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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-spacephase-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 • 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
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
Motivation • WETom can be accelerated by • solving in a target-oriented way
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
Motivation • Image-space generalized sources • The prestack exploding-reflector modeling (Biondi, 2006) synthesizes areal data from a prestack image obtained with wave-equation methods
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
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
Motivation – reduce costs in WETom x x True Background z 5% cost Optimized z
Agenda • Introduction • Prestack exploding-reflector modeling • Image-space phase-encoded wavefields (ISPEW) • Image-space WETom using ISPEW • Numerical example • Conclusions
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
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
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
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
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Prestack exploding–reflector modeling Original ADCIG Perm ADCIG angle angle z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Prestack exploding–reflector modeling • Combination of modeling experiments • reduces the data size Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Prestack exploding–reflector modeling • Combination of modeling experiments • reduces the data size • generates crosstalk Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Prestack exploding–reflector modeling x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h x h z Prestack exploding–reflector modeling Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Image-space phase-encoded wavefields • Phase-encode the modeling experiments • reduces the data size • attenuates crosstalk Introduction PERM ISPEW WETom using ISPEW Example Conclusion
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
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
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
Image-space phase-encoded wavefields Source wavefield Receiver wavefield Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Image-space phase-encoded wavefields Source wavefield initial condition Receiver wavefield initial condition Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h z Image-space phase-encoded wavefields x z Introduction PERM ISPEW WETom using ISPEW Example Conclusion
Image-space phase encoded wavefields Receiver wavefield Source wavefield x 0 t t x 0 Introduction PERM ISPEW WETom using ISPEW Example Conclusion
x h x h z No phase-encoding Random phase-encoding Image-space phase-encoded wavefields Introduction PERM ISPEW WETom using ISPEW Example Conclusion