Berita Sedimetologi

7/27/2019 Berita Sedimetologi

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Berita Sedimentologi JAVA

Number 26 May 2013

Published by

The Indonesian Sedimentologists Forum (FOSI)The Sedimentology Commission - The Indonesian Association of Geologists (IAGI)

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Number 26 May 2013

Editorial Board

Herman DarmanChief EditorShell International Exploration and Production B.V.P.O. Box 162, 2501 AN, The HagueThe Netherlands

Fax: +31-70 377 4978E-mail: [email protected]

MinarwanDeputy Chief Editor

Mubadala Petroleum (Thailand) Ltd.31st Floor, Shinawatra Tower 3, 1010 Viphavadi

Rangsit Rd.Chatuchak, Bangkok 10900, ThailandE-mail: [email protected]

Fuad Ahmadin NasutionTotal E&P Indonesie

Jl. Yos Sudarso, Balikpapan 76123

E-mail: [email protected]

Fatrial BahestiPT. Pertamina E&PNAD-North Sumatra AssetsStandard Chartered Building 23rd Floor

Jl Prof Dr Satrio No 164, Jakarta 12950 - IndonesiaE-mail: [email protected]

Wayan Heru YoungUniversity Link coordinatorLegian Kaja, Kuta, Bali 80361, Indonesia

E-mail: [email protected]

Visitasi FemantTreasurerPertamina Hulu EnergiKwarnas Building 6th Floor

Jl. Medan Merdeka Timur No.6, Jakarta 10110E-mail: [email protected]

Rahmat UtomoMubadala Petroleum (Thailand) Ltd.31st Floor, Shinawatra Tower 3, 1010 ViphavadiRangsit Rd.

Chatuchak, Bangkok 10900, ThailandE-mail: [email protected]

Advisory Board

Prof. Yahdi ZaimQuarternary GeologyInstitute of Technology, Bandung

Prof. R. P. KoesoemadinataEmeritus Professor

Institute of Technology, Bandung

Wartono RahardjoUniversity of Gajah Mada, Yogyakarta, Indonesia

Ukat SukantaENI Indonesia

Mohammad SyaifulExploration Think Tank Indonesia

F. Hasan Sidi

Woodside, Perth, Australia

International Reviewers

Prof. Dr. Harry DoustFaculty of Earth and Life Sciences, Vrije UniversiteitDe Boelelaan 10851081 HV Amsterdam, The Netherlands

E-mails: [email protected];[email protected]

Dr. J.T. (Han) van Gorsel6516 Minola St., HOUSTON, TX 77007, USAwww.vangorselslist.comE-mail:[email protected]

Dr. T.J.A. ReijersGeo-Training & TravelGevelakkers 11, 9465TV Anderen, The NetherlandsE-mail:[email protected]

Peter M. Barber PhDPrincipal Sequence StratigrapherIsis Petroleum Consultants P/L

47 Colin Street, West Perth, Western Australia 6005E-mail:[email protected]

Published 3 times a year by the Indonesian Sedimentologists Forum (Forum Sedimentologiwan Indonesia, FOSI), a commission of theIndonesian Association of Geologists (Ikatan Ahli Geologi Indonesia, IAGI).

Cover topics related to sedimentary geology, includes their depositional processes, deformation, minerals, basin fill, etc.

Cover Photograph:

Halang Formation outcrop at

Bantarkawung district, Brebes

Central Java. Taken in 1991.

Photo courtesy of Herman

Darman.
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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Number 26 May 2013

Welcome to Berita Sedimentologinumber 26!

In this edition, Berita

Sedimentologi No. 26/2013, weare focusing on Java Island andits vicinity. Three of the articlesreceived by the editors cover the

eastern part of Java. Edwin andco-authors have submitted apaper on Mundu-PaciranNannofossil zones. A paper on 3D

facies modeling on deepwater fanoutcrop, onshore east Java, wasprepared by Cahyo et al. SuryaNugraha and co-author discussedthe Cenozoic stratigraphy of the

forearc system in the southeast ofJava.

A regional overview of Javasandstone composition wassummarized by Darman et al.

A relatively new research grouphas been established in UPNVeteran Yogyakarta in mid2010. Budiman et al has kindly

provided us an introductionarticle to this group.

The editors have also come upwith general plan for future

themes as the following

BS#27 Sumatra: to bepublished in August 2013

BS#28 Borneo: to be publishedin November 2013

BS#29 SE Asia Biostratigraphyto be published in early 2014

Hopefully with this plan potential

contributors can plan ahead inpreparing their articles.

FOSIs Linked-In group registered

655 members in May 2013. Thedemographics of the group

indicate a good balance betweenthe senior and juniorgeoscientists. The majority of the

members are from oil and gasindustry (78%), followed by themining and metals (15%).

At last on behalf of the editorialteam, I wish you a good readingtime and hopefully you get thebenefit from this bulletin.

Best Regards,

Herman DarmanChief Editor

INSIDE THIS ISSUE

Cenozoic Stratigraphy of the East JavaForearc A. M. S. Nugraha & Robert Hall

5A Case Study on Using Mundu-PaciranNannofossil zones (MPNZ) to SubdivideMundu and Paciran Sequences in the MDAField, East Java Basin, Indonesia A.Edwin et al.

26

Book Review : The SE Asian Getway:History and Tectonic of the Australian-Asia Collision, editor: Robert Hall et alT.J.A. Reijers

56

A Brief History of GeoPangea ResearchGroup A. Budiman et al.

18Short Note : Mineral Composition ofEocene and Miocene Sandstones in JavaIsland H. Darman et al.

33

Book Review - Biodiversity,Biogeography and Nature Conservationin Wallacea and New Guinea (Volume 1),Edited by D. Telnov, Ph.D. H. Darman

58

Three-Dimensional Facies Modeling ofDeepwater Fan Sandbodies: OutcropAnalog Study from the Miocene KerekFormation, Western Kendeng Zone (NorthEast Java Basin) F. A. Cahyo et al.

19

Berita Sedimentologi

A sedimentological Journal of the Indonesia Sedimentologists Forum(FOSI), a commission of the Indonesian Association of Geologist (IAGI)

From the Editor

Call for paperBS #27 Sumatera

to be published in August 2013


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Number 26 May 2013

About FOSI

he forum was founded in1995 as the IndonesianSedimentologists Forum

(FOSI). This organization is acommu-nication and discussion

forum for geologists, especially for

those dealing with sedimentologyand sedimentary geology inIndonesia.

The forum was accepted as thesedimentological commission of

the Indonesian Association ofGeologists (IAGI) in 1996. About300 members were registered in1999, including industrial and

academic fellows, as well asstudents.

FOSI has close internationalrelations with the Society ofSedimentary Geology (SEPM) and

the International Association ofSedimentologists (IAS).

Fellowship is open to those

holding a recognized degree ingeology or a cognate subject andnon-graduates who have at leasttwo years relevant experience.

FOSI has organized 2

international conferences in 1999and 2001, attended by more than150 inter-national participants.

Most of FOSI administrative workwill be handled by the editorial

team. IAGI office in Jakarta willhelp if necessary.

The official website of FOSI is:

http://www.iagi.or.id/fosi/

Any person who has a background in geoscience and/or is engaged in the practising or teaching of geoscienceor its related business may apply for general membership. As the organization has just been restarted, we useLinkedIn (www.linkedin.com) as the main data base platform. We realize that it is not the ideal solution,and we may look for other alternative in the near future. Having said that, for the current situation, LinkedIn

is fit for purpose. International members and students are welcome to join the organization.

T

FOSI Membership

FOSI Group Member

as ofMAY 2013
http://www.iagi.or.id/fosi/http://www.iagi.or.id/fosi/http://www.iagi.or.id/fosi/


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Number 26 May 2013

Cenozoic Stratigraphy of the East Java Forearc

A.M. Surya Nugraha and Robert HallSE Asia Research Group, Department of Earth Sciences, Royal Holloway University of London,Egham, Surrey, TW20 0EX, UK

Corresponding Author: [email protected]

INTRODUCTION

The study area is located in the offshore SE Javaand is situated at the southeast edge of theEurasian plate, known as Sundaland (Figure. 1

and Figure 2). Sundaland is the continental core ofSE Asia and was constructed by amalgamation ofcontinental blocks during the Mesozoic (Hamilton,1979; Metcalfe, 1996; Hall & Morley, 2004).The

East Java Forearc is a relatively unexplored areaand the basement has long been considered to beCretaceous arc and ophiolitic-accretionary

complexes (Hamilton, 1979; Wakita, 2000). But

now there is increasing evidence for continentalcrust beneath the East Java Sea (Manur &Barraclough, 1994; Emmett et al., 2009; Granathet al., 2011), and the southern part of East Java(Smyth, 2005; Smyth et al., 2007, 2008).

