Overview ofOverview of Utah Tomography and Utah Tomography and

Modeling/MigrationModeling/Migration (UTAM) (UTAM)

Chaiwoot B., T. Crosby, G. Jiang, R. He, G. Schuster, Chaiwoot B., T. Crosby, G. Jiang, R. He, G. Schuster,

J. Sheng, J. Yu, M. Zhou and Xiang Xiao J. Sheng, J. Yu, M. Zhou and Xiang Xiao

2004 UTAM Consortium2004 UTAM ConsortiumAramcoAramco

BP-AmocoBP-Amoco

BGPBGP

GeotomoGeotomo

Chevron-TexacoChevron-Texaco

Conoco-PhillipsConoco-Phillips

IMPIMP

INCOINCO

SisimageSisimage

UnocalUnocal

VeritasVeritas

Western-GecoWestern-Geco

($24 K/year)($24 K/year)

• Started 1988Started 1988

• 10-18 sponsors/year10-18 sponsors/year

• $24,000/year membership$24,000/year membership

• BenefitsBenefits: : Yearly meeting: Feb. 3-4Yearly meeting: Feb. 3-4Annual+midyr ReportAnnual+midyr ReportSoftwareSoftware

• Goal: Innovative Imaging/ModelingGoal: Innovative Imaging/Modeling

UTAMUTAM

Jianhua Yu, Min Zhou

Gerard T. Schuster

University of Utah

Interferometric Imaging below SaltAnd Overburden

Outline Outline

Motivation

Interferometric Imaging

Synthetic Data

Conclusions

Outline Outline

Motivation

Interferometric Imaging

Synthetic & Field Data

Conclusions

Problems with VSP or CDP Salt Problems with VSP or CDP Salt Imaging Quality? Imaging Quality?

Salt v(x,y,z) not knownSalt v(x,y,z) not known

Static errorsStatic errors??

Outline Outline

Motivation

Interferometric Imaging

Synthetic & Field Data

Conclusions

Uninteresting Part of MediumUninteresting Part of Medium

How do you remove kinematic effects of propagatingHow do you remove kinematic effects of propagatingthrough unintersting parts of medium?through unintersting parts of medium?

Pick Direct Arrival Time T and shift allPick Direct Arrival Time T and shift allTraces by T Traces by T MM

MM

{{MMTT

MM

MM

{{MMTT

Shifting Traces Removes Kinematic EffectsShifting Traces Removes Kinematic EffectsOf Propagating through Uninteresting Parts of MediumOf Propagating through Uninteresting Parts of Medium

MM

Shifting Traces Removes Kinematic EffectsShifting Traces Removes Kinematic EffectsOf Propagating through Uninteresting Parts of MediumOf Propagating through Uninteresting Parts of Medium

MM

Shifting Traces Removes Kinematic EffectsShifting Traces Removes Kinematic EffectsOf Propagating through Uninteresting Parts of Medium.Of Propagating through Uninteresting Parts of Medium.

..

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathersSource Moved to DepthSource Moved to Depth

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

Interferometric SummaryInterferometric SummaryEliminates source statics and Eliminates source statics and uninteresting parts of the medium.uninteresting parts of the medium.

Lower source to be near target.Lower source to be near target.

Interferometric SummaryInterferometric SummaryEliminates source+Eliminates source+recrec statics and statics and uninteresting parts of the medium.uninteresting parts of the medium.

Reference layerReference layer

Lower source+Lower source+recrec. to be near target.. to be near target.

Outline Outline

Motivation

Interferometric Imaging

Synthetic CDP Data & Field Data

Conclusions

Shots: 280Shots: 280

Shot interval: 10 mShot interval: 10 m

Receivers: 300Receivers: 300

Receiver interval: 10 mReceiver interval: 10 m

Temporal interval:1msTemporal interval:1ms

X (km)X (km)00 3300

1.81.8

De

pth

(k

m)

De

pth

(k

m)

Salt modelSalt model

X (km)X (km)00 3300

1.81.8

De

pth

(k

m)

De

pth

(k

m)

True velocity modelTrue velocity model

X (km)X (km)00 3300

33

Tim

e (

s)T

ime

(s)

CSG 100CSG 100

Pick TraveltimePick TraveltimeSubsalt ReferenceSubsalt ReferenceReflectionReflection

X (km)X (km)00 3300

1.81.8

De

pth

(k

m)

De

pth

(k

m)

Kirmig with inaccurate salt dome boundaryKirmig with inaccurate salt dome boundary

X (km)X (km)00 3300

1.81.8

De

pth

(k

m)

De

pth

(k

m)

RT migration with inaccurate salt dome RT migration with inaccurate salt dome boundaryboundary

X (km)X (km)00 3300

1.81.8

De

pth

(k

m)

De

pth

(k

m)

Standard migStandard mig

Correct velocityCorrect velocity

X (km)X (km)00 33 X (km)X (km)00 33

Standard migStandard mig

Incorrect Incorrect velocityvelocity

RT migRT mig

Outline Outline

Motivation

Interferometric Imaging

Synthetic HSP Data & Field Data

Conclusions

0 km0 km5 km5 km

0 km0 km

5 km5 km

Mig. Image+Corr. Vel.Mig. Image+Corr. Vel.

