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Pre-stack seismic reflection inversion with basis pursuit
Postdoc fellow: Rui Zhang Advisor: Dr. Mrinal Sen and Dr. Sanjay Srinivasan
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Outline
- Motivation
- Formulations
- Synthetic tests
- Field data
- Discussions
- Conclusions
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Pre-stack seismic reflection inversion with basis pursuit Postdoc - - PowerPoint PPT Presentation
Pre-stack seismic reflection inversion with basis pursuit Postdoc - - PowerPoint PPT Presentation
Pre-stack seismic reflection inversion with basis pursuit Postdoc fellow: Rui Zhang Advisor: Dr. Mrinal Sen and Dr. Sanjay Srinivasan 1 Outline Motivation Formulations Synthetic tests Field data Discussions Conclusions
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Motivation
- Post-stack to pre-stack
- Acoustic to elastic
- Improved resolution
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Outline
- Motivation
- Formulations
- Synthetic tests
- Field data
- Discussions
- Conclusions
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Formulations
Aki & Richard
!(#)=1/2 (1+()*↑2 #)∆,↓. /,↓. −4/↑2 /0↑2 12*↑2 #∆,↓1 /,↓1 −[1/2 ()*↑2 #−2/↑2 / 0↑2 12*↑2 #]∆3/3 !(#,()=1/2 (1+()*↑2 #)∆,↓. (()/,↓. (() −4/↑2 /0↑2 12*↑2 #∆,↓1 (()/,↓1 (() −[1/2 ()*↑2 #−2/↑2 /0↑2 12*↑2 #]∆3(()/3(() !↓. (()=∆,↓. (()/,↓. (() !↓1 (()=∆,↓1 (()/,↓1 (() !↓ρ (()=∆ρ(()/ρ(() 5↓. =1/2 (1+()*↑2 #) 5↓1 = -4/↑2 /0↑2 12*↑2 # 5↓ρ =−(1/2 ()*↑2 #−2/↑2 /0↑2 12*↑2 #) //0 is background VsVp ratio
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Formulations
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Even
Wedge reflectivity Wedge seismic response
Odd
=
a + b
Formulations
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Formulations
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Formulations
b A x
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2
min x A b × −
1
min x
Subject to
L1 norm minimization least square solution
] min[
1 2
x x A b λ + × −
Objective Function
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6* ¡,↓( =6*,↓( (0)+∫↑▒9↓( :(
Velocity
,↓( =,↓( (0);↑∫↑▒9↓( :(
Real BPI Conventional
9↓( ¡:
Reflection coefficient
,↓( ¡ : Velocity
Reflection coefficient Velocity
9↓( =∆,↓( /,↓( =∆6*,↓(
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Outline
- Motivation
- Formulations
- Synthetic tests
- Field data
- Discussions
- Conclusions
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1D Synthetic tests
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20% noise
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2D Synthetic tests
Noise free 20% Noise
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2D Synthetic tests
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Outline
- Motivation
- Formulations
- Synthetic tests
- Field data
- Discussions
- Conclusions
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Seismic well “tie”
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Angle dependent wavelets
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Inverted Reflection Coefficients
Pre-stack seismic Inverted Rp Inverted Rs
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Inverted Reflection Coefficients
Post-stack seismic Inverted Rp Inverted Rs
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Inverted Velocity
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Inverted Velocity
Conventional Conventional BPI BPI 23
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3D results
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Discussions
- Perfect processing
- Offset-angle conversion
- Accommodation of non-stationary
- Angle range
- Pre-stack seismic well “tie”
- Initial model
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- Spiky reflectivities Rp and Rs is initial model
independent
- Blocky velocity Vp and Vs is initial model
dependent
- Angle dependent wavelets can stabilize the
results
- Two steps workflow can be QCed twice
- Blocky results enhance layer cake removing side
lobes
Conclusions
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Acknowledgements
- This work supported by Center for Frontiers
- f Subsurface Energy Security , an Energy
Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114
- Dr. Susan D. Hovorka (BEG, GCCC) for
providing data from Cranfield
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