SUBSURFACE ANALYSIS OF SUNDALAND BASINS:
SOURCE ROCKS, STRUCTURAL TRENDS AND THE DISTRIBUTION OF
OIL FIELDS
A THESIS
SUBMITTED TO THE GRADUATE SCHOOL
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE
MASTER OF SCIENCE
BY
SWARDHUNI PETHE
DR. RICHARD H. FLUEGEMAN- ADVISOR
BALL STATE UNIVERSITY
MUNCIE, INDIANA
DECEMBER, 2013
Table of Contents
List of Figures ……………………………………………………………………………………………...2
Acknowledgements ………………………………………………………………………………………...4
Introduction ………………………………………………………………………………………………...5
Geology …………………………………………………………………………………………………….8
Basement …………………………………………………………………………………………..9
Tertiary Basins …………………………………………………………………………………...10
Talang Akar Formation ………………………………………………………………………..…11
Air Benakat Formation …………………………………………………………………………..12
Methods …………………………………………………………………………………………………...15
Outline, Data Collection …………………………………………………………………………15
Data Processing …………………………………………………………………………………..16
Results …………………………………………………………………………………………………….18
South Sumatra Basin ……………………………………………………………………………..18
Sunda and Asri Basins …………………………………………………………………………...30
Ardjuna (NW Java) Basin ………………………………………………………………………..38
Discussion ………………………………………………………………………………………………...48
Conclusion ………………………………………………………………………………………………..56
Appendix I ……………………………………………………………………………………………......57
Appendix II ……………………………………………………………………………………………….61
Appendix III ………………………………………………………………………………………………69
References ………………………………………………………………………………………………...78
1
List of Figures
Figure 1 Satellite image of the study area with the wells from Google Earth .............................................. 7
Figure 2 A simple geological map of Sumatra depicting the position of back-arc basins ............................ 9
Figure 3 Structure of the basins and deposition with respect to the deformation of the basement ............. 11
Figure 4 A typical example of the stratigraphic sequence in South Sumatra Basin ................................... 12
Figure 5 Comparison between the stratigraphic sequences in the Sumatra and Java Basins...................... 14
Figure 6 2D Structural contour map of the basement (top)- South Sumatra Basin .................................... 19
Figure 7 3D Structural model of the top of the basement- South Sumatra Basin ....................................... 20
Figure 8 2D Structural contour map of the Talang Akar Formation (top)- South Sumatra Basin .............. 21
Figure 9 3D Structural model of the top of the Talang Akar Formation- South Sumatra Basin ................ 22
Figure 10 2D Structural contour map of the Air Benakat Formation (top) , South Sumatra Basin ............ 23
Figure 11 3D Structural model of the top of the Air Benakat Formation- South Sumatra Basin ............... 24
Figure 12 2D Isopach map- between the top of the Talang Akar Formation (upper surface) to the top of
the basement (lower surface)- South Sumatra Basin .................................................................................. 25
Figure 13 Location map for cross-sections 1 & 2, South Sumatra Basin- South Sumatra Basin ............... 26
Figure 14 Cross section 1- A-A’, N-S, South Sumatra Basin ..................................................................... 27
Figure 15 Cross section 2- B-B’, SW-NE, South Sumatra Basin ............................................................... 28
Figure 16 Structural contour map of the basement (top) showing the distances between the wells and the
grabens- South Sumatra Basin .................................................................................................................... 29
Figure 17 Structural contour map of the basement (top) - Sunda/Asri Basins ........................................... 31
Figure 18 3D Structural model of the top of the basement- Sunda/Asri Basins ......................................... 32
Figure 19 Location map for the cross-sections 1& 2- Sunda/Asri Basins .................................................. 33
Figure 20 Cross section 1- A-A’, General structural trend of the Sunda/ Asri Basins from SW to NE,
Sunda/Asri Basins ....................................................................................................................................... 34
Figure 21 Cross section 2- B-B’, SW-NE, Sunda/Asri Basins ................................................................... 35
Figure 22 Structural contour map of the basement (top) showing the distances between the wells and the
grabens- Sunda/Asri Basins ........................................................................................................................ 37
