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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