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PROCEEDING, SEMINAR NASIONAL KEBUMIAN KE-8
Academia-Industry Linkage
15-16 OKTOBER 2015; GRHA SABHA PRAMANA
UNLOCKING HETEROGENETIC RESERVOIR BY USING SEQUENCE STRATIGRAPHY ON
SANDY FLUVIAL DEPOSITS OF THE MIDDLE BALIKPAPAN FORMATION OUTCROP,
SAMARINDA, KUTEI BASIN; IT’S IMPLICATION FOR RESERVOIR DISTRIBUTION
Rizki Putra Ptratama1
Diponegoro Ariwibowo2
Zakaria Yahya3
Geologiical Student of STT Migas Balikpapan, prezky@rocketmail.com
Geological Student of STT Migas Balikpapan, dhiponaw@gmail.com
Geolgical Student f STT Migas Balikpapan, zakariayahya333@gmail.com
ABSTRACT
Basically, Sequence stratigraphic concept has used for analyses of seismic cross- sections, well logs and
outcrop studies of sedimentary rock are used to predict the thickness, extent of sediment lithology and
understanding sediment geometry changes with relative sea level and rates of sedimentation. The
sequence principles can be applied readily to outcrop sources. This paper will fully discuss the sequence
stratigraphic concept of heterogenetic facies on Gelingseh formation (Balikpapan Group). The data were
collected from the surface outcrops in Simpang pasir area, Samarinda through field geology mapping.
Then we continued to a laboratory analysis of said Miocene outcrops within study area. Several individual
facies, in terms of deposition events, were determined in the study area. There are 8 facies associations
from four stratigraphic logs: 1) Pebbly – Very Coarse Grain Sandstone (Gradding Oriented), 2) Fine
Grain Size – Medium Grain Size Massive Sandstone, 3) Massive Mudstone (Shale Clast), 4) Massive
Mudstone (Silt Clast), 5) Fine Grain – Coarse Grain through cross bedding Sandstone, 6) Fine Grain
– Medium Grain Mud Drapes Associate Cross Lamination Sandstone, 7) Fine Grain – Medium Grain
Laminae Sandstone, 8) Coal Seam. According to the integration of all the individual beds, an analysis of
the vertical stratum succession, with nearly complete sequences, are observed at the outcrops in the study
area. This study has interpreted comprehensive sand deposits in a fluvial deltaic, which will be useful to
encourage future exploration and development.
Keywords: Heterogenetic Reservoir, Sequence Stratigraphy, Fluvial Deposits,
Middle Balikpapan Formation, Kutei Basin
I. INTRODUCTION This study be located at simpang pasir area,
Samarinda, East Kalimantan. This area
Basically, Sequence stratigraphic concept includes the northen part of kutai basin (figure
has used for analyses of seismic cross-sections, 1).
well logs and outcrop studies of sedimentary
rock are used to predict the thickness, extent of The Kutai Basin formed in the middle
sediment lithology and understanding sediment Eocene as a result of extension linked to the
geometry changes with relative sea level and opening of the Makassar Straits and Philippine
rates of sedimentation. The sequence principles Sea (I.R Cloke,et all,1998). Kutai basin is the
can be applied readily to outcrop sources. second largest Tertiary basin that produced oil
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PROCEEDING, SEMINAR NASIONAL KEBUMIAN KE-8
Academia-Industry Linkage
15-16 OKTOBER 2015; GRHA SABHA PRAMANA
and gas in Indonesia, with proven reserve subsidence and sag were followed by inversion
more than 11 BBOE (Corutney, et al., 1997). of the early Kutai Basin fill along its initial
More than 85% reserve is located in the Middle boundary faults in the early Miocene, resulting
Miocene sediment. Subsequent tectonic events in the erosion of several thousand meters of the
uplifted parts of the basin margin by the late synrift sequence.
Oligocene. This uplift was associated with the The structural pattern of South Kutai
deposition of the Sembulu Volcanics in the Basin is characterized by the presence of NW-
eastern part of the basin. SE fault trends that are almost perpendicular to
The second stratigraphic phase was the central Kutei Basin structural trend
contemporaneous with basin uplift and .Three major faults (from SW to NE and from
inversion, which started in Early Miocene time. the oldest to the youngest) are Maruat, Tunan,
During that time, a vast series of alluvial and Sesumpu - Jumelai and Sepinggan Faults
deltaic deposits were deposited in the basin. (Syarifuddin et al., 2008).
