Sedimentology & Stratigraphic Analysis

• Recognition and Interpretation of Reservoir Types

• Prediction of Reservoir Geometry and Continuity

• Understanding of Controls on Reservoir Quality

• Reservoir Quality Prediction

• Minimize Reservoir Risk

DEPOSITIONAL SYSTEMS INTERPRETATION

SEISMIC FACIES INTERPRETATION

• Basic unit of lithostratigraphic division of rocks is the

formation. Formations may be divided into

member and assembled into group

• Formation should be a ‘body of material which can

be identified by its lithological characteristics and by

its stratigraphic position’. It must be mappable at the

surface or traceable in the subsurface

LITHOSTRATIGRAPHIC HIERARCHY

LINGKUNGAN PENGENDAPAN (LP)

• Adalah keadaan (a natural geo-graphic entity) yang komplek,

yang disebabkan adanya interaksi antara faktor2 kimia, fisika &

biologi dimana sedimen di endapkan (terakumulasi) & keadaan

tsb dapat dibedakan dengan keadaan yang lain. (Krumbein)

• Karena adanya perbedaan, maka masing2 LP dapat untuk

mengidentifikasi media pengendapan, proses (energi fisik)

pergerakan material yang tersedimenkan

1. Lingkungan Continental (lithoral), dng sub lingkungannya adlh lingk

terrestrial (terdiri: endp gurun/ dessert, endapan glacial/ salju) & lingk

aqueous (terdiri: endpn fluvial, paluda, lacustrin, & endpn gua /cave)

2. Lingkungan Transisi, dng sub lingkungannya adlh lingk deltaic, eusta-

rine, lagoonal, litoral /intertidel

3. Lingkungan Laut (marine), dng sub lingkungannya adlh lingk terumbu

karang (reef), neritic, bathyal, dan abysal

BERDASARKAN ASPEK2 f, k & b SECARA KLASIK, ADA 3 KELOMPOK

LINGKUNGAN UTAMA YI:

SILISICLASTIK DEPOSITIONAL SYSTEMS

CONTINENTAL

TRANSITIONAL

MARINE

TERRESTRIAL

AQUEOUS

Desert

Glacial

DeltaicEustarineLagoonalLitoral (intertidal)

ReefNeriticBathyal

Abysal

Fluvial

PaludaLacustrin

Cave

INTERAKSI ANTARA UNSUR2 k, f & b DIMANA

SEDIMEN DI ENDAPKAN, al:

• Material sedimen. Spt; apakah jenis & komposisi batuan sumbernya

• Kondisi pembatasan (boundary condition). Spt; apakah diendapkan jauh/ dekat dari batuan sumber?, apakah peran interaksi yang dominan antara fisik/ mekanis/ kimiawi.?

• Enersi (Mekanis). Spt; apakah mempunyai kondisi tenang-lambat/ keruh-cepat?, enersi rendah/ tinggi?

• Kimia-fisika. Spt a). Apakah diendapkan pd lingkungan pH & Eh tertentu, atau b) Mempunyai kadar garam (salinitas), & konsentrasi kelarutan karbonat tertentu, atau c) kondisi dengan temperatur tertentu.

• Adanya Aktifitas biologi spt: a) struktur pertumbuhan, b) adanya cangkang, c) Material organik (C-H), atau d) adanya struktur galian (burrow).

SEDIMENTARY FACIESProduk/ hasil pengendapan yg di endapkan scr unik di

suatu LP disebut fasies sedimentasi

• Fasies sedimen adalah tubuh batuan sedimen yang

dapat didefinisikan, serta dapat dibedakan dari tubuh

batuan sedimen yang lain dari segi geometri, dan ciri

litologi (fisika, kimia, & biologi) yang sangat khas

• Fasies: merupakan suatu tubuh batuan yang memiliki

kombinasi karakteristik yang khas, dilihat dari litologi,

struktur sedimen & struktur biologi, memperlihatkan

aspek fasies yang berbeda dari tubuh batuan yg ada di

bawah, di atasnya & sekelilingnya (Boggs,1987)

