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Transcript of Passive Seismic ImagingSEP/Crustal Research Group [email protected] 1 Return to Passive Imaging...
Passive Seismic ImagingSEP/Crustal Research Group
1
Return to Passive Imaging
Brad Artman
June, 6 2002
Ph.D. Proposal
Passive Seismic ImagingSEP/Crustal Research Group
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State of Affairs
Claerbout’s Conjecture
Terra/Helio-seismology EngineeringExploration
Success
Passive Seismic ImagingSEP/Crustal Research Group
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• The nutshell
• Why it works
• As it stands
• Toward the goal
• How to finish
• When will all this be ready?
Passive Seismic ImagingSEP/Crustal Research Group
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• The nutshellThe nutshell– ProblemProblem– ImportanceImportance– ProposalProposal
• Why it works
• As it stands
• Toward the goal
• How to finish
• When will all this be ready?
Passive Seismic ImagingSEP/Crustal Research Group
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Problem
• Who knows if passive seismic imaging works?– Why (not)?
Passive Seismic ImagingSEP/Crustal Research Group
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Importance
• Lots of people care about the subsurface.
• No source required opens opportunities for:– Monitoring– Reconnaissance– Restricted access sites– Old long data sets– New long data sets
Passive Seismic ImagingSEP/Crustal Research Group
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Proposal
I propose to answer whether or not the passive seismic experiment can be used as a practicable methodology for subsurface imaging and/or monitoring.
+ or - I’ll tell you why.
Passive Seismic ImagingSEP/Crustal Research Group
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• The nutshell
• Why it worksWhy it works– Intuitive explanationIntuitive explanation– Rigorous explanationRigorous explanation
• As it stands
• Toward the goal
• How to finish
• When will all this be ready?
Passive Seismic ImagingSEP/Crustal Research Group
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Intuitive explanation
a
r1 r2 r1*r1 r1*r2
b c
t lag
Passive Seismic ImagingSEP/Crustal Research Group
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Rigorous explanation I
1
U
-RR
Conventional reflection seismic
1
-UU
P
Earthquake seismology
Y –R( ) R(Z) + [1+R( )] [ 1+ R(Z)] = Y U( ) U(Z)Z1
Z1
Z1
1 k
1+R( ) R(Z) = a U( ) U(Z)Z1
Z1
Passive Seismic ImagingSEP/Crustal Research Group
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Rigorous explanation IY –R( ) R(Z) + [1+R( )] [ 1+ R(Z)] = Y U( ) U(Z)Z
1Z1
Z1
1 k
1+R( ) R(Z) = a U( ) U(Z)Z1
Z1
1
U
-RR
Conventional reflection seismic
1
-UU
P
Earthquake seismology
Passive Seismic ImagingSEP/Crustal Research Group
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Intuitive explanation
a
r1 r2 r1*r1 r1*r2
b c
t lag
Passive Seismic ImagingSEP/Crustal Research Group
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Rigorous explanation II
U( ) U(Z) = U(p,ω) U(p,ω) = Q(p,ω)Z1
Q(k,ω) = Q( , ω) = |ω|U(k,ω) U(k,ω)1|ω| ω
k
Q(p,ω) = Q( , ω)ω k
Q(p,ω) = |ω| Q(k,ω)
q(x,t) = (t) u(x’,t) u(x+x’,t+t’)t’x’
rx’,x+x’(t)x’
DFT
Passive Seismic ImagingSEP/Crustal Research Group
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Cross-correlation Technique
Passive Seismic Imaging applied to synthetic data, Rickett SEP-92
Passive Seismic ImagingSEP/Crustal Research Group
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Virtual multiples
a
r1 r2 r1*r1 r1*r2
b c
t lag
Passive Seismic ImagingSEP/Crustal Research Group
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• The nutshell
• Why it works
• As it standsAs it stands– It works!It works!– On the shoulders of giantsOn the shoulders of giants– The raceThe race
• Toward the goal
• How to finish
• When will all this be ready?
Passive Seismic ImagingSEP/Crustal Research Group
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It works!
Acoustic Daylight Imaging via spectral factorization, Rickett SEP-100
Passive Seismic ImagingSEP/Crustal Research Group
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On the shoulders of giants• SEP reports 60 – 86, 100
– SEP’s Franciscan effort and analysis
• Schuster– Correlation migration– Drill bit source
• Bostock– Earthquake array seismograms
• Louie– Engineering characterization
Passive Seismic ImagingSEP/Crustal Research Group
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The Race
• Undisclosed submission
• Company interest
• Livermore???
• The earth from satellite?