This article presents the findings of an MSc study(Nugraha, 2010) and a geological history presented

in an IPA paper (Nugraha & Hall, 2012). Newseismic lines south of Java have imaged a deepstratified sequence which is restricted to East Javaand is absent beneath the West Java forearc. Main

datasets were provided by TGS, comprising threelong-offset 2D-seismic datasets (SJR-9, SJR-10,and SJI-10). These data consist of thirty-seven 2Dmarine seismic lines across the Java forearc with atotal of 8266 km survey length. Previously

published seismic data (Kopp et al., 2006) werelimited to shallow imaging 4-streamer seismic

sections.

All three TGS seismic datasets image down to 9

seconds two-way-time (TWT) and show very deepunits in the forearc basin not seen in previously

published seismic data in the area (Figure 3 andFigure 4). Three well datasets were available,

including: Cilacap-1, Borelis-1, and Alveolina-1.

The Borelis-1 and Alveolina-1 wells were drilled byDjawa Shell N.V. (Bolliger & de Ruiter, 1975) in theearly 1970s and are located in the shallow part of

the offshore Central Java forearc (Figure 2). Thesewells encountered mid-late Cenozoic rocks andhave about 2 km total depth (Figure 5). The

biostratigraphic top information (Shellinterpretations) from these wells form the main

reference for our mid and late Tertiary age-controlled stratigraphic interpretation.

Figure 1. Location of the study area (red box).

Figure 2. Seismic grid used in this study and location of wells.


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REGIONAL STRATIGRAPHY

Subduction and significant arc volcanism ceasedbeneath Java from about 90 Ma to 45 Ma (Hall etal., 2009, Hall, 2009, 2011). Subduction resumed

when Australia began to move northwards in theMiddle Eocene (Hall, 2009). The oldest Cenozoicsediments reported onshore East Java are MiddleEocene (Lelono, 2000, Smyth et al., 2008) and

were deposited unconformably on basement rocks.The Early Cenozoic sandstones above the oldest

sediments increase in volcanic material up-sectionrecording initiation of the Southern Mountain Arc(Smyth, 2005). There is an intra-Oligocene

unconformity across East Java and the East Java

Sea that was mainly caused by sea level change(Matthews & Bransden, 1995; Smyth, 2005).

Explosive volcanic activity was extensivethroughout the Late Oligocene to Early Miocene as

indicated by thick sequences of volcanic andepiclastic rocks (Smyth, 2005; Smyth et al., 2008).The oldest dated sediments exposed in theSouthern Mountains Arc are Oligocene reworked

bioclastic tuffaceous mudstones (Smyth et al.,2008). Upper Oligocene volcaniclastic rocks have

been reported in the Shell Alveolina-1 well,offshore Central Java. In the Borelis-1 well, the

oldest dated rocks are Early Miocene. These twowells terminated in undated basalt (Bolliger & deRuiter, 1975) confirming the presence of SouthernMountain Arc volcanism in offshore South Java.

Figure 3. Approximately N-S seismic line across the East JavaForearc (A) uninterpreted and (B) interpreted, showing maintectonic elements of the forearc and the Lower and Upper

Sections.

Figure 4. Approximately E-W seismic line along the JavaForearc (A) uninterpreted and (B) interpreted, showing thecontrast in structure and stratigraphy of the forearc south of

West and Central Java compared to that south of East Java.The Lower Section is thick south of East Java and dies out closeto a cross-arc high at the position of the Progo-Muria lineament

of Smyth et al. (2005).


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The Early Cenozoic arc volcanism was terminatedby the short-lived Early Miocene Semilir super-

eruption event (Smyth 2005, Smyth et al., 2008,2011). The whole southeast region of Sundalandwas uplifted during this period (Sribudiyani et al.,2005). To the north, a sequence boundary is

placed at the top of the Prupuh Limestone becausebasin inversion is interpreted to have beeninitiated on a regional scale near to the end of itsdeposition in the Middle Miocene (Matthews &Bransden, 1995).

During the Middle Miocene to Late Miocene,

volcanic activity was much reduced. Older volcanicmaterial was reworked and carbonate platformswere developed extensively during this period

(Bolliger & de Ruiter, 1975; Smyth, 2005). Thecarbonates range in age from late Early Miocene to

Middle Miocene (Lokier, 2000; Smyth, 2005).Several tuff beds are observed in turbiditesequences in the Southern Mountains and rangein age from 12 to 10 Ma (Smyth, 2005). This

represents the resumption of volcanic activity atthe position of the present Sunda Arc (Smyth etal., 2005). Lunt et al. (2009) suggested that anunconformity recorded a Late Miocene tectonicevent which created a new series of basins thatwere filled by erosion of structural highs in CentralJava. There are no Pliocene or Quaternary deposits

in the Southern Mountains zone due to uplift anderosion.

Figure 5. Parts of seismiclines that intersect wells

Alveolina-1 and Borelis-1showing seismic unitsidentified in this studyand ages of horizons fromBolliger & de Ruiter

(1975).


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The Shell exploration wells record a major tectonicevent in the Late Pliocene which caused uplift ofJava and the deposition of widespread Plioceneand Quaternary sediments in the offshore area

(Bolliger & de Ruiter, 1975).

STRATIGRAPHIC UNITS

We identify six seismic stratigraphy units, labelledA to F, on the basis of their age, seismic characterand deformation style in combination with onshorepublished studies (Figure 6). We describe these

units from the shallowest to deepest, i.e. from F toA. The ages of Units D to A are reasonablyconstrained by the exploration wells drilled southof Central Java. The ages of Units E and F are

unknown. We consider two possible interpretationsfor the lower section. Unit E shows a half grabencharacter in places suggesting that rifting andextension may be plausibly correlated withSouthern Mountains volcanics and volcaniclastic

deposits on land in East Java (Smyth et al., 2005,2008). Unit F could represent a deeper part of thisarc sequence. To the north of the SouthernMountains lies the thick sequence of the Kendeng

Basin. Thus one possibility is that the thicksequence of Units E and F is equivalent to theMiddle Eocene to Oligocene deposits of theKendeng Basin. An alternative is that Unit F is a

pre-Eocene sequence that was rifted when arcactivity resumed in the Middle Eocene.

Pre-Neogene: Unit F

Unit F is the deepest seismic unit recognizable andit is observed only in the deepest part of theforearc basin (Figure 7). It shows a relatively

uniform ~3 s TWT thickness. The lower part showsmoderate to weak reflectors, while the middle partis characterized by bright and parallel reflectors

with discontinuous lower amplitude reflectors. Theupper part is characterized by chaotic,discontinuous weak amplitude reflectors which arebrighter and relatively parallel near the forearc

basin edges. This unit is cut by a series of planarextensional faults with small displacementsforming graben and half graben structures. Thefaults are more intense in E-W sections along theforearc basin than in N-S sections. A few faults

have been reactivated close to the subductioncomplex and structural highs to the north. Thereare also a few internal thrust faults within thisunit which record later deformation. In places this

unit seems to be truncated by younger units.

Unit F is best imaged beneath the forearc basinwhere the Neogene cover is thin and the structure

is relatively simple, and cannot be mapped atdepths below about 6 sec TWT beneath the forearcflank closer to the Southern Mountains. Although

it not seen Unit F could thicken towards the arc,

where its internal character would be expected tobecome more complex and seismically opaquecloser, since it would be dominated by volcanicrocks rather than the volcaniclastics and

carbonates deposited farther from the active arc.This unit would then form a load-induceddepocentre south of the arc comparable to theKendeng Basin succession and would thicken

towards the arc, although the distribution andthickness of the sequence would influenced byseveral other factors such as the character of theunderlying crust, the width of the forearc and the

dip of the subducting slab. The Kendeng Basin

formed during the Middle Eocene through to EarlyMiocene (de Genevraye & Samuel, 1972; Untung &Sato, 1978; Smyth et al., 2005, 2008) and consistsof terrestrial and shallow marine rocks in a thick

succession that thickens toward the SouthernMountains volcanic arc.

Figure 6. Proposed relations between seismic units of offshore East Java (Alveolina area) and the

stratigraphy of the Southern Mountains Zone on land in East Java (from Smyth et al. 2005, 2008).


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Untung & Sato (1978) suggested that the deeperparts of the basin contain ~6 km of section.

Waltham et al. (2008) used gravity data to suggestan approximate thickness of up to 10 km andproposed that the Kendeng Basin formed by

volcanic arc loading of a broken plate, with acontribution from crustal extension and/or deepcrustal loading. In this interpretation the halfgraben of Unit E would represent extension at a

relatively late stage in the development of theSouthern Mountains arc.

