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Reconditioning Seismic Data to Improve Carbonate Stratigraphic Interpretation and Reservoir Characterization, Fullerton Field, West Texas. by Hongliu Zeng Bureau of Economic Geology John A. and Katherine G. Jackson School of Geosciences The University of Texas at Austin. - PowerPoint PPT Presentation
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Reconditioning Seismic Data to Improve Carbonate Stratigraphic Interpretation
and Reservoir Characterization,Fullerton Field, West Texas
by Hongliu ZengBureau of Economic Geology
John A. and Katherine G. Jackson School of GeosciencesThe University of Texas at Austin
Carbonate Earth Mode:How Much Can Seismic Data Help?
Earth ModelSeismic Data
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Presentation Outline
• Value of seismic data as seen in petrophysical analysis• Why seismic data needs reconditioning before
interpretation?• Basic seismic data conditioning (phase adjustment and
high-frequency enhancing)• Advanced seismic data conditioning (progressive, model-
based inversion)
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Fullerton Seismic Data (2-D & 3-D)
Labrador
Southful
Phase 1
Phase 2
2 km
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Synthetic Seismogram (Cal/Mon 1)
Tubb
Abo
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Velocity (ft/s)15000 25000
Porosity0 10 20
De
pth
(ft
)
Ve
loc
ity
(ft
/s)
Porosity
1.2 104
1.4 104
1.6 104
1.8 104
2 104
2.2 104
2.4 104
0 0.05 0.1 0.15 0.2 0.25
y = 20690.30758 - 28524.84397x R= 0.8542726121
6800
6880
6960
7040
7120
7200
7280
7360
Tubb
Wichita
Zone1
Zone2
Abo
Log Velocity vs. Log Porosity(FCU2723)
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Zone 2Zone 1
Wichita
Tubb
Abo
Up. St.
Original Seismic Poorly Tied toLog Lithology/Porosity
DT
1000
1100
ms
1 km
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Basic Data Conditioning
• High-frequency enhancing - Original data are dominated by low frequencies - Boosting high-frequency components improves seismic resolution (even in a price of reducing S/N ratio)
• Adjust seismic phase to 90º- Standard zero-phase wavelet is not ideal for
lithologic interpretation of seismically thin beds - 900-phase data resemble the impedance section, which conditions amplitude to lithology
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
200
300
400
500
600
700
800
900
100
00
Interpretive Advantage of90º-Phase Wavelet(Fullerton Carbonates)
Zone 2
Zone 1
Wichita
Tubb
940
1020
ms
980
1060
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
High-frequency Enhancing(Spectral Balancing)
0 60 120 Hz
Zone 2
Zone 1
Wichita
Tubb
940
1020
ms
980
1060
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Data Conditioning ImprovesResolution and Well-Seismic Tie
Original data
ReconditionedData after phaseShifting and high-Frequency enhancing
Zone 2Zone 1
Wichita
Tubb
Abo
Up. St.
Zone 2Zone 1
Wichita
Tubb
Abo
Up. St.1000
1100
ms
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Amplitude as Indicator of PHIH (L2100/Wichita)
PHIH (well) Amplitude
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
PHIH (well) Amplitude
Amplitude as Indicator of PHIH(L2200/Zone 2)
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Advanced Data Conditioning
• Seismic data are limited in frequency (<100 Hz) and Resolution (10 ms or 100 ft)
• The only source of high-frequency information beyond seismic is well logs
• Use of well logs as soft constrain may significantly improve resolution (2 ms or 20 ft)
• Tool: model-based inversion (Hampson-Russell, Jason, CGG, etc.)
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Model-Based InversionInitial ModelImpedance Logs
SeismicInverted Impedance
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Challenges in Building Initial Model
• Impedance values between wells are interpreted• Correlation of well logs are characterized by
uncertainties of various degrees• Correlation surfaces may not be accurate beyond wells• First initial model is always not optimal
Tubb
Up. St.
Zone1
Zone2
Wichita
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Well Correlation vs. Real Seismic
Tubb
Up. St.
Zone1
Zone2
Wichita
Tubb
Up. St.
Zone1
Zone2
Wichita
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Progressive Inversion
• Build multiple initial models and do multiple inversions• Start from the most prominent and reliable geologic
boundaries and seismic horizons, adding additional horizons from intermediate inversion results
• Use more and more horizons to build better initial model, resulting in better inversion with higher resolution.
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Start from Best Horizons
Tubb
Up. St.
Zone1
Zone2
Wichita
Tubb
Up. St.
Zone1
Zone2
Wichita
Abo
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Progressive Inversion(First Round)
Tubb
Abo
Tubb
Abo
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Tubb
Abo
Tubb
Abo
Progressive Inversion(Second Round)
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Tubb
Abo
Progressive Inversion(Third Round)
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Improvement in Resolution
Seismic 3rd-Round Inversion
100ft
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology
Summary
• Original seismic data are often not optimal for geologic interpretation and need reconditioning
• Basic data conditioning (1) corrects seismic phase and (2) enhance high-frequency components in the data, improving resolution to 100 ft
• Advanced data conditioning combines geologic interpretation and seismic data in a progressive, model-based inversion procedure, further improving resolution to 20 ft
H. Zeng; UL/PTTC May 2003 Workshop, Bureau of Economic Geology