5 - seismic attributes & reservoir properties
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7/28/2019 5 - Seismic Attributes & Reservoir Properties
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Seismic Attr ibutes &
Reservoir Properties
Rovicky Dwi Putrohari
COURSE OUTLINE
• Reservoir Model
• Seismic geology Interpretation
• Extracting Stratigraphic from
seismic• Seismic Attr ibutes & Reservoir
Properties
• Reservoir Modeling for ProspectScale
• Exercises
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Seismic Attributes
Seismic attributes may be defined as “all theinformation obtained from seismic data, either bydirect measurements or by logical or experiencebased reasoning.”(Taner, 1998)
•Physical Attribute
– Relate to wave propagation, lithology and otherphysical parameter
•Geometrical Attribute– Geometric attributes describe the spatial and
temporal relationship of all other attributes.
Factor affecting Amplitude
1. Acquisition
2. Processing
3. Post Processing
See Sheriff,
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Factor influencing seismic of sedimentary rocks
Wang, 2001
Well and Seismic Ties
Well data Seismic data
D e p t h
T i m e
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Seismic Trace
*
AI(t) RC(t) W(t) S(t)
WAVELET
Acoustic Impedance Inversion
SeismicAcquisition
Earth * Wavelet = Seismic
Seismic / Wavelet = AI
SeismicInversion
AI Earth
ReservoirModeling/Characterization
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Acoustic impedance Section(Band Limited AI)
- 0 +
Acoustic impedance Section(Final AI)
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Amplitude Section
Impedance Section
LOW
IMPEDANCE
HIGH
IMPEDANCE
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Extracting Attribute
TW Time Horizon Pick
Attr ibute
Extraction
TW Time Horizon Pick
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Extraction
Attr ibute
Display Impedance Section
MAIN
HORIZONS
GR
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Interprete Stratigraphy
TOP SET
TOP SET
TOP SETMAIN
HORIZONS
GR
Define Reservoir Geometry
TOP SET
TOP SET
TOP SET
PARASEQUENCE
GR
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Reservoir Properties from Seismic
Earth Seismic AI Earth
Seismic
Acquis it ion
Earth * Wavelet = Seismic
Seismic / Wavelet = AI
Seismic
Inversion
AI Earth
Reservoir
Modeling
Seismic Modeling
Forward Modeling Inverse Modeling
Input
Process
Output
Earth
Model
Modeling
Algorithm
Seismic
Response
Seismic
Response
Inversion
Algorithm
Earth
Model
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Why use AI ?
• Lithology
• Porosity
• Fluid Content
• Depth
• Pressure (over pressure, AI drops)
Well versus Seismic AI
• Well Acoust ic Impedance :
• AI Log = Density Log x Velocity Log
• Fine vertical sampling
• Seismic Acoustic Impedance :
• Derived by Seismic Inversion
• Good lateral sampling
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AI data can be used as a :
• Lithology Indicator & Map lithology
• Porosity indicator
• Hydrocarbon indicator
• Tool for quantitative analysis
AI and RC
Density (ρ) and velocity (V) :
AI = ρ . V = g/cc . ft/s
AI1
AI2
AI3
RC 1 =
RC 2
AI2 - AI1
AI2 + AI1
- +
RC =Reflection Coefficient
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Amplitude – Acoustic Impedance
Seismic Amplitude
♦ Bondary properties
Acoustic Impedance
♦ Internal propreties
AI on Well
Oil Sand Water Sand
Shale
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AI on SeismicINTERPRETATION PROBLEM
INTERPRETATION PROBLEM AI provide easier (visual) correlat ion/interpretation
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INTERPRETATION PROBLEM AI provide easier (visual) correlat ion/interpretation
Porosity from seismic vs well
Seismic driven porosity profile
Seismic driven porosity map
Well driven porosity profile
Well driven porosity map
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Porosity from seismic and well
Frequency-merged driven porosity profile
Frequency-merged driven porosity map
Porosity from seismic and well
Seismic driven porosity profile
Seismic driven porosity map
Well driven porosity profile
Well driven porosity map
Frequency-merged driven porosity profile
Frequency-merged driven porosity map
Seismic only Well only Well and seismic
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Benefits of Using Acoustic Impedance
• Quantitative predictions of reservoirproperties
• Easier to interpret horizons, faults,stratigraphic units
• Easy to understand by non-geoscientist
• Great integration tool• Compare directly to wells
Quantitative use of AI
• AI can be used to derive rockproperties, such as :
– lithology,
– porosity,
– fluid contents
• Absolute AI can be used for quantitativereservoir characterization
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Seismic
Acquis it ion
Earth * Wavelet = Seismic
Seismic / Wavelet = AI
Seismic
Inversion
AI Earth
Reservoir
Modeling
Reservoir Properties from Seismic
Earth Seismic AI Earth