An alternative is that Unit F is older than Middle

Eocene. Deighton et al. (2011) suggested that thisunit could be Mesozoic based on its position andsimilarity of seismic character with Mesozoicand/or Palaeozoic sections from the Australian NWShelf. If the rifting that affects Unit E is Middle

Eocene then Unit F is older. Smyth et al. (2005,2007, 2008) suggested that parts of East Java maybe underlain by a Gondwana fragment derivedfrom western Australia, while a thick cover

sequence of (possibly?) pre-Cenozoic age, identifiedoffshore East Java (Emmett et al., 2009; Granath

et al., 2010), is suggested to have a WestAustralian origin. In the part of the forearc whereUnit F is well imaged it has a relatively constantthickness with sub-parallel reflectors and can be

traced for several hundred kilometres along thelength of the forearc. Internal deformation is

largely restricted to extensional faulting that pre-dates deposition of the forearc basin sequence ofMiocene and younger age. These features are

consistent with a terrestrial to open marinesedimentary sequence deposited on continentalcrust when the East JavaWest Sulawesi fragmentformed part of the Australian margin (Hall et al.,

2009).

This suggestion is supported by the existence ofdeep NW-SE lineaments discussed above. Hall

(2011) suggested that some NW-SE deep structurallineaments, traced across Borneo and intoSulawesi (e.g. Satyana et al. 1999; Fraser et al.2003; Gartrell et al. 2005; Puspita et al. 2005;Simons et al. 2007) represent basement structures

inherited from Australian blocks. Deep and oldstructures can be traced offshore across the NWShelf and Western Australia (e.g. Cadman et al.1993; Goncharov 2004). We suggest that the deep

NW-SE structural lineaments in the East JavaForearc have a Gondwana origin and, based on the

limited evidence available, we prefer to interpretUnit F as a Mesozoic or older section aboveAustralian continental basement.

Figure 7. Approximately N-S seismic line across the East Java Forearc (A) uninterpreted and (B) interpretedshowing seismic units and principal structural features. The deeper reflectors of Unit F are mappable mainlybelow the forearc basin. Note the continuity and broadly constant thickness of seismic reflectors in Unit F

which is cut mainly by extensional faults, except close to the accretionary zone where there are some thrustfaults.


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Pre-Neogene: Units E and D

Unit E is mainly observed in the arc-flank and ischaracterized by parallel discontinuous reflectors

(Figure 8). Wedge geometry is observed withthickening towards faults and is interpreted toindicate sedimentary layers deposited in a syn-riftevent. A series of planar extensional faulted grabenand half graben are observed within this unit along

faults with larger displacements than in Unit F.Several of these faults have been reactivated at thestructural highs. Unit E is interpreted to have been

deposited unconformably above Unit F. In placesclose to the slope break in the forearc flank, Unit Fseems to be truncated by Unit E.

Unit E is tentatively interpreted as alluvial to deltaplain deposits, with higher and lower amplitudesindicating intervals of sand and shale. It issuggested that this sequence was deposited during

rifting in the Middle Eocene. Contemporaneous

clastic sediments in the East Java Sea Basin(Matthews & Bransden, 1995) and Java weredeposited above a regional angular unconformityin a terrestrial to marine environment. In the

Southern Mountains the Middle Eocene NanggulanFormation includes coals, conglomerates, silts andquartz-rich sands (Lelono, 2000; Smyth, 2005;Smyth et al., 2005, 2008).

Unit D was deposited conformably above Unit E .Incontrast with the unit below, Unit D showsgenerally continuous and well bedded strongreflectors with wedge geometry, but does not

clearly thicken towards faults. The seismicreflectors become brighter and more continuousbasinward which suggests a facies change. Unit Cwas probably deposited at the end of the syn-rift

stage. This unit appears to be thinner andtruncated by the base of Unit C near to structuralhighs, and is interpreted to be associated withinversion and erosion. Unit D contains Globigerina

angulisuturalis and Globigerinoides trilobus fossilsfrom wells and has been dated as Late Oligocene(N2-N3) and Middle Early Miocene (N5-N6) above

basalts, volcanic agglomerates, tuffs and clays

(Bolliger & de Ruiter, 1975). Contemporaneousvolcanic deposits crop out in the SouthernMountains Zone and Kendeng Zone (Smyth 2005;

Smyth et al., 2005, 2008).

Figure 8. Approximately N-S seismic line across the forearc flank (A) uninterpreted and (B)interpreted. Units D and E are clearly observed below the Unit C carbonate platform andbuild-u s.


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Middle Miocene Unit C

Unit C shows strong, parallel and fairly continuousreflectors which become variable in amplitudeaway from carbonate buildups. The brightreflectors are interpreted as limestone and thevarying amplitude is interpreted as an alternation

of shelf carbonates and mudstone. The carbonate

buildups tend to be developed on top of structuralor topographic highs (Figure 9). Pinnacle reefs areobserved at the later stage of several carbonate

buildup developments. The unconformity betweenUnits D and C is interpreted to be of Early toMiddle Miocene age. Based on well data andseismic character Unit C is interpreted to comprise

Middle Miocene carbonates equivalent to theonshore Middle Miocene to Lower PlioceneWonosari Formation (Lokier, 1999). The Borelis-1well penetrated the lower part of this unit, dated asLate Middle Miocene based on Globorotalia

siakensis, and the Alveolina-1 well records

carbonate wackestone above (Bolliger & de Ruiter,1975). Unit C is characterized by widespreadcarbonate development above the unconformity,

particularly on structurally high areas associatedwith localized contractional truncation by theunconformity. Progradational cycles are observedwithin the lower part of the carbonates above the

unconformity showing that they were initiallydeposited in lowstands during a period of quiettectonism and much reduced volcanism (Figure10a), and are followed by cycles fromprogradational to retrogradational and/or

aggradational upward (Figure 9). The carbonateplatform is widespread in the western part of thestudy area and decreases to the east.

Upper Miocene Unit B

Unit B is characterized by bright, continuous,alternating reflectors, which are weaker in themiddle part (Figure 11). The upper part of Unit B isobserved to onlap onto the lower part of thecarbonate buildup Unit C (Figure 7). Unit B shows

a relatively constant 0.6-0.8 s TWT thickness

suggesting deposition on the margin slope or outerplatform.

Figure 9. Seismic section crossing carbonate build-up of Unit C in the forearc flank (A)uninterpreted and (B) interpreted. The internal structure of Unit C shows cycles of

progradation, retrogradation and aggradation.


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Figure 10.Palaeogeographic maps

for the East Java forearcbased on this study for

(a) Middle Miocene, (b)Late Miocene to Middle

Pliocene, (c) LatePliocene, and (d) Recent.The entire forearc hassubsided significantlysince the Late Miocene.


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Unit A is interpreted to comprise Pliocenevolcaniclastics and deep marine clays, sometimes

interbedded with calci-turbidites (Bolliger & deRuiter, 1975). In the forearc basin, Unit A ischaracterized by a wedge shape, tilted landwards,with a number of local unconformities that record

the episodic uplift of the outer arc ridges (Figure11). These sequences onlap and downlap onto UnitB. Mass transport-slump complexes observed inthis unit reflect submarine slope failure associatedwith uplift of the outer-arc high above the

subduction zone. Further north canyons incise

Unit A; some are infilled whereas others are activeat the present-day (Fig 13). The high rates andwidespread sedimentation could be related to

resumption of volcanic activity in the modern JavaArc.

CONCLUSIONS

New seismic data allow the East Java forearc to bedivided into six major seismic units bounded bythree major unconformities. We suggest that thedeepest, Unit F, may represent a pre-Cenozoicsequence deposited on continental crust, derived

from Western Australia. A major regionalunconformity separates this from a Middle Eoceneto Lower Miocene sequence (Units E and D)equivalent to the Southern Mountains volcanic arc

and Kendeng Basin deposits of East Java.

Extensive shallow water carbonates (Unit C) weredeposited above a LowerMiddle Mioceneunconformity during a tectonically quiet period

with much reduced volcanism in the northern partof the present forearc. Major changes in the forearcbegan in the Late Miocene.

Figure 12. Seismic section showing units at the southern boundary of the forearc basin withthe outer-arc slope east of Figure 9 (A) uninterpreted and (B) interpreted. The forearc basin in

this area here is largely filled with Pliocene sediments of Unit A. Note that Unit B is thinnertowards the forearc basin depocentre.


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There was significant subsidence (Unit B) withdrowning of the former carbonate platforms. Weinterpret deformation at the southern side of theforearc to be caused by arrival of a buoyant

plateau at the subduction margin producing aregional unconformity that can be mapped acrossthe whole East Java forearc. Afterwards, olderrocks were buried by Late Pliocene volcanogenic

deposits (Unit A) with high rates of sedimentation.

ACKNOWLEDGEMENTS

We thank TGS for providing the data, the

consortium of oil companies who support the SE

Asia Research Group for funding the MSc study ofA.M. Surya Nugraha, and Chris Elders, IanDeighton and Simon Suggate for advice and help.

