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Product: Prediction of Rock Types– Sand within reservoir intervals– Shale in overlying seal intervals & source intervals

Seismic Stratigraphic Analysis– Define key stratigraphic intervals

– Determine the rock types within each interval

What Is Seismic Facies Analysis?

Input: Seismic Data (2D or 3D)

• Seismic Sequence Analysis

• Seismic Facies Analysis

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Definitions

• Seismic Facies UnitSeismic Facies Unit– a mappable, three dimensional seismic unit

composed of groups of reflections whose parameters differ from those of adjacent facies units.

• Seismic Facies AnalysisSeismic Facies Analysis– the description and geologic interpretation

(environmental setting, lithofacies, etc.) of seismic reflection parameters.

Mitchum et al., 1977a

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Reflection Features Used in Mapping

Feature Significance

ReflectionGeometry

• Depositional Processes

• Bed Thickness• Fluid Content

WaveletFrequency

• Lateral Stratal Continuity• Depositional Processes

ReflectionContinuity

• Impedance Contrasts (significant stratal surfaces)• Bed Spacing / Tuning• Fluid Content

SeismicAmplitude

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Seismic Facies Analysis

Seismic Sequence Analysis

Seismic Facies Analysis

Key Stratigraphic Units Are Broken Out

Interpretation/Prediction

• Patterns are used to Interpret EODs• Lithologies / stacking are predicted

Geometric Relations are Captured through

ABC Mapping

Other Seismic Features are Extracted as

Seismic Attributes

Carbonate Carbonate ShelfShelf

ShelfShelfEdgeEdgeReefReef

Carb.Carb.SlopeSlope

Mitchum et al., 1977bAAPG©1977reprinted with permission of the AAPG whose permission is required for further use.

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Posting Geometric Observation

The ABC Method

A - BA - BCC

A - BA - BCC

A = Termination Pattern at the Upper Sequence Boundary

B = Termination Pattern at the Lower Sequence Boundary

C = Internal Reflection Pattern

Tr = TruncationTp = Toplap C = Concordant

On = OnlapDn = Downlap C = Concordant

p = parallel m = mounded ob = oblique progradationsub = subparallel w = wavy sig = sigmoid progradationdiv = divergent rf = reflection free sh = shingled

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Internal Reflection Patterns

• Parallel• Subparallel• Divergent

Complex

For examples, see AAPG Memoir 26

Stratified

ProgradationalSimple

Unstratified

• Sigmoid• Oblique• Combination• Shingled

• Mounded• Hummocky• Deformed

• Chaotic• Reflection

Free

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Simple Stratified Internal Configurations

Subparallel Divergent

Parallel - Even

Complex

Stratified

ProgradationalSimple

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Progradational Internal Configurations

ObliqueSigmoid

Upbuilding (Aggradation) Outbuilding(Progradation)

Complex

Stratified

ProgradationalSimple

Shingled

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Mounded

Complex Internal Configurations

Hummocky Deformed

Complex

Stratified

ProgradationalSimple

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Line B

The Classic Method - An Example

Each Line is Subdivided into Seismic Facies Unitswhere Each Unit Differs from its Neighbors

Here Facies Units are based on Reflection Geometries

C -On P

T -C Ob

T -Dn Ob

C -Dn P

C -C P

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ABC Codes Posted on a Map

10

30

10 20 30 40 50

40

10 20 30 40 50

Line B

20

Line CLin

e A

T -Dn

Ob

C -On

P

T -C

Ob

C -Dn

P

C -C

P

C -C

P

C -Dn

P

T -Dn

Ob

T -C

Ob

C -On

P

C -C

P

T -C

Div

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Facies Synthesis

10

20

40

30

Line B

Line CL

ine A

10 20 30 40 50

10 20 30 40 50

C -On P

T -C Ob

C -Dn P

C -C P

T -Dn Ob

C -C P

C -Dn P

T -Dn Ob

T -C Ob

C -On P

C -C

PT

-C D

iv

10

20

40

30

Line B

Line CL

ine A

10 20 30 40 50

10 20 30 40 50

C -On P

T -C Ob

C -Dn P

C -C P

T -Dn Ob

C -C P

C -Dn P

T -Dn Ob

T -C Ob

C -On P

C -C

PT

-C D

iv Zone of Progradation

Last

She

lf M

argi

n

30

Line B

Line CL

ine A

10 20

10

C -On P

C -On P

C -C

P

Wedge

C -C P

C -C P

Sheet

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Basin

SlopeMarginalMarine

Non-Marine

Line B

Line CL

ine A

10 20 30 40 50

10 20 30 40 50

10

20

40

30

Depositional Environments

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Inferred Lithology - Prediction

Prediction

Crevasse Splay

Channel Fill

ProximalDistributaryMouth Bar

DistalDistributaryMouth Bar

Prodelta

Delta Front

Facies Model

Delta Front SandstoneDelta Front SiltstonePro-Delta ShalesOffshore Clay

Sea Level

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Time for Another Exercise

Woodbine: Onshore East Texas

Ramsayer, 1979

Line 1Line 1a

OTC©1979 reprinted with permission of the OTC whose permission is required for further use.

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Line 1Well C

Well D

Ramsayer, 1979OTC©1979 reprinted with permission of the OTC whose permission is required for further use.

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ABC-Coded Map

Ramsayer, 1979

Well C

Well D

OTC©1979 reprinted with permission of the OTC whose permission is required for further use.

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C-OnThin

Tp-DnObC-Dn

P

ABC Synthesis

Well C

Well D

Ramsayer, 1979OTC©1979 reprinted with permission of the OTC whose permission is required for further use.

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Interpreted Depositional Environments

Fluvial &Delta Plain

Delta Plain

SlopeDelta

Ramsayer, 1979OTC©1979 reprinted with permission of the OTC whose permission is required for further use.