Passive Seismic ImagingSEP/Crustal Research Group
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• The nutshell• Why it works• As it stands• Toward the goalToward the goal
– Is 2D possible?Is 2D possible?– Reformulation as migrationReformulation as migration– Motivation to invertMotivation to invert– Sampling the noise-fieldSampling the noise-field– Shape of the noise-fieldShape of the noise-field– Artman GeoServicesArtman GeoServices
• How to finish• When will all this be ready?
Passive Seismic ImagingSEP/Crustal Research Group
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Is 2D possible?
• Yes
• PGS OBC 3C Co-parallel PSD !
Is 2D possible?, Artman, SEP-111
Passive Seismic ImagingSEP/Crustal Research Group
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Reformulation as migrationI(z, x)=Σ P (ω,x,s) P (ω,x,s)
ω
szg
z
P is the wave field at each depth level,where source and receiver fields are propagated independently via SSR.
z
Realization: If P = P , correlation requirement of the passive seismic conjecture
is fulfilled in the migration.
Let the wave equation handle the unknown source.
s g
Passive Seismic ImagingSEP/Crustal Research Group
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Areal Source Wave-fieldShot-profile migration of multiple reflections,Guitton, SEP-111
Passive Seismic ImagingSEP/Crustal Research Group
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Cost Comparison
• Correlations– Spatial increase: N to N (+5 O.M.) – Temporal decrease: N to N (- 4 O.M.)– Migrate (S.P.): N N N N
• Skipping Correlations– No spatial or frequency change: N , N– Migrate (S.P.): N N N N
xy
lag
xy
xy2
xy
t
lag zxy2
t
hxy
t zhxy
Passive Seismic ImagingSEP/Crustal Research Group
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Sampling the noise-field
Minimize storage and processing costsBow to acquisition computer limitations
Passive Seismic ImagingSEP/Crustal Research Group
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• The nutshell
• Why it works
• As it stands
• Toward the goal
• How to finishHow to finish– Brad, the sun, and your coffee tableBrad, the sun, and your coffee table– Santa Clara Valley Seismic ExperimentSanta Clara Valley Seismic Experiment– Recast as deconvolutionRecast as deconvolution– Wave-field separationWave-field separation
• When will all this be ready?
Passive Seismic ImagingSEP/Crustal Research Group
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Solar imaging
• Flare structure, density layering
• Tools: – Absorbing boundary layer modeling– Up-down extrapolator
• James Rickett
Passive Seismic ImagingSEP/Crustal Research Group
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Deconvolution• Who needs physics?
U = T SS = H W
A U = WA = W W H T -1 -1 -1
= H T-1-1
Assume T is white(ish) and events are well spaced-1
Second PEF estimation & application returns T-1
Levinson recursion calculates the reflection coefficients
Passive Seismic ImagingSEP/Crustal Research Group
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Wave-field separation
u = E L R
I
Up-going wave-field
Physics
Surface displacements
E has azimuthal dependency- this may not work.
Passive Seismic ImagingSEP/Crustal Research Group
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Data commitments• Linear acquisition:
– S. California, USGS. Sept. 2002
– S.C. Valley, USGS. Sept. 2002
– 3C OBC, GoM, PGS, June 2002
– Unspecified test, PGS, Sept. 2002
– Publicly available seismologic deployments
• Areal acquisition:– South Texas, CGG, Sept. 2002
– Sun, SOI, in-house
– S.C. Valley, USGS, in-house
– Moss Landing +, Artman GeoServices, in-house
– Publicly available seismologic deployments
Passive Seismic ImagingSEP/Crustal Research Group
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Time-line
• Summer 2002– 3D up-down extrapolator, absorbing BC’s– Image solar flare, submit for publishing– Image Moss Landing beach
• Urban applications?
– Continue collection of outside data– SEG passive seismic workshop
Passive Seismic ImagingSEP/Crustal Research Group
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Time-line
• Fall 2002– Image Santa Clara Valley, submit for publishing– Gather/acquire data– Image data as it arrives– Physics 210: Particle mechanics
Passive Seismic ImagingSEP/Crustal Research Group
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Time-line
• Winter 2002-Spring 2003– Continue data collection and processing– Comp. Sci. 238: Parallel methods in num. analysis– Begin comparative study of successes and failures– Prepare work for publishing
• Summer 2003 – outside internship
Passive Seismic ImagingSEP/Crustal Research Group
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Time-line
• Fall 2003 – Spring 2004– Finalize comparative analysis– Define success parameters– Prepare for publishing
• Summer 2004– Stat. 110: Stat. Methods in eng. and phys. science– Wrap up outstanding projects
Passive Seismic ImagingSEP/Crustal Research Group
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Time-line
• Fall – Winter 2004– PE 284 : Optimization– Write thesis, journal articles
• Spring 2004– Finalize deliverables for graduation