Figure 23 2D Structural contour map of the basement (top), Ardjuna Basin ............................................. 39
Figure 24 3D Structural model of the top of the basement- Ardjuna Basin................................................ 40
Figure 25 2D Structural contour map of the Air Benakat Formation (top)- Ardjuna Basin ....................... 42
Figure 26 Location map for cross-sections 1& 2- Ardjuna Basin............................................................... 43
Figure 27 Cross section 1- A-A’, W-E, Ardjuna Basin .............................................................................. 44
Figure 28 Cross section 2- B-B’, N-S, Ardjuna Basin ................................................................................ 45
Figure 29 Structural contour map of the basement (top) showing the distances between the wells and the
grabens- Ardjuna Basin............................................................................................................................... 47
Figure 30 Example of wrench faults from Los Angeles Basin ................................................................... 50
Figure 31 Contour map of the basement from Central Sumatra showing NW-SE trending wrench faults 51
Figure 32 Location map of the South Sumatra Basin showing wrench faults ............................................ 52
Figure 33 Index map of the NW Java showing the distribution of the wells in the area. ........................... 55
Figure 34 2D Isopach map of the Air Benakat Formation - South Sumatra
Basin……………………………………………………..………………………………………………...57
Figure 35 2D Structural contour map of the top of the Talang Akar Formation- Sunda/Asri Basins ........ 58
2
Figure 36 2D Structural contour map of the top of the Air Benakat Formation- Sunda/Asri Basins ......... 59
Figure 37 2D Structural contour map of the top of the Talang Akar Formation- Sunda/Asri Basins ........ 60
Figure 38 3D Structural model of the top of the Talang Akar Formation- Sunda/Asri Basins................... 61
Figure 39 3D Structural model of the top of the Air Benakat Formation- Sunda/Asri Basins ................... 62
Figure 40 Location map for cross-section A-A', Sunda/Asri Basins .......................................................... 63
Figure 41 Cross-section 3 A-A', SW-NE, Sunda/Asri Basins .................................................................... 64
Figure 42 3D Structural model of the top of the Talang Akar Formation- Ardjuna Basin ......................... 65
Figure 43 3D Structural model of the top of the Air Benakat Formation- Ardjuna Basin.......................... 66
Figure 44 Location map for cross section 3 A-A', Ardjuna Basin .............................................................. 67
Figure 45 Cross section 3- A-A’, N-S, Ardjuna Basin ............................................................................... 68
3
Acknowledgements
I would like to express my gratitude to my committee chair, Dr. Richard H. Fluegeman for his constant
support and guidance throughout my academic career at Ball State. I would also like to thank my
committee members Dr. Jeffry Grigsby and Dr. Kirsten Nicholson for their support and valuable
suggestions on my thesis. I am very grateful to Dr. William Ade, for providing me the funding to work on
this project and also for his valuable insights.
I want to thank my family and my friend Aneesha Balakrishnan, without whose inspiration, this work
would not have been successful.
4
Introduction
Sumatra is the largest island in Indonesia. On a global scale it ranks 21 st (as of 2011) in oil production.
Most of the Indonesia’s oil is produced from the oil fields of Sumatra. Sumatra is a part of the Sunda shelf
which has been surrounded by the intensely tectonic margins. As a result, a large number of structural
basins have formed on the shelf. These basins act as very good traps for the oil accumulation. Depending
upon the exact location of the basin, source rock and reservoir rock formations may vary although they
are equivalent in age. In this study the focus is on the Talang Akar Formation, which is the source rock in
our study area and the Air Benakat Formation, which acts as a reservoir rock.
The purpose of this study is to verify the Ade observation (Ade, W., pers. comm.) about the oil fields and
structural basins of Sumatra. According to the observation, “95% of all commercial oil fields in the region
occur within 17 km of seismically mappable mature sedimentary rocks in the producing basins”.