REFERENCES

Audley-Charles, M.G., 1983, Reconstruction ofeastern Gondwanaland: Nature, v. 306, p. 48-

50.Bolliger, W., and de Ruiter, P.A.C., 1975, Geology

of the South Central Java Offshore Area:Indonesian Petroleum Association, Proceedings4th annual convention, Jakarta, 1975, v. I, p.

67-82.Cadman, S.J., Pain, L., Vuckovic, V., and le

Poidevin, S.R., 1993 Canning Basin, W.A. ,Bureau of Resource Sciences, Australian

Petroleum Accumulations Report Volume 9.

de Genevraye, P., and Samuel, L., 1972, Thegeology of Kendeng Zone (East Java):Indonesian Petroleum Association, Proceedings

1st annual convention, Jakarta, 1972, p. 17-30.Deighton, I., Hancock, T., Hudson, G., Tamannai,

M., Conn, P., and Oh, K., 2011, Infill seismic in

Figure 13. Cross section across one of the present-day submarine canyons in the outer

part of the forearc flank (A) uninterpreted and (B) interpreted. The stepped profile of thecanyon margin suggests that repeated cut and fill has taken place. There are severalinactive canyons which has been filled and buried by later sediment.


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the southeast Java Forearc Basin: Implicationsfor Petroleum Prospectivity: ProceedingsIndonesian Petroleum Association, 35th AnnualConvention, p. IPA11-G-068.

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Fold Belt and other new plays within the NorthMakassar Straits - a Prospectivity Review,Indonesian Petroleum Association, Proceedings29th Annual Convention, Volume 1: Jakarta, p.

431-450.Gartrell, A., Hudson, C., and Evans, B., 2005, The

influence on basement faults during extension

and oblique inversion of the Makassar Straits

rift system: Insights from analog models: AAPGBulletin, v. 89, p. 495-506.

Goncharov, A., 2004, Basement and crustalstructure of the Bonaparte and Browse basins,

Australian northwest margin, in Ellis, G.K.,Baillie, P., and Munson, T.J., eds., Proceedingsof the Timor Sea Symposium, Volume SpecialPublication 1: Darwin Northern Territory,

Australia, Northern Territory Geological Survey.Granath, J.W., Christ, J.M., Emmet, P.A., and

Dinkelman, M.G., 2011, Pre-Cenozoicsedimentary section and structure as reflected

in the JavaSPAN crustal-scale PSDM seismic

survey, and its implications regarding thebasement terranes in the East Java Sea in Hall,R., Cottam, M.A., and Wilson, M.E.J., eds., TheSE Asian Gateway: History and Tectonics of the

Australia-Asia collision, Volume 355: GeologicalSociety of London Special Publication, p. 53-74.

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Geological Society of London SpecialPublication, p. 351-372.

Hall, R., 2011, Australia-SE Asia collision: platetectonics and crustal flow, in Hall, R., Cottam,

M.A., and Wilson, M.E.J., eds., The SE AsianGateway: History and Tectonics of theAustralia-Asia collision, Volume 355: GeologicalSociety of London Special Publication, p. 75-109.

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Sundaland: Basement character, structure andplate tectonic development: ProceedingsIndonesian Petroleum Association, 33rd Annual

Convention.

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Hamilton, W., 1988, Plate tectonics and island

arcs: Geological Society of America Bulletin, v.100, p. 1503-1527.

Kopp, H., 2011, The Java convergent margin:structure, seismogenesis and subductionprocesses, in Hall, R., Cottam, M.A., and

Wilson, M.E.J., eds., The SE Asian Gateway:History and Tectonics of the Australia-Asiacollision, Volume 355: Geological Society ofLondon Special Publication, p. 111-137.

Kopp, H., Flueh, E.R., Petersen, C.J., Weinrebe,W., Wittwer, A., and Scientists, M., 2006, TheJava margin revisited: Evidence for subductionerosion off Java: Earth and Planetary Science

Letters, v. 242, p. 130-142.Lelono, E.B., 2000, Palynological study of the

Eocene Nanggulan Formation, Central Java,

Indonesia [Ph.D. thesis], University of London.

Lokier, S.W., 2000, The development of theMiocene Wonosari Formation, south CentralJava: Indonesian Petroleum Association,Proceedings 27th Annual Convention, Jakarta,

2000, v. 1, p. 217-222.Lunt, P., Burgon, G., and Baky, A., 2009, The

Pemali Formation of Central Java andequivalents: Indicators of sedimentation on an

active plate margin: Journal of Asian EarthSciences, v. 34 p. 100-113.

Macpherson, C.G., and Hall, R., 1999, Tectoniccontrols of Geochemical Evolution in Arc

Magmatism of SE Asia, Proceedings 4th

PACRIM Congress 1999: Bali, Indonesia,Australian Institute of Mining and Metallurgy,p. 359-368.

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tectonic controls on magmatism and oregeneration in an evolving orogen: evidence from

Southeast Asia and the western Pacific, inBlundell, D.J., Neubauer, F., and von Quadt,A., eds., The timing and location of major oredeposits in an evolving orogen, Volume 204:Geological Society of London Special

Publication, Geological Society of LondonSpecial Publication, p. 49-67.

Manur, H., and Barraclough, R., 1994, Structuralcontrol on hydrocarbon habitat in the Bawean

area, East Java Sea: Indonesian PetroleumAssociation, Proceedings 23rd annualconvention, Jakarta, 1994, v. 1, p. 129-144.

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G.J., Sikumbang, N., Dwiwanto, B., andKallagher, H., 1990, Subduction of seamountsat the Java Trench; a view with long range side-scan sonar: Tectonophysics, v. 185, p. 51-65.

Matthews, S.J., and Bransden, P.J.E., 1995, Late

Cretaceous and Cenozoic tectono-stratigraphic

development of the East Java Sea Basin,Indonesia: Marine and Petroleum Geology, v.12, p. 499-510.

Nugraha, A.M.S., 2011, Tectono-stratigraphicEvolution of the East Java Forearc, Indonesia:


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MSc Thesis. London, Royal Holloway Universityof London.

Nugraha, A.M.S., and Hall, R., 2012, CenozoicHistory of the East Java Forearc: Indonesian

Petroleum Association, Proceedings 36thAnnual Convention.

Puspita, S.D., Hall, R., and Elders, C.F., 2005,Structural styles of the Offshore West SulawesiFold Belt, North Makassar Straits, Indonesia:

Indonesian Petroleum Association, Proceedings30th Annual Convention, p. 519-542.

Satyana, A.H., Nugroho, D., and Surantoko, I.,1999, Tectonic controls on the hydrocarbon

habitats of the Barito, Kutei, and TarakanBasins, eastern Kalimantan, Indonesia: majordissimilarities in adjoining basins: Journal ofAsian Earth Sciences, v. 17, p. 99-122.

Seubert, B.W., and Sulistianingsih, F., 2008, Aproposed new model for the tectonic evolution ofSouth Java, Indonesia, Proceedings Indonesian

Petroleum Association 32nd Annual

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Planert, L., Engels, M., Flueh, E.R.,Krabbenhoeft, A., and Djajadihardja, Y., 2009,

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Smyth, H., Hall, R., Hamilton, J., and Kinny, P.,2005, East Java: Cenozoic basins, volcanoes

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Smyth, H.R., 2005, Eocene to Miocene basinhistory and volcanic history in East Java,Indonesia [Ph.D. thesis], University of London.

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Cenozoic volcanic arc history of East Java,Indonesia: the stratigraphic record of eruptionson an active continental margin, in Draut, A.E.,Clift, P.D., and Scholl, D.W., eds., Formationand Applications of the Sedimentary Record in

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A Brief History of GeoPangea Research Group

Agung Budiman, Iqbal Fardiansyah and Leon TaufaniGeoPangea Research Group (GPRG) IndonesiaCorresponding Author: [email protected]

INTRODUCTION

GeoPangea Research Group (GPRG) is an

independent research group founded on May 31st,2010, led by ideas from young and passionategeology students of UPN Veteran Yogyakarta. The

group is supervised by Dr. C. Prasetyadi, a facultymember of the Geology Department, as well as amentor to all research-related activities conductedby GPRG. This group aims to contribute to

scientific knowledge in numerous aspects ofgeosciences (i.e. regional geology, sedimentologyand stratigraphy, structural geology, tectonics,

etc.) by performing research and demonstrating

their application in hydrocarbon exploration. Theresults of our research are documented aspublished papers and articles in various journals

and scientific conferences of both regional andinternational levels.

GPRG RESEARCH FOCUS

The focus area of GPRG is primarily on field and

experimental-based research (Figures 1 and 2). Todate, there are more than twenty professionalpapers and articles that have been published by

GPRG, with the first research conducted in late2010, entitled: Sedimentology of ParangtritisCoastal Dunes and Stream Table Analogue forFluvial-Deltaic Morphology (Figure 2a). Since then,

this group keeps consistently developingexperimental sed-strat analyses and structuralanalogue modeling within the loop of research

projects (Figures 2b and 2c). GPRG currently

employs eight professional researchers and sixundergraduate students of UPN VeteranYogyakarta. Research projects are internally

funded by the members monthly dues andsupported by the laboratory facilities of the

Geology Department, UPN Veteran Yogyakarta.Any questions/interests related to our researchgroup can be addressed to us via the website :

www.gprgindonesia.wordpress.com.