They comprise deltaic sediments of the III. SAMPLE AND METHOD
Pamaluan, Pulau balang, Balikpapan and
Kampung Baru Formations, prograding This paper will fully discuss the sequence
eastwards, which range in age from the Early stratigraphic concept of heterogenetic facies on
Miocene to Pleistocene times . Deltaic the Middle Balikpapan formation. The data
deposition continues to the present day, and were collected from the surface outcrops in
extends eastwards into onshore Kutei Basin Simpang pasir area, Samarinda through field
(figure 2). geology mapping. Then we continued to a
II. REGIONAL GEOLOGY laboratory analysis of said Miocene outcrops
within study area.
The Kutai Basin is bounded by the The outcrop data will be used as an analog
Paternoster platform, Barito Basin, and the to the subsurface data to understand the lateral
Meratus Mountains to the south, by Schwaner stratigraphy distribution and reservoir
Block to the southwest, the Mangkalihat high to characterization. The startigraphy succession
the north - northeast, and the Central Kalimantan and stacking pattern in the subsurface has the
Mountains to the west and north (figure 3). similarity to the outcrop sediments at the same
Kutei Basin has a complex history (Moss et al., age in the Mahakam Delta. And a surface
1997), and is one of the only Indonesian basins geological map of Samarinda Area by S.
to have evolved from a rifted internal Supriatna, Sukardi dan E Rustandi was used to
fracture/foreland basin into a marginal-sag. identify formation outcrop location (figure 4)
Much of the early basin fill in the Kutei
Basin has been inverted and exposed (Satyana, IV. DATA AND ANALYSIS
1999).
The basement uplift of Kuching High and Outcrop Data
inversion from upper Kutai Basin contributes Lithofacies analysis
erosional debris from previous sediment, A number of different depositional
accumulating thick. progradational deltaic environments exist in any sedimentary basin.
system to east and south direction. Oligocene These environments represent local variation in
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PROCEEDING, SEMINAR NASIONAL KEBUMIAN KE-8
Academia-Industry Linkage
15-16 OKTOBER 2015; GRHA SABHA PRAMANA
physical, chemical and biological conditions as interbedded mud drapes in laminae medium
well as distance and direction from depositional grain sandstone which is associated with a thick
agents entering basin (e.g. a river and its coal seam and shown by a dark color, Blocky
delta). At any moment sediments being and planar bed contacts, a coarsening upwards
deposited may be correlated with local sandstone unit. This sub-facies are found in
depositional environments. These lateral observation point number 8 in the East research
variations are termed sedimentary facies. area
Lithofacies is a body of rock characterized by Interpretation : Numerous grain classes in
particular combination of lithology, physical and the first association facies represent high-
biological structure that bestow an aspect energy deposition with traction of the
different from the body of rock above, below bedload (Scholle and Spearing, 1998).
and laterally adjacent. The association facies indicates a braided
Based on the outcrop studies, there are 8 fluvial stream (Scholle and Spearing,
lithofacies that represent particular characteristic 1998). Further indications are the clast size,
Facies association analysis Constitute several erosional contacts, the graded bedding
facies that occur in combination, and typically (inverse and normal). Both sandy and gravelly
represent one depositional environment (tabel rocks migrated laterally, leaving sheet-like
1). The outcrops of the research area are or wedge-shaped deposits of channel and bars
observed in four stratigraphy profile (Figure 5 complexes, preserving a minor amount of
and 6). floodplain materials (Scholle and Spearing,
Outcrop I : 1998). The depositional environment of this
association facies is likely a channel in a
Description : We found this facies to have braided river.
several external characteristics. sub-facies of Outcrop II :
massive coarse grain sandstone associated
monotoneous interbed of massive siltstone and Description : We found a sub-facies of
laminae of fine grain sandstone which had Crossbed, lamination, medium grain
brownish grey color, sharp and planar bed sandstone, associated with alternate massive
contacts, coarsening upwards sandstone unit mudstone and represented by a brownish light
averaging 4.95 m in thickness, and ranging up to color, sharp and planar bed contacts, and a
9,45 m It has rounded sub- rounded grains with, coarsening upwards sandstone unit. It has
medium sorting. These sub-facies were found at rounded to sub-rounded grains, with medium
identification point number 1 located in East of good sorting. Averaging 5 m in thickness and
the research area. ranging up to 7 m.