Geophysical data available from this region is being used for the analysis of Sumatra basins. This data is
part of the geophysical database of the South East Asia- Pacific region, donated by L. Bogue Hunt;
commonly known as the “LBH Database”. It contains physical, lithological, and paleontological logs,
seismic sections, structural maps and detailed geological reports of many exploration sites.
Sumatra’s oil is sourced from its mature Tertiary back-arc basins. Owing to the subduction zone on the
west of Sumatra, the Sunda shelf underwent extension and rifting, which resulted in the formation of
these basins. North, Central and South Sumatra basins are among the major on-shore basins. According to
Koesoemadinata (Koesoemadinata, 1969) the deposits of the initial transgressive sequence have yielded
large quantities of oil in Sumatra, especially in South Sumatra. Talang Akar Formation is an important
source rock from this sequence. As he has stated, the earliest wells were drilled in the Air Benakat
Formation- part of the regressive sequence- which is a great reservoir for the oil. Among the important
off- shore basins are the Sunda and Asri basins. NW Java basin area is spread both on and off the shore of
Java. All of these basins have numerous sub- basins or individual smaller oil fields.
5
In this study of the Sumatra basins, well log data from the LBH database were used. In order to assess the
basin structures and the distribution of source rock, 2D structural maps of three different units were
created; namely, the Talang Akar and Air Benakat Formations and the basement. Isopach maps provided
the variation in the thickness of the deposition. Most of the data used here is from the explorations
undertaken before 1980. Thus the status of the wells indicated on the maps may have changed. However,
the attempt is made to focus on the areas of known history of production. The validity of the given Ade
observation is tested in this study. It is hoped, that the conclusions of this study will help determine the
extent of the potential area for exploration, surrounding the producing grabens of the Sundaland basins.
6
7
Figure 1 Satellite image of the study area with the wells from Google Earth
Geology
The geology of Sumatra is very complex. It is a good example of subduction-related structural features.
Subduction of the Indian-Australian plate under the Sunda plate and the subsequent tectonics governed
the formation of the rift basins of Sumatra and Java. Sediments are deposited in the back-arc basins
adjacent to the stable Sunda Shelf (Koesoemadinata, 1969). North, Central and South Sumatra are the
three major oil producing basins in Sumatra. Sunda, Asri and NW Java are also very important for their
petroleum production. Although the stratigraphic sequence and depths of the basins vary over this entire
region, the general geology is constant. As a result of the extension of the Sunda shelf, related to the
subduction in the west, back-arc basins were formed between the Mobile belt and the stable Sunda craton
(Clure, 2005). Rifting and subsidence generated many extensive and regional faults. This process resulted
in the formation of grabens that were filled with deposits during the Tertiary (Fig. 2). Folding of strata at
the end of the Tertiary may have further changed the structural complexity of the basins
(Koesoemadinata, 1969). On maturation these basins became an important site of petroleum generation in
Indonesia. The source rock, Talang Akar Formation, is of late Oligocene to early Miocene age. Whereas
the reservoir forming Air Benakat Formation was deposited during mid to late Miocene.
8
Figure 2 A simple geological map of Sumatra depicting the position of back-arc basins (Barber,
Crow, & Milsom, 2005)
Basement
Basins in Sumatra and Java are mainly Tertiary, lined by the pre-Tertiary crystalline basement rocks. The
basement is comprised of mostly igneous and metamorphic rocks and occasionally sedimentary rocks
toward eastern Indonesia, as observed from the well logs. Rifting that resulted in the depositional basins
took place during Tertiary. Basement rocks were highly deformed into horst and graben structures. Major
rifts were formed trending NE-SW on the Sunda shelf (Clure, 2005)
9
Tertiary Basins
The rifting phase began in early Tertiary and continued until late Oligocene-early Miocene. During this
period, structural grabens were formed and filled by the deposition of fluvio-deltaic sediments (Doust &
Noble, 2008). The major basins contain transgressive and regressive facies that provide the source rocks
and the reservoir rocks respectively (Fig. 3).