Figure 1. Some photos of GPRGs field workactivities. (a) and (b) outcrop observations ; (c)and (d) example of modern sedimentological

study of lagoonal deposits.

Figure 2. Experimental-based research of GPRG,which is facilitated by laboratories of the Geology

Department, UPN Veteran Yogyakarta. (a)Stream table analogue for fluvio- deltaic

morphology (2010) ; (b) Flume tank modeling toreconstruct chronostratigraphy within growth-faulted delta system (2011) ; and (c) Sandbox

analogue for structural kinematics and geometry

identification (2012).
http://www.gprgindonesia.wordpress.com/http://www.gprgindonesia.wordpress.com/http://www.gprgindonesia.wordpress.com/


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Three-Dimensional Facies Modeling of Deepwater FanSandbodies: Outcrop Analog Study from the Miocene KerekFormation, Western Kendeng Zone (North East Java Basin)

Ferry Andika Cahyo1,2, Octavika Malda2, Iqbal Fardiansyah2 and Carolus Prasetyadi1

1Department of Geology UPN Veteran Yogyakarta2GeoPangea Research Group (GPRG)

Corresponding Author: [email protected], [email protected]

ABSTRACT

Kendeng Zone is well known as the main depocenter in the North East Java Basin. It developed asa back arc basin related to Oligo-Miocene volcanic arc and was subsequently filled with thick

pelagic and volcanogenic sediments.

This article emphasizes on determination of facies, geometry and distribution of sand bodies withinthe Miocene Kerek Formation that comprises the western Kendeng Zone. Sedimentological logs androck samples were collected from outcrop data along river traverses in the study area. The samples

were described and characterized by using petrography, paleontology and sedimentology analyses.Three depositional facies were identified, which consist of massive sandstone of submarine lower

fan, a lobe of submarine lower fan and pelagic mud deposits.

Statistical analysis was also used to characterize and describe identified depositional facies withinthe Kerek Formation. Statistically, the geometry consists of (1) pebbly massive sandstones ofsubmarine lower fan (mean distribution of sands bodies: 4.58 km, mean thickness: 0.6 m, length

from 3D modeling: 1.58 km); (2) sandstone sheets of submarine lower fan (mean distribution of

sands bodies: 2.85 km, mean thickness: 0.08 m, length from 3D fence diagram: 1.26 km); (3) pelagicmud, which is composed solely of thick mudstone lithofacies. In term of reservoir potential, themassive sandstones that have significant amount of porosity would be considered as having the

highest potential.

INTRODUCTION

The study area is located in Kedungjati region,Purwodadi, Central Java (Figure 1).Stratigraphically, the area is comprised of fourlithologic units (formations) that include (in

younger order) Calcareous-sandstone of KerekFormation, Tuffaceous-sandstone of BanyakMember (Kalibeng Formation), Calcareous-claystone of Kalibeng Formation and Limestone of

Kapung Member (Kalibeng Formation) (Figure 2).

North East Java basin, particularly the KendengZone, is located between volcanic arcs at present.

The Kendeng Zone was the main depocenter forEocene-Miocene sediments that are composed of

thick turbidite and pelagic sequences (DeGenevraye and Samuel, 1972; Smyth et al, 2003 &

2005). The turbidites are recorded in the Mioceneage Kerek Formation.

The objectives of this article are to unravel thedepositional model, then subsequently constructan understanding of relation between turbidite andreservoir sand bodies based on geometry and

distribution pattern of the Kerek Formation. Thisarticle emphasizes on outcrop-based study in

order to get a comprehensive understanding aboutdeepwater play characteristics in an active marginsetting.

Figure 1. Digital elevationmodel (Shuttle Radar

Transect Mission) overlain byschematic zonation of East

Java. The study area isbounded by black square(modified from Smyth et al,2003 .
mailto:[email protected]:[email protected]:[email protected]:[email protected]


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METHODS

The study includes outcrop visits to produce

sedimentological logs (Figures 3 and 4), geologicalmap and acquire rock samples for laboratoryanalyses. The laboratory analyses are comprised of

petrographical and paleontological analyses.Outcrop data and lab results were then used in

geological modeling. The turbidite sandbodiesmodel (Figures 5 and 6) was built by correlatingthe sedimentological sections (chronostratigraphiccorrelation), then gridding and layering vertical

horizon of sandbodies without involving fault

model. All of these steps were done by usingstandard 3-D geological modeling softwarepackage.

FACIES & ARCHITECTURAL MODEL

Interpretation of sedimentological logs taken fromthe outcrops revealed that their depositional facies

are of fan complex, particularly of lower fansystem. The lower fan system was formed byaccumulation of individual lobe fans and pelagicdeposits, which are products of high and low

density turbidity current.

Figure 2. Simplified geological map of the study area shows four lithostratigraphic units. The

calcareous sandstone of Kerek Formation is shown in yellow colour.

Figure 3. Outcrop of Kerek Formation with representative KJ 98 sedimentological log along the Tuntang

River, Kedung Jati Village.


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Figure 4.Sedimentologicallog of KJ-85 that

is composed sheetsandstone of fanlobe in the lower

section andgradually changeto massivesandstone in the

upper section.


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Figure 5. Correlation section of the sedimentological logs. The section is f lattened on N16 marker.


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The characteristic lithofacies comprised in eachdepositional facies of the lower fan system and itsgeometry are described below:

a.Pebbly massive sandstone of submarinemiddle fan

The massive sandstone of lower fan deposit

typically consists of some lithofacies that combinetogether. Massive coarse sandstone with erosionalbase contact dominates the lower portion of thedeposit. Gradually normal graded sandstone and

stratified pebbly sandstone occur on several placesas a remark of temporary hydraulic change of thecurrent. Stratified medium-grained sandstone capthe upper part of the deposit. The entire package

shows a fining upward stacking pattern. Suchcombination of features is interpreted as the resultof high density turbidity current that occurs on afan. The process began with initial high densityand velocity of the current allowed for the

transportation and deposition of coarse-grainedmaterials. As the current kept distributing thematerials to another part of the system, finally onthe upper part of the deposit, finer-grained

(stratified medium-grained sandstone) are moredominant. The results of 2D correlation and 3Dmodeling show that the mean thickness and sandbody distribution are 0.6 m and 4585.6 m,

respectively. The minimum thickness anddistribution of sand bodies are 0.25 m and 1403m, respectively. The length of the fan as inferred

from a single representative lobe is 1580 m (Figure8).

b.Sandstone sheets of submarine lower fanThis deposit consists of several lithofacies that canbe easily classified by using Bouma sequenceclassification (Ta-Te) [Bouma, 1962]. Intercalationof graded sandstone with erosional contact (Ta),

convolute sandstone (Tc), parallel laminatedsiltstone (Td), and stratified mudstone (Te) occurmonotonously all over the deposit. Thin bed ofconvoluted lamination sandstone also occurs

simultaneously with another lithofacies, which

provides evidence for low density turbidity current.This is due to the current become less dense and

the velocity of the current become less unable todistract semiplastic sediments (Bouma, 2000). It

has been widely accepted that convolutedlamination is the result of distraction of current onsemiplastic sediments, therefore low densityturbidity current produce thin or even no

convolute structure (Shanmugam, 2005). Theresult of 2D correlation analysis shows that themean thickness and distribution of sand bodiesare 0.08 m and 2855.4 m, respectively, with the

minimum thickness and deployment of sand

bodies being 0.02 m and 1011 m, respectively. Thelength of the fan, as inferred from a single

representative middle fan is 1264 m.

c.Pelagic mudThis deposit consists solely of thick mudstone

lithofacies. Pelagic mud is the result of suspensionprocess that occurs in almost all deep sea setting.

PALEOCURRENT ANALYSIS

Paleocurrent direction can be identified from avariety of erosional structures such as tool mark,grove cast and flutecast. In the study area,paleocurrent direction was analysed from flute cast

structures. The flute cast structure measurementsindicate that the main trend of sediment supplymoving from north to south with average directionof N 144o E (NW-SE) (Figure 6).

DISCUSSIONS AND CONCLUSIONS

The unique characteristic possessed by turbidite

sediments in the Western Kendeng Zone is that

they are part of fan lobe complex and encompassesmixed sand and mud with overall coarsening

upward stacking pattern. Tectonically, turbiditedeposits within the Kendeng Zone and its vicinityare quite different due to the active margin andvolcanic arc setting. Kendeng zone as the main

depocenter received a lot of sediment contributionfrom Southern Mountain Zone to the south and

Rembang zone to the north.