• Fasies umumnya dikelompokan kedalam asosiasi fasies,

dimana fasies2 tsb berhubungan scr genetik shg asosiasi

fasies ini memiliki arti LP (Walker & James, 1922)

• Fasies adalah suatu satuan untuk menunjukan sekumpulan

sifat paleontologis & litologi dari suatu satuan batuan (Steno

1669, Gresely 1938)

• Jumlah total dari atribut2 berskala kecil ini membentuk

satuan batuan tertentu yang berbeda, yang bila digabungkan

disebut fasies

• Fasies Model adalah suatu alat interpretasi yang digunakan

untuk menerangkan asosiasi fasies.

Proses pemodelan fasies adalah fungsi penerangan dengan

mengkaitkan observasi pd proses2 modern & endapan2

purba menjadi suatu sintesa yang koheren

• Keberadaan FM harus:

− Dpt digunakan dlm berbagai cara yg berbeda,

− Hrs menggabungkan banyak data menjadi suatu bentuk yg bersifat umum,

mengenai proses2sedimentasi

− Hrs menjadi stimulan untuk penelitian selanjutnya & berlaku sbg peramal pd

situasi geologis yang baru,

− Hrs membantu memberikan pandangan dlm interpretasi sat sed yg dinamis.

FACIES ANALYSIS

• Facies (from Latin, facia, meaning face or appearance) is lithologic-

al, structural, & organic aspects detectable in the field (de Raaf, 1965)

• Rocks or strata which can be characterized by aspects of their

appearance (lithology, grain size, sedimentary structures, color,

composition, biogenic content)

• It can subdivided into:

• Facies associations constitute several facies that occur in combi-

nation, & typically represent one depositional environment (note that

very few individual facies are diagnostic for one specific setting!)

− Lithofacies (physical & chemical) lithological characteristics of a formation:

sandstone fasies, shale facies

− Biofacies (biological macro/micro-fossil content characteristics of formation:,

shelly facies, crinoidal facies, graptolitic facies, etc

− Ichno facies (trace fossils),

− Also linked with depositional environments-genetic interpretation: shallow

marine facies, fluvial facies, deltaic facies, reef facies, lagoonal facies, etc

(Walker & James)

− Electro facies, Seismic fasies etc

MAJOR FACTOR DEFINE SEDIMENTARY FACIES

BIOTURBATION

FOSSILS

GRAIN SIZE

STRATIFICATION BEDDING

MINENAROLGIFACIES

BIOLOGICAL INDICATOR

HIDRODYNAMIC INDICATOR

LITHOLOGICAL INDICATOR

LITHOFACIES: A rock unit deposited by a unique set of

depositional processesExample: laminated medium-grained quartz sandstone

DEPOSITIONAL ENVIRONMENT: A geomorphic feature where

sediment accumulates:

Examples: shoreface, point bar

FACIES MODEL:

• NORM for Comparison

• GUIDE for Future Work

• PREDICTOR in other successions

• BASIS for Environmental InterpretationsExamples: Meandering stream

Clastic shoreline

A FEW QUICK DEFINITIONS…

• Facies analysis is the interpretation of strata in terms of depositional environments (or depositional systems), commonly based on a wide variety of observations

• Facies models are schematic, three-dimensional representations of specific depositional environments that serve as norms for interpretation and prediction

• Facies models are static in the sense that they focus heavily on autogenic processes and deposits, following Walther’s Law

• Modern processes must constitute the basis for interpreting ancient products (uniformitarianism works in many cases, but not always)

FACIES ANALYSIS

TIPE DASAR SIKLUS

PADA SEDIMEN KLASTIK

1. Penambahan energi transport ke arah atas (diekspresikan

pengkasaran & penebalan lapisan ke arah atas).