For the purpose of this project, two formations were studied in particular; Talang Akar and Air Benakat
Formations. These are very important formations in Sumatra and Java. It is a petroleum system where the
Talang Akar Formation is the source rock and Air Benakat Formation is the reservoir. Since there are
numerous basins in this region that are separated from each other, different formations or petroleum
systems may exist, where the source rocks and the reservoir rocks belong to a different stratigraphic
sequence. Therefore to simplify the data, such formations were grouped with the Talang Akar Formation
or the Air Benakat Formation, based on their equivalent age.
10
Figure 3 Structure of the basins and deposition with respect to the deformation of the basement
(Barber & Crow, 2005)
Talang Akar Formation (TAF)
Talang Akar was deposited as a transgressive sequence during late Oligocene and very early Miocene. It
overlies the basement rocks. In some basins Talang Akar may be underlain by other formations; such as
lacustrine deposits of Lemat and Lahat Formations in South Sumatra and Jatibarang Volcanics in
Jatibarang basin of NW Java. Talang Akar is comprised of fluvio-deltaic fine shales and silts as well as
sands. Some of the sands deposited in near-shore marine environment are fairly porous and permeable
and contain oil in the stratigraphic and fault-related traps (Doust & Noble, Petroleum systems of
Indonesia, 2008). Thickness varies from the basin to basin, but this formation can be as thick as 7000 feet
(2133.6 m) in the deepest parts of the basin. Intermittent coal seams are also found, which may act as a
source of hydrocarbons. Lower unit of the Talang Akar Formation is known to produce good quality oil
in more quantities than that of the upper unit (Koesoemadinata, 1969). The shales of Menggala and
Pematang Formations from Central Sumatra were included as equivalents to the Talang Akar Formation.
11
Figure 4 A typical example of the stratigraphic sequence in South Sumatra Basin (Clure, 2005)
Air Benakat Formation (ABF)
The Air Benakat Formation is a thick sequence of sands deposited in a regressive system. It is comprised
of several units of marine sandstones from deep to shallow marine environment. Air Benakat was
deposited during middle to late Miocene, when the rifting phase was over. Since it was deposited as part
of the regressive marine sequence, the shallower deposits of Air Benakat have broader distribution. It is
the main reservoir rock in the South Sumatra basin. Its average porosity is about 25% (standard range for
a sandstone is 5-25%) which makes it an excellent reservoir rock (Bishop, 2001). In parts of South
Sumatra, the lower Palembang Formation is equivalent to the Air Benakat (Fig. 5). In NW Java Basins,
the “Main” and “Massive” intervals of the Cibulakan Formation are equivalents of the Air Benakat
Formation (Fig. 5). The Main and Massive are thick sand deposits as thick as 3000 feet (914.4 m). They
12
are comprised of the lowstand, transgressive and highstand intervals. Since the shallow marine sediments
tend to be coarse, they have better porosity. The lowstand sands have an average porosity of 27% and
have a very good reservoir quality compared to the transgressive and highstand sands (Purantoro,
Butterworth, Kaldi, & Atkinson, 1994). The Cibulakan Formation is deposited across Ardjuna and
Jatibarang sub-basins of the NW Java.
13
14
Figure 5 Comparison between the stratigraphic sequences in the Sumatra and Java Basins (Doust
& Noble, 2008)
Methods
Outline
A vast amount of data is available to us in the form of well logs and seismic sections from various oil
fields of Indonesia. They provide us the basement depths and the depths to the rock formations of our
interest. This stratigraphic data is combined with the geographical locations to produce the stratigraphic
and structural maps. Profiles for the individual wells were created in the geophysical software called
“RockWorks”. It allows us to manage stratigraphical data, the production status of the wells and the
location. After determining the UTM coordinates and project dimensions in the software, structural and
isopach maps for the entire study area were created. In addition to the maps, several cross sections and 3D
structural models were created to understand the basin structure in a better way. The maps, and the cross
sections, are useful to analyze the position of producing oil fields with respect to the structural features.
The wells with good show of oil were chosen for drawing the cross sections.