0 km0 km

1.2 s1.2 s

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km 1.2 km1.2 km 0 km0 km 1.2 km1.2 km

HSP Shot GatherHSP Shot GatherSalt ModelSalt Model

HSP Interferometric ImagingHSP Interferometric Imaging

0 km0 km5 km5 km

0 km0 km

5 km5 km

Mig. Image+Corr. Vel.Mig. Image+Corr. Vel.

HSP Interferometric ImagingHSP Interferometric Imaging

0 km0 km

1.2 s1.2 s

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km 1.2 km1.2 km 0 km0 km 1.2 km1.2 km

HSP Shot GatherHSP Shot GatherSalt ModelSalt Model

HSP Interferometric ImagingHSP Interferometric Imaging

0 km0 km5 km5 km

0 km0 km

5 km5 km

Mig. Image+Corr. Vel.Mig. Image+Corr. Vel.

0 km0 km

1.2 s1.2 s

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km 1.2 km1.2 km 0 km0 km 1.2 km1.2 km

Salt ModelSalt Model HSP Shot GatherHSP Shot Gather

HSP ImageHSP Image

HSP Interferometric ImagingHSP Interferometric Imaging

0 km0 km5 km5 km

0 km0 km

5 km5 km

Mig. Image+Corr. Vel.Mig. Image+Corr. Vel.

0 km0 km

1.2 s1.2 s

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km 1.2 km1.2 km 0 km0 km 1.2 km1.2 km

Salt ModelSalt Model HSP Shot GatherHSP Shot Gather

HSP ImageHSP Image SWI-HSP ImageSWI-HSP Image

GarbageGarbage

HSP Interferometric ImagingHSP Interferometric Imaging

0 km0 km5 km5 km

0 km0 km

5 km5 km

Mig. Image+Corr. Vel.Mig. Image+Corr. Vel.

0 km0 km

1.2 s1.2 s

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km

1.2 km1.2 km

0 km0 km 1.2 km1.2 km 0 km0 km 1.2 km1.2 km

Salt ModelSalt Model HSP Shot GatherHSP Shot Gather

HSP ImageHSP Image SWI-HSP ImageSWI-HSP Image

GarbageGarbage

No Need for VNo Need for V

HSP Interferometric ImagingHSP Interferometric Imaging

Outline Outline

Motivation

Interferometric Imaging

Synthetic VSP Data & Field Data

Conclusions

VSP DataVSP Data0 km0 km

2 km2 km

0 km 3 km0 km 3 km

Image Below Salt WithoutImage Below Salt WithoutKnowing Salt VelocityKnowing Salt Velocity

X (m) 14001000

950

1950

Dep

th (

m)

Interferometric ImageInterferometric Image

Well

2

0D

epth

(k

m)

0 3X (km)

SEG/EAGE Model

256 Sources

V = 1.5 - 3.0 km/s

Tim

e (s

)

3

00 2.4X (km) 1.4 2.4X (km)

Xcross 60CRG 60

2.0

0.5

Dep

th (

km

)

0.5 2.5X (km)

Kirchh Mig (45) Xcorr Mig (45) Xcorr. Mig(15’)

2.52.5 0.5 0.5

Outline Outline

Motivation

Interferometric Imaging

Synthetic VSP Data & Field Data

Conclusions

Tim

e (s

)

0.3

030 900Depth (ft)

Raw Data(CRG15)

Tim

e (s

)

0.3

030 900Depth (ft)

Ghosts

Dep

th (

ft)

1300

2000 400X (ft) 0 400X (ft)

Standard mig Xcorr. mig

SUMMARYSUMMARY• Interferometric Imaging: Kinematically Interferometric Imaging: Kinematically

equivalent to sources-receivers below datumequivalent to sources-receivers below datum

• Interferometric TomographyInterferometric Tomography

• True wave equation statics w/o V(x,y,z)True wave equation statics w/o V(x,y,z)

• HSP, VSP and CDP dataHSP, VSP and CDP data

Salt + OverburdenSalt + Overburden

SUMMARYSUMMARY• Interferometric Imaging: Kinematically Interferometric Imaging: Kinematically

equivalent to sources-receivers below datumequivalent to sources-receivers below datum

• Interferometric TomographyInterferometric Tomography

• True wave equation statics w/o V(x,y,z)True wave equation statics w/o V(x,y,z)

• HSP, VSP and CDP dataHSP, VSP and CDP data

Salt + OverburdenSalt + Overburden

Crosscorrelogram Migration Conclusions Crosscorrelogram Migration Conclusions

Eliminate the static errors in the well

No need to know source (RVSP) or receiver location (VSP)

Half sensitivity to velocity migration errors than mult. migration by “mirrors”.

