Reverse-Time MigrationReverse-Time MigrationFor 3D SEG/EAGE For 3D SEG/EAGE

Salt ModelSalt Model

Yue WangYue Wang

University of UtahUniversity of Utah

OutlineOutline

• Method & Previous 2D resultsMethod & Previous 2D results

• Result for 3D SEG/EAGE Salt Result for 3D SEG/EAGE Salt ModelModel

• Conclusions & DiscussionsConclusions & Discussions

2-D Salt Model2-D Salt Model

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

2.72.7

00

00 4.54.5

** Geophone LineGeophone LineSourceSource

Shot GatherShot GatherPressurePressureVerticalVerticalHorizontalHorizontal

Tim

e (s

) T

ime

(s)

Distance (km)Distance (km)22

00

0.90.9 3.63.6 Distance (km)Distance (km)0.90.9 3.63.6 Distance (km)Distance (km)0.90.9 3.63.6

PSPS

PPPPReceiver-Side Receiver-Side Surface GhostSurface Ghost

Reversed PhaseReversed Phase

Water bottomWater bottom

How to use P & V?How to use P & V?Key Idea:Key Idea:

• Migrate pressure and particle Migrate pressure and particle velocity velocity simultaneouslysimultaneously by using by using wave-equation;wave-equation;

Up-goingUp-goingWaveWave Down-goingDown-going

Down-goingDown-goingWaveWave

Up-goingUp-going

Kirchhoff MigrationKirchhoff Migration

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

2.52.5

00

0.450.45 4.054.05

Kirchhoff MigrationKirchhoff Migration

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

2.52.5

00

0.450.45 4.054.05

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

2.52.5

00

0.450.45 4.054.05

Particle-Velocity RT SchemeParticle-Velocity RT Scheme

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

2.52.5

00

0.450.45 4.054.05

P & V RT SchemeP & V RT Scheme

OutlineOutline

• Method & Previous 2D resultsMethod & Previous 2D results

• Result for 3D SEG/EAGE Salt Result for 3D SEG/EAGE Salt ModelModel

• Conclusions & DiscussionsConclusions & Discussions

3-D SEG/EAGE Salt Model3-D SEG/EAGE Salt Model

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Ocean-BottomOcean-BottomGeophone LineGeophone Line

Exploding Exploding Reflector SourceReflector Source

CrosslineCrossline

3-D SEG/EAGE Salt Model3-D SEG/EAGE Salt Model

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Ocean-BottomOcean-BottomGeophone LineGeophone Line

Exploding SourceExploding Source

Direct Arrival FromDirect Arrival FromReflection LayerReflection Layer

Ghost ReflectinsGhost Reflectins

3-D SEG/EAGE Salt Model3-D SEG/EAGE Salt Model

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Ocean-BottomOcean-BottomGeophone LineGeophone Line

Exploding SourceExploding Source

3-D SEG/EAGE Salt Model3-D SEG/EAGE Salt Model

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Ocean-BottomOcean-BottomGeophone LineGeophone Line

Exploding SourceExploding Source

Ghost ReflectinsGhost Reflectins

Particle-Velocity RT SchemeParticle-Velocity RT Scheme

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Particle-Velocity RT SchemeParticle-Velocity RT Scheme

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

P & V RT SchemeP & V RT Scheme

Particle-Velocity RT SchemeParticle-Velocity RT Scheme

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

Conclusions & DiscussionsConclusions & Discussions

• Image using both primary and ghost Image using both primary and ghost reflections.reflections.

• FD + kirchhoff hybrid scheme?FD + kirchhoff hybrid scheme?

AcknowledgementAcknowledgement

We are grateful to the 2000 sponsors We are grateful to the 2000 sponsors of the UTAM consortium for the of the UTAM consortium for the financial supportfinancial support

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

P & V SchemeP & V Scheme

Distance (km)Distance (km)

Dep

th (

km

)D

epth

(k

m)

22

00

00 4.54.5

P & V RT SchemeP & V RT Scheme

How to use P & V?How to use P & V?2. Reverse-time migration using P & V:2. Reverse-time migration using P & V:

• Migrate pressure and particle Migrate pressure and particle velocity velocity simultaneouslysimultaneously by using by using wave-equation;wave-equation;

• Ghost is used for imaging;Ghost is used for imaging;• Non-flat water bottom;Non-flat water bottom;• Worked on 2D Model.Worked on 2D Model.