Data collection
The geophysical data on South East Asia is available to the Ball State University’s Department of
Geological Sciences, as the LBH database. It includes topographic maps and subsurface profiles, obtained
from seismic, resistivity, gamma ray methods etc., as well as detailed geological reports of several oil
fields. The main focus of this study is on south Sumatra and northwest Java, Indonesia. Therefore the data
representing the oil fields in Sumatra were chosen specifically. This data set has well logs based on
electrical resistivity, gamma ray, spontaneous potential and lithology. These logs are important as they
contain the location of the well and the depths of the specific geologic formations.
In order to utilize this data and make meaningful interpretations, it is necessary to create extensive
geological maps. RockWorks is a powerful software package that allows such data processing and can
handle large databases. A database was compiled in an Excel spreadsheet, including the information such
as well location, elevation, total depth. The depths to the tops and bottoms of both Formations (Talang
15
Akar and Air Benakat) and the depth to the top of the basement were entered manually after the
spreadsheet was imported into the software. Appropriate symbols were chosen to indicate the status of the
wells in terms of production. Some of the once-producing wells drilled in 70’s and 80’s may not be in
production today, but they are in the potentially productive oil fields; hence important. Structure of the
basement is important in order to determine the basin boundaries; therefore dry holes were equally
important in order to obtain the depth of the basement. Formation tops in all the well logs were not
marked. If they were missing, they were determined by comparing those logs with other logs or seismic
sections from the same field or basin. Depending on the area or the basin, formation names may vary. In
that case, their equivalents from the local stratigraphic sequence were used.
Data Processing
It is important to use the same units for all the maps and figures. Elevation and depths were maintained in
feet. The geographical coordinates found on the well logs are in the form of degrees, minutes and
seconds. They were converted into the decimal degree (DD.ddddd) using software called Garmin. This is
the acceptable format for RockWorks. All the latitude figures for the wells in the southern hemisphere
were given a negative value. A spreadsheet containing well name, location, elevation, and total depth, was
imported into RockWorks and each borehole entry was attributed with the formation depths and the
well’s production status using appropriate symbols. Once all the data were entered into the software, the
next step was to convert all the latitude and longitude figures from decimal format into the UTM (meter)
system. It was done by a simple inbuilt menu option. Since most of the wells in were located in the south
of the equator; UTM zone 48S (S for the southern hemisphere) was assigned to the database. Computing
the project dimensions was the last step before creating various types of maps.
Simple menu functions allowed the creation of a variety of maps, such as the structural maps of basement,
Talang Akar and Air Benakat Formations. These maps are based on the given depth measurement of the
individual wells. 2D isopach maps are particularly useful when we need to evaluate the thickness of a
Formation. These isopach maps were produced for the Talang Akar and Air Benakat Formations. Since
16
the Talang Akar overlies the basement in most case; the top of the basement was used as a lower surface
to indicate the thickness in the isopach maps of the Talang Akar Formation. This is a good way to observe
the sedimentary deposition with respect to the basement structure. Every map contains 1) the well
locations that are denoted by their status symbol, and 2) appropriate legend. Vertical profiles or cross
sections were also produced to better understand the basement structure. Contour interval (CI) for the
structural contour maps and the isopach maps is 500 feet.
The goal of this study is to find out if the oil fields are situated within a 17 km distance from the grabens;
therefore, only the producing wells and the wells with a good show of oil were treated as potential fields.
The wells with an unknown status were not considered while measuring the distances, since the
information pertaining to the show of oil was unavailable. To measure the distances between the wells
and the grabens, structural contour maps of the basement were used. Based on the density of the contours,
margins of grabens were determined for every basin. Using Microsoft Excel, percentage and the average
number of wells situated within a 17 km margin were calculated.
Table 1 Well status symbols
Symbol
Status
Unknown
Dry hole
Oil show
Gas show
Oil & gas show
Oil well
Gas well
Oil & gas well
Suspended oil well
17
Results
The maps described in the results are very large scale maps. The individual clusters of the wells are
actually several smaller oil fields or basins. Fault lines are included in the structural maps and 3D models.