Increased illumination coverage in the VSP image. VSP ->CDP

Conclusions Conclusions Loss of some lateral resolution?

Be careful about virtual multiple

Xcorr

Narrow Angle

Kirchhoff

Wide Angle

vs

Ghost is weaker than primaryExtra summation compared to KM

Outline Outline

Motivation

Crosscorrelation Migration

SEG/EAGE Model

2-D RVSP Field Data

Conclusions

Well

2

0D

epth

(k

m)

0 3X (km)

SEG/EAGE Model

256 Sources

V = 1.5 - 3.0 km/s

Well

2

0D

epth

(k

m)

0 3X (km)

Receiver interval: 10 m

Receiver depth range: 0.1 -1 km

Receiver number: 91

Sample interval: 1 ms

Recording length: 3 s

Well location: (1.5 km, 0 km)

Source interval: 10 m

Source number: 256

Acquisition Parameters:

1 km

Tim

e (s

)

3

00.2 0.9Depth (km)

CSG 160

Tim

e (s

)

3

00.2 0.9Depth (km)

Ghosts (CSG 160)

Tim

e (s

)

3

00 2.4X (km) 1.4 2.4X (km)

Xcross 60CRG 60

2.0

0.5

Dep

th (

km

)

0.5 2.5X (km)

Kirchh Mig (45) Xcorr Mig (45) Xcorr. Mig(15’)

2.52.5 0.5 0.5

Sta

tic

erro

rs (

ms)

-50

500 900Well Depth (m)

Raw Data

Static Errors at Well

2.0

0.5

Dep

th (

km

)

0.5

Kirchhoff MigrationStatic Error: 0

X (km)

Static Error: 25 ms

2.5

Static Error: 50ms

2.52.5 0.5 0.5

2.0

0.5

Dep

th (

km

)

0.5

Crosscorrelation MigrationStatic Error: 0

X (km)

Static Error: 25ms

2.5

Static Error: 50 ms

2.52.5 0.5 0.5

Velocity ModelVelocity Model Primary vs Multiple ImagePrimary vs Multiple Image

00

111100 1616 00 1616X (km)X (km) X (km)X (km)

Dep

th (k

m)

Dep

th (k

m)

Contents Contents

Motivation

Crosscorrelation Imaging Condition

SEG/EAGE Model

2-D RVSP Field Data

Conclusions

Tim

e (s

)

0.3

030 900Depth (ft)

Raw Data(CRG15)

Tim

e (s

)

0.3

030 900Depth (ft)

Ghosts

5 24Trace No.

Tim

e (s

)

1.2

0.2 xcorr data (muted)

Tim

e (s

)

1.4

0.55 24Trace No.

Field Data (CSG 25)

Raw data (muted)

Master trace Master trace

Dep

th (

ft)

1300

2000 400X (ft) 0 400X (ft)

Standard mig Xcorr. mig

Dep

th (

ft)

1100

0

Standard Well data Xcorr.

Exxon Data

Outline Outline

Motivation

Crosscorrelation Migration

SEG/EAGE Model

2-D RVSP Field Data

Conclusions

Crosscorrelogram Migration Conclusions Crosscorrelogram Migration Conclusions

Eliminate the static errors in the well

No need to know source (RVSP) or receiver location (VSP)

Half sensitivity to velocity migration errors than mult. migration by “mirrors”.

Increased illumination coverage in the VSP image. VSP ->CDP

Conclusions Conclusions Loss of some lateral resolution?

Be careful about virtual multiple

Xcorr

Narrow Angle

Kirchhoff

Wide Angle

vs

Ghost is weaker than primaryExtra summation compared to KM

AcknowledgmentsAcknowledgments

UTAM sponsorsUTAM sponsors

Exxon for 2-D field dataExxon for 2-D field data

J. Claerbout + J. RickettJ. Claerbout + J. Rickett

II evolved from daylight II evolved from daylight imagingimaging

Dep

th (

ft)

1300

2000 400X (ft) 0 400X (ft)

Standard mig Xcorr. mig

Geological ModelGeological Model0 4

0

3

Dep

th(k

m)

X(km)

(2001)(2001)

Migration Result Using Crosscorrelation ImagingMigration Result Using Crosscorrelation Imaging

1.6

0

2.2

Tim

e (s

)

2.1X (km)

Too simple?