2. Penurunan enersi transport, mengekspresikan penghalusan &

penipisan lap ke arah atas

3. Siklus bisa dihasilkan dr proses2 alam di dlm LP (autocyclic)

atau disebabkan oleh kontrol dr luar (allocyclic) LP.

• Tipe mekanisme autocyclic, spt: meandering, avulsion dr river

channel.

• Tipe mekanisme allocyclic, tectonic movement, climatic

variation.

• Mekanisme Autocyclic & allocyclic, penting artinya dlm

pembentukan paket stratigrafi: parasikuen.

High

SE

DIM

EN

T I

NF

LU

X

Low

Slow

SU

BS

IDE

NC

E

Fas

t

Fall

SE

A L

EV

EL

Rise

TRANSGRESSIVE

RETROGRADATION

AGRADATION

PROGRADATION

SEDIMENTATION

• Vertical sikuen dpt diinterpretasikan dr data geophysical, log

sumur. Profil vertikal nampak sbg bentuk yg berbeda GR/SP.

− Upward fining cycles nampak sbg bell shaped log pattern (▲)

− Upward coarsening cycles nampak sbg funnel shaped log

pattern (▼)

− Amalgamated fining & coarsening-up unit sbg symmetrical

− Unit dengan tanpa vertical trend porositas atau kandungan

lempung nampak sebagai cylindrical log pattern.(▐)

FACIES INDIKATOR• Electro Facies

• Sedimentary Facies• Depositional Environment Facies

GENESA & PERKEMBANGAN FACIS MODEL

DIEKSPRESIKAN PADA SIKUEN VERTIKAL

Bentuk profil berdasarkan log adalah

Gamma RayLog

0 150 GAPI

PoreTypes

CorePlugs

LithofaciesCorePetrophysical Data

Capillary

Pressuref vs k

Geological & Petrophysical Data Used to Define Flow Units

FlowUnits

1

2

3

4

5

M IX E D C L E A N D & S H A L LY, N O T R E N D

R O U N D E D B A S E & T O P

A B R U P T B A S E

F -U

A B R U P T T O P

C -UCLEAN, NO TREND

AEOLIAN, BRAIDED FLUVIAL,CARBONATE SHELF,REEF, SUBMARINE CANYON FAN

CREAVASSE SPLAY,DISTRIBUTARY MOUTH BAR,CLASTIC STRAND PALAIN, BARRIERISLAND, SHALLOW MARINE SHEET SANDSTONE,CARBONATE SHOALING UPWARDSEQUENCE, SUBMARINE FAN LOBE

FLUVIAL POINT BAR, TIDAL POINTBAR, DEEP SEA CHANNEL,SOME TRANSGRESSIVE SHELFSANDS

SANDY OFFSHORE BAR SOMETRANSGRESSIVE SHELF SANDS, AMALGAMATEF C-U & F-U UNITS

FLUVIAL FLOODPLAINCARBONATE SLOPE CLASTICSLOPE,CANYON

0 150GAPI 0 150GAPI

0 150GAPI

0 150GAPI

0 150GAPI

LOG PATTERN – LOG FACIES – FACIES of SEDIMENTARYCYLINDRICAL

SHAPE

FUNNEL SHAPE BELL SHAPE SYMMETRICAL

SHAPE

IRREGULAR

SHAPE

Clean, no trend Abrupt top C-U Abrupt base F-U Rounded base & top Mixed cleand &shally, no trend

• Aeolian, • Braided Fluvial, • Carbonate Shelf,• Reef, • Sub-Marine

Canyon Fan

•Fluvial Point Bar•Tidal Point Bar,•Deep Sea Channel•Some Transgressive Shelf Sands

• Creavasse Splay, • Distributary Mouth Bar• Clastic Strand Plain,• Barrier Island,• Shallow Marine Sheet