The whole study area has been divided into three separate basin areas; South Sumatra, Sunda/Asri and
NW Java. For the well status symbols used in the maps and the cross sections refer to Table 1 in the
Appendix III. More maps, 3D structural models and cross sections are given in Appendices I and II.
South Sumatra Basin
Figure 6 is a structural map of the basement in South Sumatra Basin area. The depth of the basement
based on the data points ranges from 1000 (304.8 m) to 10,000 feet (3048 m) below sea level and more
commonly from 3000 to 7000 feet (914.4-2133.6 m) below sea level. Most of the producing wells are
situated in the deeper parts of the basin. In the upper half of the map there is a group of wrench faults. The
South Sumatra Basin is deeper towards its south end.
18
Fault; arrow
points the
downthrow side
Strike slip
Figure 6 2D Structural contour map of the basement (top), CI= 500ft (152.4m)
19
Figure 7 gives a better idea of the basement structure. Comparison of Fig. 6 to this 3D model shows that
the producing wells are situated in the grabens or on their flanks. Towards the south, the basement is as
deep as 10,000 feet (3048 m).
Depth
(feet)
Distance
(meters)
Figure 7 3D Structural model of the top of the basement
20
The structure of the Talang Akar Formation in Fig. 8 is consistent with the structure of the basement.
Location of the deep troughs and highs matches in both the maps (Fig. 6 & 8). Comparing these two
maps, the thickness of Talang Akar appears to be approximately 1000 to 5000 feet (304.8- 1524 m).
Study of the isopach maps will confirm this observation.
Fault; arrow
points the
downthrow
side
Strike slip
Figure 8 2D Structural contour map of the Talang Akar Formation (top), CI= 500ft (152.4m)
21
Based on the 3D model of the Talang Akar Formation (Fig. 9), general trend of the grabens seems similar
to that in Fig. 7. The deep graben in the south, as seen in the structural model of the basement (Fig. 7),
appears shallower in Fig. 9; suggesting that it was filled heavily with sediments.
Depth
(feet)
Distance
(meters)
Figure 9 3D Structural model of the top of the Talang Akar Formation
22
The structure of the Air Benakat Formation in Fig. 10 is somewhat similar to that of the Talang Akar
Formation in Fig. 8; especially in the lower half of the map. However, Air Benakat does not directly
overlie the Talang Akar Formation.
Fault; arrow
points the
downthrow
side
Strike slip
Figure 10 2D Structural contour map of the Air Benakat Formation (top), CI= 500ft (152.4m)
23
In Fig. 11 depth to the top of the Air Benakat Formation varies by 5000ft (1524m).
Depth
(feet)
Distance
(meters)
Figure 11 3D Structural model of the top of the Air Benakat Formation
24
This map (Fig. 12) has been created using top of the Talang Akar Formation as the upper surface and
basement as the lower surface. In most of the logs that represent the wells in this map, Talang Akar lies
directly above the basement. The area represented by purple indicates the thickness of 0 to 1000 feet (0304.8 m). These are in fact the deep grabens.
Thickness
in feet
Figure 12 2D Isopach map- between the top of the Talang Akar Formation (upper surface) to the
top of the basement (lower surface), CI= 500ft (152.4m)
25
Figure 13 is the Location map of the wells in South Sumatra Basin displaying the section lines A-A’ and
B-B’.
A’
A
Figure 13 Location map for cross-sections A-A’ and B-B’, South Sumatra
Basin, Distances in meters
26
Cross section A-A’ passes through three producing wells from different oil fields. The wells on both ends
are situated on the flanks of grabens (Fig. 6); however, the one in the middle is situated in the graben. The
isopach map in Fig. 12 clearly shows this middle part of the area where the Talang Akar Formation is
thicker. All cross sections in this study exhibit the interpolated surfaces of the Talang Akar Formation,
Air Benakat Formation and the basement. For more detailed stratigraphic column, refer to Fig. 5.
Figure 14 Cross section A-A’, SW-NE displaying the structural trends in Talang Akar Formation
(TAF), Air Benakat Formation (ABF) and the basement.