Therefore these turbidite sequences predominantlycomposed mixed of siliciclastic, volcaniclastic and

even carbonate content (Smyth et al, 2005;

Subroto et al, 2007). Paleocurrent analysis showsthat sand supply came from the NW towards SE,

most likely from Rembang High and was depositedinto Kendeng low. The 3D modeling could depictthe architectural element of deep water fancomplex, focusing on sandy facies formation that

Figure 6. Paleocurrent analysis as measuredfrom grove (top) and flute cast (bottom) structures

yielded NW-SE depositional trend.


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has a significant implication to reservoir geometry(Figure 7). Middle fan sandstones are rarely foundin the study area, as only 10 out of 130 sandbodies were identified as middle fan deposit whose

thin section results showed that they are wackysandstones. The thickness slice of 3D modelingyields the mean thickness-width ratio of massivesand bodies 1:1300 m, with porosity of around0.03 to 0.15. Therefore, it is mostly considered to

be a precisely analog of turbidite reservoir in theWestern Kendeng. There are 120 existing sandbodies in the study area which are interpreted aspart of the lower fan lobe. They are composed of a

thin sheet sands interbedded pelagic mud withmean thickness-width ratio analyses fromhorizontal slice of 3D sandbodies modeling 1 : >2000 m. However, lower fan sands have not been

considered eligible to be reservoir analog due topoor rock property values (porosity ranges from0.01 to 0.05), quite thin sand and rich in clay

mineral (Figure 8).

Deep water processes in western Kendeng Zonehas produced a variety of stacking turbidite sands.Two-dimensional correlation reveals fan lobesswitching in this area. They have compensational

stacking character which fans are verticallymigrated due to high accommodation space withbalanced sedimentation rate (Mutti and Davoli,1992). Meanwhile the sheet sands are significantlyretrogradely-stacked in lower Kerek Formation,

which are continuously-distributed to overall area,and they represent lower fan lobe sands, althoughin some place only a half part of the lobes isdiscovered. It probably proves the lobe geometry is

greater than expected during study. Beside in theupper part of the Kerek Formation, the sand lobestend to be thinner and smaller. This study mightbe useful to provide turbidite reservoir analogue

model for subsurface application and for futurehydrocarbon exploration in the western KendengZone.

A B

C Index MapKJ-13

KJ-92

KJ-98

KJ-100

KJ-85

Paleocurrent

Figure 7. A)3D model showing the succession of deepwater fan facies sandbodies. B) Thickness-orientedslice within sandstone sheets of lower fan lobe and C) Thickness-oriented slice of pebbly massive.


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ACKNOWLEDGMENT

This study is part of the authors thesis, which wassupported by Department of GeologyUPNVeteranYogyakarta, PT Seleraya Energy and

GeoPangea Research Group. Specialacknowledgment is made for Riswa Galena and

MM team as partners on the fieldwork, LeonTaufani and Agung Budiman for good discussion,

UPN geology laboratories for samples analysis andFOSI to publish this article.REFERENCES

Bouma, A. H., 1962, Sedimentology of SomeFlysch Deposite, A graphic approach to fasiesinterpretations: Elsevier Co., Amsterdams,

Netherlands.Bouma, A. H., 2000, Coarse-grained and fine-

grained turbidite systems as end membermodels: applicability and dangers: Marine andpetroleum Geology , Elsevier.

De Genevraye, P., and Samuel, L., 1972, Geologyof the Kendeng Zone (Central & East Java):

Proceeding Indonesia Petroleum Association,First Annual Convention, Jakarta, Indonesia.

Mutti, E., and Davoli, G., 1992. Turbiditesandstones: AGIP, Istituto di geologia,Universit di Parma.

Shanmugam, G., 2005, Deep-Water Processes and

Facies Models: Implications for sandstonepetroleum reservoirs: Handbook Of PetroleumExploration And Production 5, Department of

Earth and Environmental Sciences TheUniversity of Texas at Arlington Arlington,

Texas, U.S.A.Smyth, H., Hall, R., Hamilton, J.P., and Kinny, P.,

2003, Volcanic origin of quartz-rich sediments

in East Java: Proceedings Indonesian PetroleumAssociation 29th Annual Convention &Exhibition, Jakarta.

Smyth, H., Hall, R., Hamilton, J., and Kinny, P.,

2005, East Java: Cenozoic Basins, volcanoesand ancient basement: Proceedings IndonesianPetroleum Association 30th Annual Convention,Jakarta.

Subroto, E.A., Noeradi, D., Priyono, A., Wahono,H.E., Hermanto, E., Praptisih and Santoso, K.,2007, The Paleogene Basin within the KendengZone, Central Java Island, and implications tohydrocarbon prospectivity: Proceedings

Indonesian Petroleum Association 31st AnnualConvention & Exhibition, Jakarta.

1

2

3

4

56

7

8

9

10

Mean

Median

Modus

Max

Min

1.2 7310

0.25 1403

-

4585.6

4630

-

3012

7265

0.607

0.515

Massive Sandstone Fasies Geometry

0.5

Based on 2D CorelationBased on 3D Fance

Diagram

0.35

Sandstone Layer

Length (m)

0.46

1580

14030.53

0.25

1

Datum N16

1.20.65

73103950

Distribution of sands

bodies (m)Thicknes (m)

28450.68

5800

5310

5316

3645

0.45

0

10

20

30

40

50

60

70

KJ 9 KJ 13 KJ 98 KJ 100

Calcareous Sandstone

Calcareous Mudstone

Measuring Section

%

(%) Lithology :

A B

C

Figure 8. A) 3D sandbody modeling. B) Example statistics of massive sandstone facies sandbodies. C)Sand-shale percentage from several sedimentological logs.


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A Case Study on Using Mundu-Paciran Nannofossil Zones(MPNZ) to subdivide Mundu and Paciran Sequences in theMDA Field, East Java Basin, Indonesia

Azhali Edwin, Kian Han and Wildanto Nusantara

Husky CNOOC Madura Limited

Corresponding Author: [email protected], [email protected] and [email protected]

ABSTRACT

The Husky-CNOOC Madura Limited (HCML) MDA-4 exploration well (2011) in the Madura Strait

region targeted Globigerina limestones in the Mundu Sequence (3.8 Ma) and the Paciran Sequence(2.0 Ma). The MDA Field is covered by Merpati 3D Seismic (2005). Seismic features observed fromthe 3D volume include phase change or polarity reversal at the top of gas filled reservoirs of theMDA structure and DHI flat-spot approximating to the gas-water contact (GWC). The reservoirs are

primarily planktonic foraminifera grainstones, packstones and wackestones that have been

deposited as pelagic rains and were subsequently redistributed by sea floor bottom currents.

Differentiating the Mundu and Paciran Sequences relies heavily on biostratigraphy and

chronostratigraphy, as there are no significant lithological features that can be observed betweenthe sequences. This article introduces a method to construct detailed well correlations of the twosequences based on MunduPaciran Nannofossil Zones (MPNZ), using high resolutionbiostratigraphy events. The methodology uses varying nannofossil abundances in the interval NN18(Late Pliocene) to NN11 (Late Miocene). The best reservoir performance in the study area may occur

in the MPNZ-7 and MPNZ-6, which were deposited at the late stage of the depositional cycles.

INTRODUCTION

The Madura Strait Block (Madura Strait PSC) hasa long history of exploration with the first well

drilled back in 1970 (MS-1-1, dry hole, CitiesService Inc.). The last exploration well drilled

before the block was acquired by HuskyCNOOCMadura Limited in 2008 was the MDA-3 well(1992, dry hole, MOBIL Madura Strait Inc.). TheMDA-3 was an appraisal well delineating a

reservoir boundary at the north of the MDAStructure.

Following a period of 19 years without explorationactivity within the block, the MDA-4 explorationprogram was proposed and initiated during 2011(Figure 1). The MDA-4 targeted the Globigerina

limestones of the Mundu and Paciran Sequences.This well was a discovery, confirming a gas fieldand provided support for considering potentialdevelopment options. Work continued with ProjectEngineering & Design (PED) preparation and

approval. The final Plan of Development (POD) wasapproved by GOI in January 2013; two years afterthe well was drilled. This is possibly the fastestcycle of discovery to POD approval in the region.

Figure 1. Madura Strait PSC Block.
mailto:[email protected]:[email protected]:[email protected]:[email protected]


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The Mundu Sequence (3.8 Ma) and PaciranSequence (2.0 Ma) (in East Java-Maduralithostratigraphy terminology they were known asMundu and Selorejo Formations, respectively),

consist primarily of planktonic foraminiferagrainstones, packstones and wackstones. They areconsidered to have been deposited as pelagic rainsand were subsequently redistributed by sea floorbottom currents. Differentiating the Mundu and

Paciran Sequences relies heavily onbiostratigraphy and chronostratigraphy as nosignificant lithological features can be observedfrom samples and logs between those two

sequences. Detailed well correlation of MDA wellswas generated based on MunduPaciranNannofossil Zones (MPNZ), using high resolutionbiostratigraphy events. The methodology uses

varying nannofossil abundances in the intervalNN18 (Late Pliocene) to NN11 (Late Miocene).

