The Depositional Style(3a)

eddy purnomo 4 unpad bdg

eddy purnomo / 620438jatinangor november 2006


MATERI KULIAH

PENDAHULUANPRINSIP2 DASAR CEKUNGAN SEDIMEN• Cekungan sedimen vs Plate tectonic• Mekanika lithosfer

MEKANISME PEMBENTUKAN CEKUNGAN SEDIMEN• Lithosperic stretching• Flexure• Strike slip deformation

THE SEDIMENTARY BASIN FILL• Faktor pengontrol• Depositional style

EVOLUSI CEKUNGAN SEDIMEN• Subsidence history• Thermal history

APLIKASI DALAM INDUSTRI E & P MIGAS


Cekungan Sedimen vs Plate Tectonic

• Lithospheric Stretching / Divergent Plate Movement : rifting

& passive margin basin

• Lithospheric Flexure / Convergent Plate Movement : foreland

basin, oceanic trench basin

•Transform / Strike Slip Related Basin : pull apart basin

• Cekungan dengan genesa pembentukan yang sama akan

mempunyai kesamaan sejarah pengendapan yang sama



Lingkungan Pengendapan

• Akumulasi dari faktor internal dan eksternal

• Kondisi lingkungan pengendapan tercetak didalam batuan sedimen,

satuan batuan dengan karakter fisik, kimia dan biologi tertentu ~

facies (Steno, 1669)

• Gressly, 1938 ~ facies : satuan batuan dengan karakteristik litologi

dan paleontologi tertentu

• Facies modelling ~ analisis dari data batuan dikaitkan dengan pro-

ses sedimentasi modern

• Profil vertical batuan ~ profil lateral


CEKUNGAN SEDIMEN

• Faktor Autigenic (Tectonic)

• Faktor Allogenic (MAL, Iklim, Organisme)

• Terrestrial – Continental : Fluvial, Aeolian, Lacustrine

• Transitional : Delta – siliciclastic , Coastal – carbonat

& evaporite

• Marine : Shelf (siliciclastic – carbonate) , Deep Marine


CEKUNGAN SEDIMEN



evaporite to siliciclastic



Fluvial System

• Sensitif thd iklim & tektonik (rate of subsidence – up lift – slope)

• Meandering, Braided, Straight & Anastomosed

Braided river : high – variable discharge, steep slope, bed load

Meandering river : stable discharge, low slope, suspended load

Straight river : low – high discharge, steep slope, subsidence>>

Anastomosed river : Stable channel, up lifting >>>






Aeolian System

• Low rainfall, low humidity, fluktuasi temperatur >>, Arid area

• Physical weathering >> chemical weathering

• High energy sandstone (700 meter thick Permian – Jurasic

Navayo sst Utah – Arizona), through X bed

• Gurun (Erg) – Sabkha


Lacustrine System

• Sensitif thd iklim

• Isolated basin

• Chemical – biochemical sediment : organic rich shale,

anhydrite, stromatolitic lst, oolitic – pisolitic grainstone

• Kerogen type – I / oil prone

• Rift basin – pull apart basin

• Laut mati (salinity >>>>)



CEKUNGAN SEDIMEN



evaporite to siliciclastic



Delta System

• Sensitif terhadap pengaruh fluvial & marine

• River dominated delta, wave dominated delta, tidal dominated delta

• Transgressive delta : TAF, Fm Tanjung, Fm Ngimbang

• Regressive delta : Fm Keutapang, ABF, Fm Balikpapan

Fm Tabul – Santul – Tarakan

• Passive margin basin




Coastal System

• Sensitif thd MAL (wave & tidal)

• Siliciclastic – carbonate to evaporite sediment

Siliciclactic Coastal System

• Active tectonic area

Carbonate – evaporite Coatal Syatem

Stable area (relatif)




CEKUNGAN SEDIMEN



evaporite to siliciclactic



Shelf System

• Sensitif thd MAL (wave, tide, oceanic current & storm)

• Siliciclatic – carbonate (platform – reefs)

Siliciclastic shelf system

• Wave, tide, oceanic current & storm dominated shelf

• Tide dominated shelf ~ tidal channel

• Wave dominated shelf ~ clean and coarse sands

• Storm dominated shelf ~ muddy sediment @ innershelf

• Oceanic current dominated shelf ~ longitudinal ribbons

coarse sediment


Shelf System

Carbonate (platform – reefs) shelf system

• Rimmed shelf & open shelf (ramp )

• Rimmed shelf : ideal place for reefs growths (pinacle)