27
In Fig. 15, note that the producing well in the center of the cross section B-B’ (Fig. 15) is situated where
the Talang Akar Formation is shallower than the surrounding area. Also, the well on the right end of the
section is a producing well, situated further inside the graben. This elevated structure of the Talang Akar
Formation is clearly visible in the 3D model (Fig. 9) towards east.
Figure 15 Cross section B-B’, N-S displaying the structural trends in Talang Akar Formation
(TAF), Air Benakat Formation (ABF) and the basement. Producing wells situated on the flanks of
the grabens as well as in the middle of the graben.
28
In Fig. 16, the contour line of -4000 feet (-1219.2m) was chosen as the graben margin, based on the
contour density and basin slope (Fig. 7). The average distance between the oil fields and the nearest
grabens is 18.31 km. Out of 36 potential oil fields only 28, i.e. 77.78% of the fields lie within the 17 km
distance from the grabens.
Fault; arrow
points the
downthrow
side
Strike slip
Figure 16 Structural contour map of the basement (top) showing the distances between the wells
and the grabens, CI= 500ft (152.4m)
29
Sunda and Asri Basins
There are two basins in the following map (Fig. 17). The one on the west is the Sunda basin; while Asri
basin is in the NE part of the map. They are controlled by major faults (Doust & Noble, 2008). The
producing wells in the Sunda basin clearly lie in the vicinity of the fault-bound grabens.
30
Fault; arrow
points the
downthrow side
Figure 17 Structural contour map of the basement (top) - Sunda/Asri Basins, CI= 500ft (152.4m)
31
The overall shape of the Sunda and Asri basins is visible in the 3D model in Fig. 18. They are separated
by a ridge, trending approximately north-south.
Depth
(feet)
Distance
(meters)
Figure 18 3D Structural model of the top of the basement- Sunda/Asri Basins
32
Figure 19 is the Location map of the wells in Sunda and Asri Basins displaying the section lines C-C’ and
D-D’.
C’
D’
D
C
Figure 19 Location map for the cross-sections C-C’ and D-D’- Sunda/Asri
Basins, Distances in meters
33
Cross section C-C’ in Fig. 20 shows the general structural trend of the basins in southwest-northeast
direction. From left to right, the line C-C’ crosses the Sunda and Asri basins. Both basins are very close to
each other and have a series of grabens of varying depths. For more detailed stratigraphic column, refer to
Fig. 5.
Cross section C-C’
C
C’
Figure 20 Cross section C-C’, displaying the structural trends in Talang Akar Formation (TAF),
Air Benakat Formation (ABF) and the basement. General structural trend of the Sunda/ Asri
Basins from SW to NE, This is a modeled cross section created by incorporating the depths of the
closest wells.
34
The cross section in Fig. 21 shows that the producing wells are situated on the basement high or flanks of
the adjacent grabens. This is also the area where most of the producing wells are located according to the
structural map of the basement in Fig. 16.
Cross section D-D’
D
D’
Figure 21 Cross section D-D’, SW-NE displaying the structural trends in Talang Akar Formation
(TAF), Air Benakat Formation (ABF) and the basement. Location of the wells on the horsts is
noticeable.
35
In Fig. 22, the distances from the nearest graben were measured for several wells on a structural map of
the basement, using a measurement function in the RockWorks. On observing the density of the contours,
the contour line of -5000 feet (-1524 m) was determined to be the margin of the grabens. There are total
23 potential oil fields in this map. Three of them lie outside the grabens, but within a 17 km margin. The
distance of the oil fields from the grabens ranges from 8 to 12.6 km; averaging 10.49 km.
36
Fault; arrow
points the
downthrow side
Figure 22 Structural contour map of the basement (top) showing the distances between the wells
and the grabens, CI= 500ft (152.4m)
37
Ardjuna (NW Java) Basin
Ardjuna Basin (Fig. 23) is located in the west of the NW Java Basin area. Wells in this basin are some of
the deepest and highly producing in Indonesia. Fig. 23 shows three of the major faults that separate the
grabens. Depth to the basement ranges from 3000 (914.4 m) to 9000 feet (2743.2 m) below the sea level.