This sub facies is associated with other This sub-facies was found at identification
indicators of structured sediment: Gradded point number 2 located in the eastern research
Bedding and coal lenses. The geometry area. This has a sedimentary structure of ripple
Characteristic of this subfacies shows a lamination with a geometry length of 5.2 cm,
monotoneous interbed of massive Siltstone and mostly with medium-grain sandstone which
sandstone with laminae sedimentary structure. was continuous and sinuous. This sub facies is
Anothers we found a sub-facies of monotoneous associated with indicators of sedimentary
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PROCEEDING, SEMINAR NASIONAL KEBUMIAN KE-8
Academia-Industry Linkage
15-16 OKTOBER 2015; GRHA SABHA PRAMANA
structures such as symmetrical ripple and identification point number 3 and 4 be located in
crossbed structures. the Middle part of the research area.
The geometric characteristics of this sub- It shows sedimentary structures of wavy ripple
facies show a channels in outcrop (Tucker, lamination with a geometric length 4.7 cm,
2011) that is influenced from internal mostly with silt clast and very fine sand grain.
(vertical load) and external forces (erosion This sub facies is associated with an indicators
intense). Several beds have interbedded massive of sedimentary structures such as parallel
siltstone and sandstone. lamination with flat bedding, burrow and
Interpretation : According to the properties of muddier lenses.
the textural and structural sedimentary rock, Interpretation : Based on the textural and
this sub-facies represents a medium energy structural sedimentary rock properties, this sub-
deposition of suspension with water (Scholle facies represents a medium energy deposition
and Spearing, 1998) as a sedimentation with a traction bed load mechanism (Scholle
mechanism. This sub-facies is in a difference and Spearing, 1998) as a sedimentation
place than the first sub-facies, it is in the mechanism. This sub-facies is in a different
transition zone of a tide estuary. (Scholle and place from the previous sub- facies. The sub-
Spearing, 1998). Estuary sediment typically facies is in the transition zone (tide estuary,
consists of medium-sorted to well-sorted Scholle and Spearing, 1998). The tide
medium-grain clast to fine-grain clast and shapes the interiors of most estuaries into a
mudstone, two very different types of materials. series of tidal bars and channels. Tidal bars,
The sand may be introduced mostly from the where the sediments are generally sands, may
ocean, while the mud is contributed primarily form complicated and frequently shifting
from river discharge. Commonly, the mud and networks. The structure within in this area
well-sorted sand are interlayered in sharply develops a wavy lamination structure, sinous
contrasting stratum, although intense ripple lamination, and cross lamination (Scholle
bioturbatation may mix the components into a and Spearing, 1998). The depositional
muddy sand or sandy mud (Scholle and environment of this sub-facies is influenced by
Spearing, 1998). The depositional environment the tidal bars of the estuary (Scholle and
of this sub-facies is influenced by the tidal Spearing, 1998).
channel of estuary (Scholle and Spearing, 1998) Outcrop IV :
Outcrop III : Description : We found a sub-facies of trough
Description : We found a sub-facies of thick crossbed sandstone, planar crossbed with or
Flasher lamination fine grain sandstone which is without clay nodule at bottom to middle facies,
associated with laminated fine grain sandstone Laminated siltstone and claystone with or
and thin coal seam and represented by a dark without bioturbation , Interbedded sandstone
color, sharp and planar bed contacts, coarsening with Flasher bedding, and Intercalated sandstone
upwards to a sandstone unit averaging 13.38 m within claystone at top facies. Sedimentary
in thickness and ranging up to 17.9 m. It has structures in the sandstone include ripple
rounded to sub-rounded clasts, with good lamination, wavy, lenticular, and thickening and
sorting. This sub-facies was found in coarsening upwards succession unit averaging
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