REGIONAL GEOLOGY

The Madura Strait Block is located in the southernpart of East Java Basin; a back-arc basin boundedto the west by Karimunjawa Arch and to the south

by Java Volcanic Arc (Satyana et al., 2004; Figure2). The basin deepens eastwards into the LombokBasin while to the north of the basin shallows tobecome the Paternoster High (Satyana and

Djumlati, 2003). The block is located in an offshorearea between Madura Island to the north and thepresent-day East Sunda volcanic arc to the south.

The offshore area of East Java demonstrates an

excellent example of Miocene Recent structuralinversion of a Paleogeneextensional/transtensional basin system. Thecontinued inversion and differential compaction

during Plio Pleistocene time is a further primarycontrol on sedimentation. Seismic data show acomplex structurally controlled sequence

stratigraphy (Bransden and Matthews, 1992).

There are several reservoir objectives in the area,ranging from Eocene to Pliocene in age. The HCML

MDA-4 well is one of many proposed explorationwells, targeting the Late Miocene Late Pliocenereservoir (Figure 3). This foraminifera-dominatedreservoir was encountered in many exploration

wells in the East Java Basin and also developed inseveral onshore East Java areas.

Schiller et al (1994) suggested that there are atleast two distinct types of Globigerina

sand/limestone deposits in the East Java Basin,i.e.: planktonic foraminifera sands driftsdeposited by bottom currents, which he consideredas the dominant process; and less pervasive

planktonic foraminifera turbidites deposited as

submarine channel-fills and fans. The Globigerinalimestone (GL limestone) in the MDA-4 well wasinterpreted as the result of pelagic rain deposition

and subsequently redistributed by sea floor bottomcurrents. This process is similar to the planktonicforaminifera sand drifts deposited by bottom

currents that was proposed by Schiller et al(1994).

MDA FIELD

The MDA Field was discovered in 1984 by theHudbay MDA-1 exploration well, drilled on a crestat the eastern part of the structure. This well wasdrilled to 4,016 feet subsea and tested 28

MMSCFD of gas. The discovery was confirmed bythe MDA-2 exploration well, which was locatedabout 250 m southwest of the MDA-1. The MDA-3

appraisal well was drilled at the northern edge ofthe structure; approximately 2 km northwest ofthe MDA-1 and MDA-2. The objective of the MDA-3was to confirm a possible gas water contact at the

northern edge of the field. The well was considereda dry hole due to poor reservoir quality.

The MDA-4 appraisal well was drilled in 2011 and

it successfully confirmed MDA Fields gas reserve.The well tested gas flow rates of 18.7 MMSCFDfrom Pliocene reservoir (Paciran Sequence) and 8.3MMSCFD from Pleistocene turbidite reservoir of

the Lidah Sequence.

SEISMIC CHARACTERISTICS

The MDA Field is covered by 80 sq.km of marine3D seismic, which was acquired as part of a muchlarger Merpati 3D survey in 2005. In 2009, the

data was reprocessed through Pre-Stack TimeMigration (PSTM) and Pre-Stack Depth Migration

(PSDM).

All seismic sections in this article are displayed onzero phase data and following SEG convention, in

which positive reflection coefficient is displayed aspeak and negative coefficient as trough.

Two Direct Hydrocarbon Indicator (DHI) featuresobserved on the MDA structure, a polarity reversalat the top gas-filled reservoirs and a seismic flat-spot indicating the gas-water contact. These

features helped reduce geological risk and increase

confidence to drill.

RESERVOIR LITHOLOGY ANDNANNOFOSSIL BIOSTRATIGRAPHY

The reservoir rocks in the MDA Field consist of theMundu and Paciran Sequences (Figure 3). The

sequences and chronostratigraphic labels followthe convention and descriptions of Goodall (2007).The Mundu Sequence is bounded by the T40 andT50 sequence boundaries (7.3 and 3.8 Ma,

respectively). The Paciran Sequence is bounded bythe T50 and T60 sequence boundaries (3.8 and 2.0

Ma, respectively). Within both sequences, there areseries of bioclastic grainstones, packstones and

wackestones. These reservoirs are in ageequivalent and have the same lithologies asSANTOS Maleo Field (Triyana et al, 2007).


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Figure2.E

astJavaBasin

geologicalsetting

(Satyana

etal.,

2004).

Oil

field

Ga

sfield


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The foraminifera association of both sequences

indicates that the water depth is approximating tothe range 100-500 m, where planktonic

foraminifera were deposited as pelagic rain andthen were subsequently redistributed by sea floor

bottom currents. This process resulted in thegrainstone, packstone, wackestone observed in the

wells to show distinct, rhythmic coarsening-upward cycles. A similar depositional process tookplace in SANTOS Oyong and Maleo Fields (Iriska

et al., 2010), which are located 150 km and 70 km,respectively, to the west of the HCML MDA Field.

Differentiating these Mundu and Paciran

Sequences relies heavily on biostratigraphy andchronostratigraphy, as there are no significantlithological features that can be observed fromsamples and logs of those two sequences. The

methodology used was initially invented and

developed by Goodall (2007), with varyingnannofossil abundance relative to sequenceboundaries in the interval NN18 (Late Pliocene) toNN11 (Late Miocene) helping to define a rigid

stratigraphical framework.

The detailed correlations in the MDA Field were

constructed using high resolution biostratigraphyevents of the Late Miocene- Pleistocene MPNZ

(MunduPaciran Nannofossil Zones). This methodis generated based on cutting data from four wells

and also conventional cores of MDA-3 and MDA-4.The subdivisions are as follows (the youngest zone

is mentioned first):

MPNZ-8: Pleistocene age bounded by T60 and T65.

MPNZ-7: The first downhole occurrence ofDiscoaster brouweri with less abundantSphenolithus abiesand any other nannofossil. This

zone has reworked materials from olderstratigraphy.

MPNZ-6: The first downhole occurrence of

common-abundant small Reticulofenestridsand in-

situ Sphenolithus abies is used to date this event.The absence or significantly decreased (downhole)occurrence of Gephyocapsa is also noted in this

subzone.

Figure 3. East Java Basin chronostratigraphy.


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MPNZ-5: This event is recognized by the firstdownhole occurrence of (super) abundant smallReticulofenestrids.

MPNZ-4: Defined by the first downhole occurrenceof few-common Sphenolithus abiesand/or mediumReticulofenestrids. The first downhole occurrenceof few-common Dictyococcites spp also

characterizes the event.

MPNZ-3: This event is marked by the first

downhole occurrence of abundant Sphenolithusabies.

MPNZ-2: This event is characterized by the

maximum abundance ofReticulofenestrids and/orSphenolithus abiesduring the Early Pliocene.

MPNZ-1: This event is coincident with the firstdownhole occurrence of in situ Discoaster

quinqueramus(also used to mark the Late Miocene

- Pliocene boundary) and the first downholeoccurrence ofReticulofenestra rotaria. A downholesignificant increase of medium Reticulofenestrids

and the absence of in-situ Dictyococcites spp. arealso noted at this subzone.

CONCLUDING REMARKS

Inversion in Madura Strait region that took placein the Late Miocene created humps on the sea

floor. The forams were deposited as pelagic rainand were re-distributed in the area by strongcurrents coming from the Indian Ocean through

the Bali Strait. These currents created a clinoformstructure around the seabed located at relativelyhigher position from its surrounding. The evidence

of this clinoform can be seen at MPNZ-6

relationship between MDA-1 and MDA-2st wells(Figure 5).

Based on the MPNZ subdivision, the top of MPNZ-7

in the MDA Field occurs within the SelorejoFormation (Figure 6). The Selorejo Formation isbased on lithostratigraphy, which means theformation top does not necessarily coincide withtime event. The upper reservoir interval of the MDA

Field is younger than the MPNZ-7 and it lies withinthe lower part of MPNZ-8 (Lidah Sequence, LatePliocene - Early Pleistocene). This interval wasinterpreted as part of reworked materials from

older deposits.

The MPNZ-7 was only encountered in the MDA-3(northern edge of the structure) and MDA-4

(western portion of the structure), which isbelieved to be composed of reworked sedimentsfrom the eastern portion of the structure. This

interpretation is supported by the fact that MPNZ-

7 deposit was not encountered in MDA-1 andMDA-2ST (Figures 4, 5 and 6).

Based on internal reservoir characteristics, the

MPNZ-7 deposit in MDA-3 has less porosity andpermeability compared to similar reservoir in theMDA-4; and this corresponds to the increase ofmud content in the MDA-3. Hence, the facies

changes relative to the west of the structure duringMPNZ-7 time. It is interpreted that the MDA-3reservoir was deposited by less winnowingcompared to the reservoir in the MDA-4, due to the

relatively low position in the structure.