• Open shelf : patch reef (sensitif terhadap wave & tidal

current). Contoh : Arabian shelf

• Reefs ~ organism growth

• Growth stages : Pioneer, Colonization, Diversification

Domination stage

• Keep up, Catch up & give up phase



BARAT TIMUR

BUDIYANI’2000


Deep Marine System

• Slope apron, Submarine fan & Basin plain

• Very fine grain sediment – coarse grain / turbidit

• Low stand system track

• Reservoir ~ thick – v thick

• Source rock

• Seals

• Stratigraphic – structural trap




BASINS RELATED TO DIVERGENT MOTION

• Intra cratonic sags – early rifting basin

• Rift basin

• Failed rift basin

• Passive margin basin


INTRACRATONIC SAGS

• Slow subsidence rate

• No or very weak tectonic activity

• Continental depositional system – shallow marine system

• Siliciclastic (fine – v coarse grain) – shallow carbonate / reefs

anhydrite



RIFT BASIN

• Slow subsidence rate in early phase – rapid subsidence in main rift

• Syn sedimentation structures was developed intensively

• Terrestrial – Lake / Lacustrine in early phase, deltaic sediment in main

rift phase & shallow marine in post rift phase

• Rifting phase followed by volcanic activities

• Fm Talangakar, Fm Balikpapan – Kampungbaru, Fm Tabul – Santul

• Nigerian delta (12.000 meter thick)





NORTHWEST JAVA BASIN

BabadanLow

North CemaraLow

SUB BASIN JATIBARANG

SUB BASIN JATIBARANG

ARJUNA SUB-BASIN

SUB BASINCIPUTAT

B

Sumber data: rekayasa94

A

JAKARTA

CIPUTAT SUB BASINTangerang-Jatinegara

High

PASIR PUTIH SUB BASIN JATIBARANG SUB BASINArjawinangun High Jatibarang Low

Kandanghaur-Gantar High

Cipunegara Low

PamanukanHigh

CilamayaHigh

PasirbungurLow

KepuhLow

RengasdengklokHigh

C i p u ta tLow

CIPUNEGARA LOW

Build-up carbonatParigi

Cisubuh Formation

Basement

Cisubuh Formation Parigi carbonate

build-up

Volkanik Jatibarang

Talangakar Formation

Talangakar

Baturaja

N

Upper Cibulakan

BA

AJW High

TNG-JTN High

Seribu Platform

RDK High

Kepuh Low Pasirbungur

Low

Jatibarang Low

JAVA SEA

SUB CEK. JATIBARANG KEPUH LOW CIPUTAT LOW


BSMNT

TAF

Top BRF

INDEX MAP

Top ParigiTop Parigi

Top Upper CibulakanTop Upper Cibulakan

SWSW NENE

JTB

DATUM TOP TAF

SWSW NENE

CIPUNEGARA LOWCIPUNEGARA LOWPASIR BUNGUR LOWPASIR BUNGUR LOW


FAILED RIFT BASIN ~ AULACOGEN

• Rifting has been aborted before sea floor spreading &

passive margin development

• Miocene rift (western part of Sunda land)

• Generally capped by shallow marine sag sedimen



BSMNT

TAF

Top BRF

INDEX MAP

Top ParigiTop Parigi

Top Upper CibulakanTop Upper Cibulakan

SWSW NENE

JTB

DATUM TOP TAF

SWSW NENE

CIPUNEGARA LOWCIPUNEGARA LOWPASIR BUNGUR LOWPASIR BUNGUR LOW


PASSIVE MARGIN BASIN

• Delta – deep Marine depositional system

• Growth structures (listric normal fault, slumps, slides)

• Shale diapirism

• Prolific petroleum system

• Oil – gas prone source rock

• intraformational shale as a seal

• Rollover listric normal fault





BASINS RELATED TO CONVERGENT MOTION

• Convergent arc related basin : fore arc & back arc

• Foreland basin (peroipheral vs retroarc type)

• Oceanic trench


FORE ARC – BACK ARC BASIN

• Dipisahkan oleh magmatig arc

• Fore arc basin more stable than back arc basin

• Fore arc basin : low heat flow, fine grain sediment – carbonate,

shallow marine / shelf (Sunda land), lean basin except @

siliciclastic Myanmar basin

• Back arc basin : high heat flow, siliciclastic – carbonate, very

prolific basin, terrestrial – deep marine facies




FORELAND BASIN

• Related to the collision zone

• Rapid depositional system : immature sediment,

rapid subsidence, normal fault related

• Terrestrial – deep marine

• Zagros folded belt

• Peripheral vs retroarc type


Critical moment: 250 MaCritical moment: 250 MaPeter & Cassa, 1984)


Geological Cross Section

NW

?

?

Fm. Biak

Fm. Pooh

Ofiolit

?

Tiaka Field

Donggi Field

SE



OCEANIC TRENCH BASIN

• Deep Marine depositional system

• Related to the subductin zone

• Olistrotome - melange sediment

• Basalt, peridotite, chert, pelagic Lst, turbidite etc

• Highly tectonized area

• Less potential for oil & gas



STRIKE SLIP BASIN

• Pull apart basin

• Narrow – deep basin

• Lacustrine – shallow marine

• Rapid facies change

• Non marine sediment at basal sequence and transitional /

shallow marine at the top sequence

• Central Sumatra basin






Samuel & Gultom, 1984

eddy purnomo 4 unpad bdgSamuel and Gultom (1984)


Samuel and Gultom (1984)



TERIMA KASIHTERIMA KASIH

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The Depositional Style(3a)