Widen illumination?

If there are static errors in well?

Why Use Crosscorrelation Why Use Crosscorrelation Migration?Migration?

Widen the illumination coverage in the VSP image

VSP geometryEquivalent surface geometry

Xcorr

Seismic Ghost ReflectionSeismic Ghost Reflection

DirectDirect

GhostGhost

??Find R(x,z) but not know source locationFind R(x,z) but not know source location

DirectDirect

GhostGhost

1 2DirectDirect xx

DirectDirectxx

MasterMasterSeismic Ghost ReflectionSeismic Ghost ReflectionSeismic Interferogram: Correlate TracesSeismic Interferogram: Correlate Traces

t}

MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgxMM

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

GhostGhost Direct Direct has kinematics of primary reflectionhas kinematics of primary reflectionxx

MM

WellWell

SourceSource

ReceiverReceiver

Primary

Direct Wave

Ghost

RVSP

x

g

s xg

xg ' sg

'sg

Ghost Reflection Imaging ConditionGhost Reflection Imaging Condition:

'g

xgxgsg

''

sg

'sg

x

g

s xg

xg ' sg

'sg

After Crosscorrelation of Two Traces at After Crosscorrelation of Two Traces at Locations g & g’Locations g & g’

'g

xgxgsg

''

sg

'sg

'sg

x

g

s xg

xg '

After Crosscorrelation of Two Traces at After Crosscorrelation of Two Traces at Locations g & g’Locations g & g’

'g

xgxg

'

sg

'sg

x

g

s

After Crosscorrelation of Two Traces at After Crosscorrelation of Two Traces at Locations g & g’Locations g & g’

'g

xg

xg '

xgxg

'

sg

'sg

Recall Green’s TheoremRecall Green’s TheoremEvery Surface Point = Source PointEvery Surface Point = Source Point

xgxgsgg

''''

Why is there insensitivity to static errors in the well?

ssgsg

'''

xgxgxcorrg

''

s

g’ g

xStatic errors

''sg

xgxgsgg

''''

Crosscorrelogram MigrationCrosscorrelogram Migration

''')( )()( dgdgxgxgggDCorr xm

Migrated ImageMigrated Image

Crosscorrelograms

Crosscorrelation Crosscorrelation Imaging ConditionImaging Condition

Dep

th (

ft)

1100

0

Well data Xcorr. Migration

Field Data

Dep

th (

ft)

1100

0

Well data Standard Migration

Exxon Data

Above SourceAbove SourceImagingImaging {{

Wider CoverageWider Coverage

VSPVSP

Interferometric SummaryInterferometric SummaryWider, taller coverage. Eliminates Wider, taller coverage. Eliminates well statics and uninteresting parts of well statics and uninteresting parts of the medium.the medium.

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

Shifting Traces Removes Kinematic EffectsShifting Traces Removes Kinematic EffectsOf Propagating through Uninteresting Parts of Medium.Of Propagating through Uninteresting Parts of Medium.

..

MM

MM MM

m(x) = (g, t + t )m(x) = (g, t + t )

gxgx gg MMxxgxgx

Kirchhoff Migrate psuedo-shot gathersKirchhoff Migrate psuedo-shot gathers

gg

Source Moved to DepthSource Moved to Depth

Can replace time-shifted traces by crosscorrelogramsCan replace time-shifted traces by crosscorrelograms

m

Distance (km)Distance (km)00 1010

CDP Interferometric Imaging CDP Interferometric Imaging D

epth

(km

)D

epth

(km

)

1010

Distance (km)Distance (km)00 1010

00

Distance (km)Distance (km)00 1010

ModelModelKM image with KM image with

Incorrect velocityIncorrect velocitykm/skm/s

Datuming with Datuming with ReflectionsReflectionss g

3.23.2

3.03.0

2.82.8

m

Distance (km)Distance (km)00 1010

CDP Interferometric Imaging CDP Interferometric Imaging D

epth

(km

)D

epth

(km

)

1010

Distance (km)Distance (km)00 1010

00

Distance (km)Distance (km)00 1010

ModelModelKM image with KM image with

Incorrect velocityIncorrect velocitykm/skm/s

Datuming with Datuming with ReflectionsReflectionss g

3.23.2

3.03.0

2.82.8

m

Distance (km)Distance (km)00 1010

CDP Interferometric Imaging CDP Interferometric Imaging D

epth

(km

)D

epth

(km

)

1010

Distance (km)Distance (km)00 1010

00

Distance (km)Distance (km)00 1010

ModelModelKM image with KM image with

Incorrect velocityIncorrect velocitykm/skm/s

Datuming with Datuming with ReflectionsReflectionss g

3.23.2

3.03.0

2.82.8