3D illumination analysis using wave equation based propagator XiaoBi Xie University of California, S

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3D illumination analysis using wave equation
based propagator Xiao-Bi Xie University of
California, Santa Cruz Shengwen Jin Screen
Imaging Technology Inc. Ru-Shan Wu University
of California, Santa Cruz October, 2003,
Dallas, Texas
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Outline

• O Introduction
• O Illumination analysis
• O Directional illumination
• O Acquisition dip-response
• O 3D numerical examples using SEG/EAGE salt
  model
• O Summary

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Outline

• O Introduction
• O Illumination analysis
• O Directional illumination
• O Acquisition dip-response
• O 3D numerical examples using SEG/EAGE salt
  model
• O Summary

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The seismic illumination analysis is a useful
estimate that gives potential detecting power of
a specific acquisition system for a given
structure. Ray tracing based technique Provides
both the intensity and direction information
High efficient Limited by the high frequency
asymptotic approximation Full-wave
finite-difference method Usually provides only
the total illumination Expensive One-way
wave-equation based method Wave-equation
based Local plane wave analysis to provide
direction information 3D full-volume
capability Consistent with the wave equation
based migration/imaging
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Different methods for extracting localized angle
information from migrated wavefields Ray
tracing/Gaussian beam based technique give the
wave propagation direction from the ray
diagram Shot domain common image gather average
direction between the source and the target Plane
source directional source from the
surface Offset-domain one-way wave equation
method Offset plane wave Wavelet transform
based method use wavelet transform to give
information localized in both space and
angle Local plane wave analysis Local plane wave
analysis to provide directional information
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Angle domain analysis for extrapolated wavefields
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Outline

• O Introduction
• O Illumination analysis
• O Directional illumination
• O Acquisition dip-response
• O 3D numerical examples using SEG/EAGE salt
  model
• O Summary

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Illumination analysis using ray based method
(Muerdter 2001)
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Illumination analysis using wave equation based
method
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A sketch showing (a) the directional illumination
(DI) and (b) the acquisition dip-response (ADR).
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Acquisition system
ADR
DI
Favorite target dip
unfavorite target dip
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Outline

• O Introduction
• O Illumination analysis
• O Directional illumination
• O Acquisition dip-response
• O 3D numerical examples using SEG/EAGE salt
  model
• O Summary

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3D SEG/EAGE Salt Model
Locations of surface sources used for DI
calculation, 3600 shots are used to simulate
marine type acquisition
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DI maps for 3D SEG/EAGE Salt Model
V-model
cross sections at y 6100 m
45º left
Vertical
45º right
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3D SEG/EAGE Salt Model
Locations of surface sources. 45 shots are used
to simulate land type acquisition
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3D SEG/EAGE Salt Model, 45 shot data set,
comparisons between the model, total
illumination, and Prestack depth image.
Velocity model
Total illumination
cross sections at x 6000 m
Migration Image (Luo Wu 2003)
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3D SEG/EAGE Salt Model, 45 shot data set,
comparisons between the model, vertical DI,
and Prestack depth image.
Velocity model
vertical illumination
cross sections at x 8600 m
Migration Image (Luo Wu 2003)
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Outline

• O Introduction
• O Illumination analysis
• O Directional illumination
• O Acquisition dip-response
• O 3D numerical examples using SEG/EAGE salt
  model
• O Summary

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30 degree ADR for a single source-cable system
(one shot plus three 3.2 km long cables)
Cross section along the sail direction
Depth slice at 1000 m
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Velocity model
Vertical ADR
Migration Image (Jin et al. 2002)
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Vertical ADR overlay on the prestack image
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Total ADR
Velocity model
Migration Image (Jin et al. 2002)
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Depth f(x,y)
Calculate the illumination on a target zone
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Outline

• O Introduction
• O Illumination analysis
• O Directional illumination
• O Acquisition dip-response
• O 3D numerical examples using SEG/EAGE salt
  model
• O Summary

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Summary O A wave equation based method is
developed for the illumination analysis. The GSP
propagator and local plane wave analysis are used
to extrapolate the wavefield and provide the
directional information. O The method provides
a practical tool to conduct the 3D full-volume
illumination analysis in complex structures. Both
directional illumination (DI) and acquisition
dip-response (ADR) can be generated. The method
can be naturally teamed with the wave equation
based migration method to provide illumination
analysis. O Angle domain information is very
useful. It adds a new dimension for us to look at
the illumination. To demonstrate the potential
applications of this method, preliminary
numerical examples are calculated using the 3D
SEG/EAGE salt model. For more information,
please visit the Modeling and Imaging Lab booth
at 2745.
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