Post on 20-Jan-2016
Crosscorrelation Migration Crosscorrelation Migration of Free-Surface Multiples of Free-Surface Multiples
in CDP Datain CDP Data
Jianming ShengJianming Sheng
University of UtahUniversity of UtahFebruary, 2001February, 2001
OutlineOutline• ObjectiveObjective
• Crosscorrelation migrationCrosscorrelation migration
• Numerical examplesNumerical examples
• SummarySummary
ObjectiveObjectiveTo image free-surface multiplesTo image free-surface multiplesby crosscorrelation migration;by crosscorrelation migration;
To improve the migration imageTo improve the migration imagequality by attenuating the quality by attenuating the artifacts caused by free-surface artifacts caused by free-surface multiples.multiples.
OutlineOutline• ObjectiveObjective
• Crosscorrelation migrationCrosscorrelation migration
• Numerical examplesNumerical examples
• SummarySummary
Principle of CCMPrinciple of CCMG’ GS
X
X’
VIRTUALSOURCE
(CROSSCORRELATION)
G’ GS
X
X’
SOURCE
GG
G’ GS
X
X’
SOURCE
PP
Principle of CCMPrinciple of CCM
xm
Migration imageMigration image
Trial image pointTrial image point
xGxGie '
Imaging ConditionImaging Condition
Asymptotic AnalysisAsymptotic Analysis
xm
xGxGGG '''G
G
S
CrosscorrelogramsCrosscorrelograms
Asymptotic AnalysisAsymptotic Analysis
xmUnder stationary phase conditionUnder stationary phase condition
PPrimaryrimary GGhosthost
Correct imageCorrect image ++ ArtifactsArtifacts
GGhosthost PPrimaryrimary PPrimaryrimaryPPrimaryrimary
GGhosthostGGhosthost3R4R
2R
NegligibleNegligible
Wrong positonWrong positon
Asymptotic AnalysisAsymptotic AnalysisCrosscorrelation migration can Crosscorrelation migration can migrate the multiples to the migrate the multiples to the correct position but generate correct position but generate artifacts as well;artifacts as well;
CCM image alone can not give theCCM image alone can not give thereflectivity distribution!reflectivity distribution!
Key Idea of CCMKey Idea of CCMCCM ImageCCM Image Kirchhoff ImageKirchhoff Image
ReflectorReflector
ArtifactsArtifacts
ArtifactsArtifacts
Key Idea of CCMKey Idea of CCM
Multiplying the Multiplying the two images an two images an improved improved migration migration image can be image can be obtainedobtained
OutlineOutline• ObjectiveObjective
• Crosscorrelation migrationCrosscorrelation migration
• Numerical examplesNumerical examples
• SummarySummary
Numerical ExamplesNumerical Examples
• Three-layered modelThree-layered model
• Nine-layered modelNine-layered model
• SEG/EAGE salt modelSEG/EAGE salt model
Three-Layered ModelThree-Layered Model
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
100 200 300 400 500100 200 300 400 500 100 200 300 400 500100 200 300 400 500
ModelModel CCM ImageCCM Image
Three-Layered ModelThree-Layered Model
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
100 200 300 400 500100 200 300 400 500 100 200 300 400 500100 200 300 400 500
Kirchhoff ImageKirchhoff Image Product ImageProduct Image
Nine-Layered ModelNine-Layered Model
500 1000 1500 2000 2500500 1000 1500 2000 2500
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
24002400
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
24002400
ModelModel CCM imageCCM image
500 1000 1500 2000 2500500 1000 1500 2000 2500
Nine-Layered ModelNine-Layered Model
500 1000 1500 2000 2500500 1000 1500 2000 2500
00
600600
12001200
18001800
30003000
Dep
th (
m)
Dep
th (
m)
24002400
Kirchhoff ImageKirchhoff Image Product ImageProduct Image
500 1000 1500 2000 2500500 1000 1500 2000 2500
SEG/EAGE Salt ModelSEG/EAGE Salt Model
00
600600
12001200
18001800
24002400
Dep
th (
m)
Dep
th (
m)
30003000
36003600
0 5000 10000 150000 5000 10000 15000Distance (m)Distance (m)
320 shots320 shots176 traces per shot176 traces per shot
CCM ImageCCM Image
00
600600
12001200
18001800
24002400
Dep
th (
m)
Dep
th (
m)
30003000
36003600
0 5000 10000 150000 5000 10000 15000Distance (m)Distance (m)
Kirchhoff ImageKirchhoff Image
00
600600
12001200
18001800
24002400
Dep
th (
m)
Dep
th (
m)
30003000
36003600
0 5000 10000 150000 5000 10000 15000Distance (m)Distance (m)
Product ImageProduct Image
00
600600
12001200
18001800
24002400
Dep
th (
m)
Dep
th (
m)
30003000
36003600
0 5000 10000 150000 5000 10000 15000Distance (m)Distance (m)
All right, All right, multiples are migrated, multiples are migrated, … … well, is it useful?well, is it useful?
Yes.Yes.
Kirchhoff ImageKirchhoff Image
00
600600
12001200
18001800
24002400
Dep
th (
m)
Dep
th (
m)
30003000
36003600
0 5000 10000 150000 5000 10000 15000Distance (m)Distance (m)
Product ImageProduct Image
00
600600
12001200
18001800
24002400
Dep
th (
m)
Dep
th (
m)
30003000
36003600
0 5000 10000 150000 5000 10000 15000Distance (m)Distance (m)
OutlineOutline• ObjectiveObjective
• Crosscorrelation migrationCrosscorrelation migration
• Numerical examplesNumerical examples
• SummarySummary
SummarySummary• Multiples can be considered as signal and correctly Multiples can be considered as signal and correctly
imaged by the crosscorrelation migration;imaged by the crosscorrelation migration;
• By multiplying the crosscorrelation and Kirchhoff By multiplying the crosscorrelation and Kirchhoff
migration images, the true reflectors can be migration images, the true reflectors can be
enhanced and the artifacts can be attenuated.enhanced and the artifacts can be attenuated.
Further WorkFurther Work• To attenuate the artifacts generated by To attenuate the artifacts generated by
CCM;CCM;
• To deal with the high-order multiples and To deal with the high-order multiples and
internal multiples.internal multiples.
AcknowledgmentAcknowledgment
I thank the sponsors of the 2000 University I thank the sponsors of the 2000 University of Utah Tomography and Modeling of Utah Tomography and Modeling /Migration (UTAM) Consortium for their /Migration (UTAM) Consortium for their financial support .financial support .