A1260944918SNPWk

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Wave-Equation Migration in Anisotropic Media
Jianhua Yu
University of Utah
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Contents
Motivation
Anisotropic Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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Contents
Motivation
Anisotropic Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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What Blurs Seismic Images?
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Anisotropic Imaging
Ray-based anisotropic migration Anisotropic
velocity model
---Ristow et al, 1998
---Han et al. 2003
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Objective
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Contents
Motivation
Anisotropy Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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General Wave Equation
Wave equation in displacement
Ui displacement component
Cijkl 4th-order stiffness tensor
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Eigensystem Equation
Polarization components of P-P, SV, and SH waves
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Orthorhombic Anisotropic
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Orthorhombic Anisotropic
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Decoupled P plane Wave Motion Equations in (x,z)
and (y,z) planes
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Decoupled P plane Wave Motion Equations in (x,z)
and (y,z) planes
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Dispersion Equations
(x,z) plane
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Thomsens Parameters
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FFD algorithm
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FFD Anisotropy Migration
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How to Set Velocity and Anisotropy Parameters
a b Optimization coefficients of Pade
approximation for FD
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Pade Approximation Comparison
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Error
0
0
90
Angle
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Pade Approximation Comparison
0.05
Beyond 78 within 0.02
Error
0
0
78
Angle
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Contents
Motivation
Anisotropy Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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Strong Anisotropy
Weak Anisotropy
0.6
Kz
0
-0.3
0.3
-0.3
0.3
Kx
Kx
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Dispersion Equation Approximation
0.3
Kz
Strong anisotropy
0
Kx
-0.3
0.3
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0
New
V/V03
iso
Depth (km)
Standard
V/V03
iso
2.0
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0
Strong Aniso
Depth (km)
Weak Aniso
2.0
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Contents
Motivation
Anisotropy Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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X (km)
0
1.5
0
Depth (km)
1
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X (km)
X (km)
0
1.5
0
1.5
0
0
Time (s)
Time (s)
1.2
1
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X (km)
0
1.5
0
Depth (km)
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Isotropic data Isotropic mig (su)
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Contents
Motivation
Anisotropy Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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X (km)
0
5
0
Depth (km)
Salt Model (VTI)
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X (km)
0
5
0
Depth (km)
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Iso-mig
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X (km)
0
5
0
Depth (km)
4
VTI Aniso-mig
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Inaccurate Thomsens Parameters (VTI)
X (km)
0
Depth (km)
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Anisotropy Error 10
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(No Transcript)
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Contents
Motivation
Anisotropy Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE VTI model
3-D SEG/EAGE VTI model
Conclusions
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X (km)
0
5
0
Depth (km)
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VTI Aniso (y1.5 km)
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Y (km)
0
5
0
Depth (km)
VTI Aniso (x1.5 km)
4
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Y (km)
0
5
0
Depth (km)
VTI Aniso (x3 km)
Iso (x3 km)
4
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X (km)
X (km)
0
5
0
5
0
VTI Aniso (z0.5 km)
Y (km)
5
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X (km)
X (km)
0
5
0
5
0
VTI Aniso (z2.5 km)
Y (km)
5
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Contents
Motivation
Anisotropy Wave-Equation Migration
Numerical Examples
Cusp model
2-D SEG/EAGE model
3-D SEG/EAGE model
Conclusions
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Conclusions
o
New gt 78 Anisotropic wave propagator
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Thanks To
2003 UTAM Sponsors
CHPC