Seismic Interferometry
Instead of using just primary
arrivals, you also use the multiples for a wider & more complete view
Gerard Schuster
University of Utah
Overview of Seismic Interferomtery
Short Course
Primary reflections
Multiple reflections
Small
vs
Huge Illumination
Instead of using just primary
arrivals, you also use the multiples for a wider vision
Overview of Seismic Interferomtery
Short Course
Local VSP migration
Redatum sources below overburden
Instead of using just primaryclearer
arrivals, you also use the multiples for a wider vision
Overview of Seismic Interferomtery
Short Course
Data Extrapolation
Instead of using just primaryclearer
arrivals, you also use the multiples for a wider vision
Overview of Seismic Interferomtery
Short Course
Hydrofrac location
Monitoring 4D
Instead of using just primaryclearer
arrivals, you also use the multiples for a wider vision
Goal: Learn Principles and Algorithms in
Seismic Interferometry
Format Mornings: Lecture 50 minutes, followed
by exercise or MATLAB lab.
Format Afternoon: MATLAB labs+discussion.
Topics: Deterministic interferometry, stochastic
interferometry, 3x3 classification matrix,
reciprocity theorems, applications to VSP,
SSP, OBS, and Xwell data.
What is Seismic Interferometry?
Answer: Correlation and summation of trace pairs and
stacking the result for different shot positions
iwtxB
iw(txB+ tBz+ tzB
)
e
e
G(B|x)* G(B|x) =
iw( t Bz+ tzB )
= e
G(B|B)
Point Source Response
with src at B and rec at B
VSP => SSP
B
B
direct
z
reflection
A
x
G(A|B)
Phase of Common Raypath Cancels
Assume a VSP experiment
What is Seismic Interferometry?
Answer: Correlation and summation of trace pairs and
stacking the result for different shot positions
- iwtxB
x
iw(txB+ tBz+ tzB
)
e
e
G(B|x)** G(B|x) =
iw( t Bz+ tzB )
= e
G(B|B)
Point Source Response
with src at A and rec at B
VSP => SSP
B
B
direct
z
x
x
reflection
G(A|B)
A
Phase of Common Raypath Cancels
What is Seismic Interferometry?
Answer: Correlation and summation of trace pairs and
stacking the result for different shot positions
iwtxB
x
iw(txB+ tBz+ tzB
)
e
e
G(B|x)* G(B|x) =
iw( t Bz+ tzB )
= e
G(B|B)
Point Source Response
with src at A and rec at B
VSP => SSP
B
B
direct
z
x
x
reflection
G(A|B)
A
Phase of Common Raypath Cancels
Do Not Need to Know Source Location!
No Need to know Source Initiation Time!
Reciprocity Correlation Equation
2D Reflection Data
x
k =
G(x|B)* G(x|A)
SSP
VSP
VSP
B
G(A|B)
B
A
A
x
x
A
Old Multiples Become
New Primaries!
Phase of Common Raypath Cancels
stellar interferometry, a team of French astronomers has captured one of the sharpest color images ever made. They observed the star T Leporis
with the European Southern Observatory's Very Large Telescope Interferometer (VLTI; Cerro Paranal, Chile), which emulates a virtual telescope
about 100 meters across, and which revealed a spherical molecular shell around the aged star.
Stellar Interferometry
An astronomical interferometer is an array of telescopes or mirror
segments acting together to probe structures with higher resolution.
Standard VSP vs Interferometric VSP Imaging
Standard VSP Imaging
Interferometric VSP Imaging
Primary reflections
Multiple reflections
Small
vs
Huge Illumination
Instead of using just primary
arrivals, you also use the multiples for a wider vision
Interferometry Applications
1. VSP -> SSP :
Small
vs
Huge Illumination
2. VSP -> SWP :
Redatum sources below overburden
Local VSP migration
Interferometry Applications
3. SSP -> SSP :
Interpolation
4. OBS-> OBS :
Extrapolation
5. Source estimation
Interferometry Applications
6. Passive Imaging:
Monitoring 4D
7. Source Location
Monitoring EOR
SELECTIVE HISTORY SEISMIC INTERFEROMETRY
G(A|x)* G(B|x) ~ G(A|B)
!
x
1968
Claerbout V(z)+passive
1980s Cole+Claerbout V(,x,y,z)+passive?
1990s Scherbaum earthquake V(z)+passive
1999
Rickett+Claerbout V(z) Helioseismolgy
Daylight Imaging, passive
2001
Utah Stationary Phase Theory, SSP, and VSP
Seismic Interferomtery, deterministic
2003-04
Wapenaar Recip. Thm. Correlation Type
Shell Virtual Sources
Snieder Stationary Phase Redatuming
Gestoft + others Surface Wave Interferometry