy of wide-angle propagation in TTI-GSP with high-order expansion of the velocity perturbation.

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JO - Exploration Geophysics

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