Sandstone,• Carbonate Shoaling

Upward Sequence, • Sub Marine Fan Lobe

•Sandy Off-shore Bar,•Some Transgressive Shelf Sands,

•Amalgamated C-U & F- U unit

•Fluvial Flood Plain•Carbonat Slope Clastic,

•Slope Canyon

Stratigraphic Architecture &Depositional Environments from

Log Motifs & Stacking Patterns

SPIKYCOARSENING-

UPWARD

FINING-

UPWARD BLOKY

BASIC LOG MOTIF & POSSIBLE INTERPRETATIONS

•Coastal Plain,•Continental Slope

Prograding Shorelines: Channel/ Valley Fill: Channel/Valley Fill:•Deltas

•Strandplains•Fluvial,

•Eustarin,

•Turbidite

•Aggradational

shorelines

0 150 GAPI 0 150 GAPI 0 150 GAPI 0 150 GAPI

Stacking pattern refer to the vertical & lateral arrangement of beds, bedset, Parasequence, parasequences sets, sequences, & sequences sets. These figures ilustrate The Basic Parase-quence Stacking Types & their use in Sequence Stratrigraphic Analysis on simulates GR Logs

0 150 GAPI 0 150 GAPI 0 150 GAPI

SEQUENCE STRATIGRAPHIC ANALYSIS OF WELL LOGS:

BASIC STACKING PATTERNS

Thicker, less shally upwardSediment source moving closer (regrssion)Typical of HIGHSTAND SYSTEMS TRACT

Similar thickness, shalinessSediment source maintained nearbyTypical of LOWSATND SYSTEMS TRACT

Upward thinning, shalierSediment source moving away (transgression)Typical of TRANSGRESSIVE SYSTEMS TRACT

PROGRADATIONALAGGRADATIONAL RETROGRADATIONAL

(Regressive, Seaward-Stepping (Backstepping,Transgressive, Landward-Stepping

Channel Sands Bar, Regressive

Barrier Islands

Sub-marine Channel,

Braided Stream,

Tidal Sands Ridge

Deltaic Couplet:Distributary Channel

Incised into Delta

Front Bar

Vertical variations in grain size to be used in the diagnosis of depositional environment • Fining-upward (F-U), with a scoured base• Coarsening-upward (C-U) profiles• Blocky profiles whereby grain size remains relatively constant• Sands originating in different sub-environments commonly coalesce to

form a single vertical grain-size profile

No single environment has a unique grain-size profile

Similar profiles may be produced by different environments

Therefore, profiles should be interpreted with as much supplementary data as possible.

LB

RU

Alluvial Nearshore Neritic/shelf

GU

GU- Genetic Unit

GALLOWAY.GSS

EXXON 3 Order SB

rd

SB

MFS

SB

MFS

FS

FS

GU Parasequence

SB

RU

RU- Reservoir Unit

GU

FS

FS

FS

FS

Exxon’s sequence boundary (SB)vs Galloway’s genetic stratigraphy(GS)

EXXON’S SEQUENCE BOUNDARY (SB) vs

GALLOWAY’S GENETIC STRATIGRAPHY (GS)

EXXON’S SEQUENCE BOUNDARY (SB) vs

GALLOWAY’S GENETIC STRATIGRAPHY (GS)

MFS-1

MFS-2

MFS-3

SB-1

SB-2

SB-3

MULTIPLE WORKING

HYPOTHESES

RE

GR

ES

SIO

NR

EG

RE

SS

ION

TS

IN

TE

RP

RE

TA

TIO

NI

IN

TE

RP

RE

TA

TIO

N2

TR

AN

GR

ES

SIO

NR

EG

RE

SS

ION

RE

GR

ES

SIO

N

LS

US

F/B

PM

PL

LS

AP

P or

DP

F

PS

US

SB

DEPALEOWATER

DEPTH

DE = Depositional Environment

LS = Lower-Shoreface

US = Upper-ShorefaceF = Fluvial

PM = Paralic Marsh D = Delta Plain

PS = Paralic Swamp B = Beach

AP = Alluvial PlainPL =Paralic Lagoon

Stratigraphic Architecture and Depositional

Environments from Log Motifs and Stacking Patterns

Changes in this arrangement can be used for sequence stratigraphicinterpretation and correlation.

