Overview of SEP research

Paul Sava

The problem

dmLModeling operator

Seismic image

Seismic data

Migration

dm *LMigration operator

Seismic image

Seismic data

Migration operator: wavefield propagation

• Downward continuation– Common-azimuth migration– Narrow-azimuth migration

• Reverse time migration

dm *L • Propagation• Imaging• Amplitudes• Velocity

Downward continuation

Narrow-azimuth

Common-azimuth

Biondi, 2003

Reverse-time migrationBiondi & Shan, 2002

Downward-continuation

Reverse-time migration

Migration operator: angle-gathers

• Data-space• Prucha et al

• Image-space• Sava&Fomel, Tisserant&Biondi (S-G)• Rickett&Sava (shot profile)• Rosales&Rickett (converted waves)• Biondi&Shan (reverse-time)

dm *L • Propagation• Imaging• Amplitudes• Velocity

Prucha et. Al (1999), Sava&Fomel (2002)

Angle-domain common image gathers

Data-space ADCIG

Image space ADCIG

3-D angle gathersTisserant & Biondi (2003)

Migration operator: amplitudes

• Amplitude preserving wavefield extrapolation• Sava & Biondi

• Amplitude corrections of extrapolation operators• Vlad et. al

• Hi resolution imaging condition• Valenciano & Biondi

dm *L • Propagation• Imaging• Amplitudes• Velocity

Amplitude-preserving migrationSava & Biondi (2002)

Amplitude preserving

Kinematic migration

Migration operator: velocity

• Traveltime-based• Clapp

• Wavefield-based• Sava & Biondi

dm *L • Propagation• Imaging• Amplitudes• Velocity

Angle-domain traveltime tomographyClapp (2001)

Tomography: geological constraintsClapp (2001)

1 -.4

-.6

Wave-equation MVA

Slowness perturbation

Image perturbation

Sava & Biondi (2003)

z

z

xx

Wave-equation MVASava & Biondi (2003)

Multiple attenuation

• Multiple attenuation– Data space– Image space

• Multiple imaging• Joint imaging

dm *L

2.6

5.

Tim

e (

s)Input data

HyperbolicRadon

Adaptivefiltering

Patternrecognition

Multiple attenuation: data spaceGuitton (2003)

PRT image space

HRT data

space

Multiple attenuation: image spaceSava & Guitton (2003)

Multiple imaging

• Multiple attenuation– Data space– Image space

• Multiple imaging• Joint imaging

dm *L

Multiple imaging: shot-profile migrationGuitton (2002)

Up-goingwavefield

Down-goingwavefield

PrimariesImpulse

Up-goingwavefield

Down-goingwavefield

MultiplesPrimaries

Primaries imaging Multiples imaging

Multiple imaging: S-G migration Shan (2003)

sx sxDx DxUx Uxh x h

1t

2t

2t1R 1R

2R 2R

Joint imaging

• Multiple attenuation– Data space– Image space

• Multiple imaging• Joint imaging

dm *L

Joint imagingBrown (2003)

S G

Migration

dm *LMigration operator

Seismic image

Seismic data

Inversion operator

Least-squares imaging

dm *1* LLL

Seismic image

Seismic data

dm *WL

Least-squares imaging

• Normalized migration• Matching filters• Least-squares inverse• Multiple realizations

• Illumination compensation• Rickett (2001)• Prucha (2003)

Normalized migrationRickett (2003)

dm *BL

Least-squares imagingGuitton (2003)

• Normalized migration• Matching filters• Least-squares inverse• Multiple realizations

(L*L)-1

data

L*

1m L*L

2m

B"" truem

Find B such that

12 mBm

Imaging with mathching filtersGuitton (2003)

Least-squares inverse

dm *1* LLL

• Normalized migration• Matching filters• Least-squares inverse• Multiple realizations

dm *1*2* ε LAALL

Regularization

z-x

preconditioning

z

x

z-ph

preconditioning

z

ph

Prucha (2003)

Regularized inversionPrucha (2003)

Least-squares inverse

Migration

Multiple realizations

dm *1* LLL

• Normalized migration• Matching filters• Least-squares inverse• Multiple realizations

dm *1*2* ε LAALL

0mA0 dmL

Multiple realizations: interpolationClapp (2002)

0mA0 dmL

nmA0 dmL

Multiple realizations: velocityClapp (2002)

http://sepwww.stanford.edu

• Reports (all online)

• Seplib

• Computers: 4 clusters

• 3D real data