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Acknowledgements Satyan Singh, Jyoti Behura, Roel Snieder Filippo Broggini, Dirk-Jan van Manen Kees Wapenaar, Evert Slob Jan Thorbecke Ivan Vasconcelos Bowen Guo, Jerry Schuster Andrey Bakulin
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Green’s function retrieval by iterative substitution or inversion (?) of the Marchenko equation
Joost van der Neut(Delft University of Technology)
Acknowledgements
Kees Wapenaar, Evert SlobJan Thorbecke
Satyan Singh, Jyoti Behura, Roel Snieder
Ivan Vasconcelos
Filippo Broggini, Dirk-Jan van Manen
Bowen Guo, Jerry Schuster
Andrey Bakulin
Introduction
Input for Marchenko Redatuming
Data Multiple-freeWavelet-freeGhost-freeData
SourceFunction
SurfaceReflectivity
Data
1^^^^ ^
(Van Groenestijn & Verschuur, 2009;Lin and Herrmann, 2013)
EPSI output
Input for Marchenko Redatuming
Data Multiple-freeWavelet-freeGhost-freeData
SourceFunction
SurfaceReflectivity
Data
1
2
Focal point
^^^^ ^
(Van Groenestijn & Verschuur, 2009;Lin and Herrmann, 2013)
EPSI output
BackgroundGreen’s function
Marchenkoredatuming
X
gup
gdown
g0
The aim of Marchenko redatuming
gup gdown
= *
Retrieve e.g. by inversion
Xdatum
Redatuming below a complex overburden
Examples
R T0
Conventional image Marchenko image
Example 1
Example 2
Example 2 – Conventional image
Example 2 – Marchenko image
Model
Target area Image
Example 3 - Conventional
Model
Target area Image
Example 3 – Marchenko(with adaptive subtraction)
Example 4 - ConventionalVelocity Density Image
Red=
without multiples
Yellow=
with multiples
Yellow Red
7000m/s
0 4000kg / m3
0
Example 4 - MarchenkoVelocity Density Image
Red=
without multiples
Yellow=
Marchenko result
Yellow Red
7000m/s
0 4000kg / m3
0
Example 4 with erroneous (constant) velocity - ConventionalVelocity Density Image
Red=
without multiples
Yellow=
with multiples
Yellow Red
7000m/s
0 4000kg / m3
0
Example 4 with erroneous (constant) velocity – MarchenkoVelocity Density Image
Red=
without multiples
Yellow=
Marchenko result
Yellow Red
7000m/s
0 4000kg / m3
0
Example 5 - Sigsbee
Behura et al. (2014)
ConventionalMarchenko
Theory
The focusing function (Wapenaar et al., 2014)
Focal point
Focusing functionResponse Earth
Heterogeneous
The focusing function (Wapenaar et al., 2014)
Focal point
Focusing functionResponse Earth
The focusing function (Wapenaar et al., 2014)
Response
Heterogeneous
Focal point
Focusing functionEarth
Data acting on the focusing function
Reflection response
Heterogeneous
Focal point
Focusing function
Heterogeneous
Time-reversedFocusing function& Green’s function
Representation in matrix-vector notation
Time-reversal Focusingfunction
Green’sfunction
Convolutionwith data
Focusingfunction
Representation in matrix-vector notation
Time-reversal Focusingfunction
Green’sfunction
Convolutionwith data
Focusingfunction
Representation in matrix-vector notation
Time-reversal Focusingfunction
Green’sfunction
Convolutionwith data
Focusingfunction
Unknown Unknown
Exploiting causality
Time-reversedFocusing function
Green’s function
Exploiting causalityWindowfunction
10
Time-reversedFocusing function
Green’s function
Exploiting causality
Windowfunction
Focusingfunction
10
Timereversal
Exploiting causality
10
Windowfunction
Green’sfunction
Exploiting causality
10
01
Windowfunction
BackgroundGreen’s function
Green’sfunction
Green’s function representation
Apply
Intial Green’sfunction (model)
Window Convolutionwith data
Focusingfunction
TimeReversal
Green’s function representation
Apply
Intial Green’sfunction (model)
Window Convolutionwith data
Focusingfunction
TimeReversal
Velocity Density
7000m/s
0 4000kg / m3
0
Retrieved Green’s functions - 1D results from spgl1
Iterative solution(50 iterations)
spgl1 inversion(100 iterations)
Applications for Least-Squares Migration?
Least-Squares Migration
perturbation
Data =
Born approximation
perturbation
Data =
Using Marchenko-based Green’s functions?
perturbation
Data =
Marchenko mapping:
Discussion
Revisiting the problem
1. EPSI (inversion):
2. Focusing functionRetrieval (inversion):
3. Green’s functionRetrieval (forward):
4. Least-SquaresMigration(inversion): δδ