Flooding Surface/Sequence Boundary

Maximum FloodingSurface

IncisedValleySequence

Boundary

Highstand is missing,probably eroded away

Lowstand is missing,probably an interfluve

TST

LST

TST

TST

TST

LST/TST

LST

HST

Sequence Stratigraphic Analysis of Well Logs:Interpretations of Stacking Patterns

Sequence Stratigraphic Analysis of Well Logs:Interpretations of Stacking Patterns

Idealized parasequence stacking patterns of a completedepositional sequence in a shelfal position.

Maximum FloodingSurface

"Transgressive" Surface

Highstand:Progradational

Transgressive:Retrogradational

Lowstand:Aggradational

Highstand:Progradational

Sequence Boundary

Changes in this arrangement can be used for sequence stratigraphicinterpretation and correlation.

Flooding Surface/Sequence Boundary

Maximum FloodingSurface

IncisedValleySequence

Boundary

Highstand is missing,probably eroded away

Lowstand is missing,probably an interfluve

TST

LST

TST

TST

TST

LST/TST

LST

HST

Sequence Stratigraphic Analysis of Well Logs:Interpretations of Stacking Patterns

Sequence Stratigraphic Analysis of Well Logs:Interpretations of Stacking Patterns

Idealized parasequence stacking patterns of a completedepositional sequence in a shelfal position.

Maximum FloodingSurface

"Transgressive" Surface

Highstand:Progradational

Transgressive:Retrogradational

Lowstand:Aggradational

Highstand:Progradational

Sequence Boundary

SUMMARY

• Sequence Stratrigraphy: an integrated framework for

Petroleum Systems Analysis & Predictive models for prospect

generation

• Sequences are controlled by a complex interaction of

tectonism, eustasy, sediment supple & climate

• Several approaches exist, differing mainly in terms of principal

bounding surfaces, one or another may be best for a particular

basin or setting

• From Practices standpoint, we recommend using the most

reasonable & practical approach

C

Distributary Mouth BarD

Shelf Margin DeltaB

Sequence Boundary

Shelf PhaseDelta

UnderlyingSequence

Mass-transportGravity Flows

DistributaryChannels

LowstandShoreline

Emergent Coastal Plain

IncisedFluvialSystem

CoevalDelta Plain

Growth faulting,slumping, sliding

A

B

C

D

E

F

DistributaryMouth Bars

CON-990314.01

LOWSTAND SHELF-MARGIN DELTA DEPOSITIONAL MODELLOWSTAND SHELF-MARGIN DELTA DEPOSITIONAL MODEL

Upper slope / Delta Front Gravity flow deposits

Outer shelf / Upper slope Distal deltaic deposits

IncisedValley Fill

A

Mass-transportgravity flows

Rotationalslumps

E

F

B

E

Shelf Margin Delta

Upper slope / Delta Front Gravity flow depositsDistributary ChannelC

Distributary Mouth BarD

Shelf Margin DeltaB

Sequence Boundary

Shelf PhaseDelta

UnderlyingSequence

Mass-transportGravity Flows

DistributaryChannels

LowstandShoreline

Emergent Coastal Plain

IncisedFluvialSystem

CoevalDelta Plain

Growth faulting,slumping, sliding

A

B

C

D

E

F

DistributaryMouth Bars

CON-990314.01

LOWSTAND SHELF-MARGIN DELTA DEPOSITIONAL MODELLOWSTAND SHELF-MARGIN DELTA DEPOSITIONAL MODEL

Upper slope / Delta Front Gravity flow deposits

Outer shelf / Upper slope Distal deltaic deposits

IncisedValley Fill

A

Mass-transportgravity flows

Rotationalslumps

E

F

B

E

Shelf Margin Delta

Upper slope / Delta Front Gravity flow depositsDistributary Channel