Based on the above interpretation, it is suggestedthat the best reservoirs are the MPNZ-7 andMPNZ-6, which were deposited at relatively high

position in the depositional setting.

Figure 4. Seismic amplitude cross section showing top MPNZ 7 and MPNZ 6 with facies change betweenMDA-4 and MDA-3 (MPNZ 7 age) and MDA-1 and MDA-4 (MPNZ 6 age).


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ACKNOWLEDGEMENTS

We would like to thank Budiyento Thomas and

Joint Venture of HuskyCNOOC Madura Limitedfor permission to publish this article; JefferyGoodall, Arnie Ferster and Fernando Gaggino for

reviewing this article. Discussions and comments

from them have significantly improved this article.

REFERENCES

Bransden, P. J. E., and Matthews, S. J., 1992,Structural and Stratigraphic Evolution of The

East Java Sea, Indonesia: ProceedingsIndonesian Petroleum Association 1992.

Goodall, J. G. S., 2007, Madura Basin

Stratigraphic Study, Joint BPMigas/Santosinternal study.

Iriska, D. M., Sharp, N. C., and Kueh, S., 2010,

The Mundu Formation: Early ProductionPerformance of An Unconventional LimestoneReservoir, East Java Basin Indonesia:Proceedings Indonesian Petroleum Association

2010.Satyana, A. H., and Djumlati, M., 2003, Oligo-

Miocene Carbonates of the East Java Basin,

Figure 5. AI cross section showing top MPNZ 7 and MPNZ 6 with facies change between MDA-4 and MDA-3(MPNZ 7 age) and MDA-1 and MDA-4 (MPNZ 6 age).

Figure 6. Well correlation between MDA wells.


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Indonesia: Facies Definition Leading to RecentSignificant Discoveries: AAPG InternationalConference 2003.

Satyana, A.H., Erwanto, E., and Prasetyadi, C.,

2004, Rembang-Madura-Kangean-Sakala(RMKS) Fault Zone, East Java Basin: The Originand Nature of a Geologic Border, IndonesianAssociation of Geologists 33rd AnnualConvention, Bandung 2004.

Schiller, D. M., Seubert, B. W., Musliki, S., andAbdullah, M., 1994, The Reservoir Potential ofGlobigerina Sands in Indonesia: ProceedingsIndonesian Petroleum Association 1994.

Triyana, Y., Harris, G. I., Basden, W. A., Tadiar, E.,and Sharp, N. C., 2007, The Maleo Field: AnExample of The Pliocene Globigerina BioclasticLimestone Play In The East Java Basin Indonesia: Proceedings Indonesian Petroleum

Association 2007.


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Short Note : Mineral Composition of Eocene and MioceneSandstones in Java Island

Herman Darman1, Budi Muljana2 and J. T. van Gorsel3

1Shell International EP Netherlands2Geology Department, University of Padjadjaran Indonesia3Geoscience Research / Consultant

Corresponding Author: [email protected]

INTRODUCTION

A number of studies discuss the mineralcompositions of Cenozoic sandstones in Java

Island, Some sandstones are dominated by quartz,derived from granitic and/or metamorphic

basement terrains or reworked sediments; manyothers are dominated by lithics and plagioclasefeldspars derived from andesitic volcanics. The

distribution of these two end-members varies

through space and time, and has not beensystematically been document for all of Java.

In the first comprehensive study of the geology ofJava, Verbeek and Fennema (1896) suggested thatmost of the Neogene sandstones on Java wereerosional products of volcanic rocks, and that

quartz-rich sandstones were either of Eocene ageor were deposited in the proximity of Eocene rocks.

Rutten (1925), however, studied 110 Neogenesandstones across Java and demonstrated that

many of the Miocene sandstones are also rich in

quartz, particularly across the northern half JavaIsland and on Madura Island (Figure 1). Thesehave common 'dusty quartz' and quartz with

undulose extinction patterns (both indicative ofmetamorphic quartz), and were interpreted asclastic material derived from 'old rocks of Sunda-

land'. He also observed that grain sizes of Neogenesands generally decrease in Southern directionand that andesitic material is not common beforethe Late Neogene (probably meaning Late Miocene

and younger).

More recent work in West Java by Clements andHall (2007) and Clements et al. (2012) largelyconfirmed the patterns established by Rutten

(1925):

(1) Sandstones of Eocene and Oligocene age acrossall of West Java are virtually all quartz-rich, and

can be tied to 'Sundaland' Pre-Tertiary graniteand-metamorphic basement sources North of Java;

(2) Increase in volcanic detritus in Early Miocene

and younger sandstones, particularly in SouthJava and the axial basins, where all sandstones of

this age are typically sourced from the LateOligoceneEarly Miocene "Old Andesites" volcanicarc of the Southern mountains and the Late

Miocene- Recent modern arc across the axial zoneof Java.

Smyth et al. (2008) provided additional detail on

sandstone composition from East and CentralJava. They essentially confirm the same patternsas in West Java, but found that some of the Lower-Middle Miocene sediments in the SouthernMountains are quartz-rich, but are composed of

volcanic quartz (monocrystalline, clear, oftenbipyramidal) and are sourced from local acidvolcanic rocks.

The purpose of this short note is to contribute tothe subject of Java sandstone provenance bysummarizing quantitative analyses on sandstonecompositions in the recent studies by Muljana &

Watanabe (2012), Darman (1991), Siemers et al(1992) and Smyth et al (2008) and provide someadditional data points as QFL (Quartz- Feldspar-

Lithics) ternary plots.SANDSTONE GROUPS BASED ON MINERALCOMPOSITIONS

There are two groups of sandstones based on their

composition: a) Non-quartz dominated sandstonesand b) Quartz dominated sandstones.

Non-quartz dominated sandstones are found inWest and Central Java (G & F, Figure 1). Muljana

& Watanabe (2012) studied the Miocene Cinamboand Halang formation in Majalengka area, WestJava. The quartz composition decreases from thelower to middle Miocene followed by increasing ofrock fragment (Figures 2A and 2B). The rock

fragment composition was dominated by andesitefragments. These sandstones were deposited whenthe magmatic and tectonic influences areparticularly dominant. The upper Miocene Halang

Formation is distinguished by the volcanic content.

Darman (1991, Figure 2C) studied the upper

Miocene Halang Formation in the north of CentralJava and here the sandstones have a lower quartzcontent. The majority of the rock fragments arevolcanics and are rich in plagioclase minerals.

Similar to the Majalengka area, the HalangFormation is a turbidite deposit.

Based on the Dickinson classification diagram

(1985, Figure 2D) some of the Lower Miocenesandstone were derived from a recycled orogenyterrain. The upper Miocene Halang Formationsandstones in both Majalengka and Brebes camefrom a range of sources such as dissected to

undissected arc in the south to southeast of the
mailto:[email protected]:[email protected]


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Figure1.ModifiedphysiographymapofJa

vaaftervanBemmelen(1949),whichincludelocationsofsan

dstonesampleswithpointcountinganalysisand

the.distributionofquartz-rich("old";mainly

inNorth)versusvolcanics-rich

("effusive";SouthernMountains

andBogor-KendengTroughs)

sandstonesacross

Java(Rutten,1925).


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area.The sandstones compositions of the Bayah

Formation (A, Figure 1) and the Walat Formation(B, Figure 1) of SW Java are dominated by quartz

(Figure 3). These formations were deposited duringEocene time (Siemers et al, 1992). The outcropanalysis indicated a mix of fluvial and shallowmarine sandstones. In Central and East Java,

Smyth et al (2008) also found a number of quartz-rich sandstones. The provenance of thesesandstones are interpreted as recycled orogen

terrain in the north to northeast of the outcrops.

In the southern part of Central Java, Smyth et al(2008) found metamorphic quartz rich sandstone

(Figure 4A), deposited in a terrestrial environment

during pre-Middle Eocene time, classified as Type1, in 3 locations (C in Figure 1). These are pre-

middle Eocene sandstones and described asmetamorphic quartz-rich sedimentary rocks,

deposited in terrestrial environment

In the Southern mountains Miocene volcanicquartz-rich sandstones were found in outcrops.

Smyth et al (2008) classified these sandstones asType 2 (Figure 4B), which are located in closeproximity to the acid volcanic centers of the

Eocene to Lower Miocene Southern mountain arc

(Location D, Figure 1). The presence of lignite,channel structures and abundant rootlets, and thelack of marine fauna indicate a terrestrial

depositional setting (Smyth et al, 2008).

Figure 2. Quartz, Feldspar and Lithics ternary plot of sandstones from the Halang Formation. A and B are

from Majalengka, West Java and C is from Central Java. D is the provenance categories of sandstone basedon Dickinson (1985).


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JAVABerita Sedimentologi

Number 26 May 2013

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