2D structural map (Fig.23) of the Ardjuna Basin shows that there is a series of grabens trending N-S or
NE-SW and varying in the depth. It continues towards Jatibarang Basin in the east, where more fault
bound grabens are situated. From the distribution of the producing wells, the oil fields in this basin
occupy the area between these large grabens (Fig. 23).
38
39
Figure 23 2D Structural contour map of the basement (top), CI= 500ft (152.4m). Note the three faults in
the center of the map.
Fault; arrow
points the
downthrow side
The number of producing wells increases from blue to green area on the structural map in Fig. 23. As per
the 3D model (Fig.24), depth of the basin decreases in the same area. This observation is very similar to
that of the Sunda and Asri basins; where the most producing wells are situated on the flanks of the
grabens.
Depth
(feet)
Distance
(meters)
Figure 24 3D Structural model of the top of the basement- Ardjuna Basin
40
In Fig. 25, depth to the top of the Air Benakat Formation ranges from 1200 (365.76 m) to 4800 feet
(1463.04m) below sea level; although most of the production appears to be in the area (marked in green),
where the depth is 2400 (731.52 m) - 3200 feet (975.36 m) below sea level.
41
42
Figure 25 2D Structural contour map of the Air Benakat Formation (top), CI= 500ft (152.4m)
Fault; arrow
points the
downthrow side
Figure 26 is the location map of the wells in Ardjuna (NW Java) Basin displaying the section lines for the
cross sections E-E’ and F-F’
F
E
E’
F’
Figure 26 Location map for cross-sections E-E’ and F-F’- Ardjuna Basin, Distances in meters
In Fig. 27, there is a gradual change in the depth of the basement and it becomes shallower from west to
east. The alignment of the three faults (Fig. 22), marked by the change in the depth is apparent in the
cross section (Fig. 27).
43
44
E
Figure 27 Cross section E-E’, W-E displaying the structural trends in
Talang Akar Formation (TAF), Air Benakat Formation (ABF) and the
basement. The wells are located between the faults.
Cross section E-E’
E’
Figure 28 is displays the structure of the Ardjuna basin in north-south direction. The drop in the basin
depth is consistent with that in the structural map of the basement (Fig. 23) and the 3D model (Fig. 24).
The well in the middle has a good show of oil and it is situated where the basement is higher than the
areas immediately next to it.
Cross section F-F’
Figure 28 Cross section F-F’, N-S displaying the structural trends in Talang Akar Formation
(TAF), Air Benakat Formation (ABF) and the basement. The producing well in the middle of the
section is situated on the flank of the graben, as seen in the structural contour map of the basement
(Fig. 23). On the left of section F-F’, ABF is interpolated by the software and crosses the TAF;
however, it is absent in that location and has an onlap.
45
In Fig. 29, the contour line of -5000 feet (-1524 m), seen as a break between yellow and green colors, was
established as a margin for the grabens. Wells PSI Z, PSI PZ, Dempo 1, Rinjani and Soputan are not part
of the Ardjuna basin; however, they were included to provide a better perspective of the area. The
distance between the producing wells and the graben ranges from 0.5 to 20.6 km, with an average of
10.12 km. Out of 47 potential oil fields, 43, i.e. 92% fields are situated within 17 km from the grabens.
46
47
Figure 29 Structural contour map of the basement showing the distances between the wells and the grabens,
CI= 500ft (152.4m)
Fault; arrow
points the
downthrow side
Discussion
As evident from the maps, the wells are concentrated inside or around the basins; especially the ones that
have production potential. Basins on the Sunda Shelf are roughly NE-SW oriented and are fault bound.
Folding of the Sunda Shelf on the east of the Subduction zone has generated numerous small and large
faults that are parallel to the strike of folding.
Concentration of the data points in parts of the maps makes the basins appear merged. To resolve this
problem, the maps were broken down in several separate regions; focusing on a small slice of the
longitudinal area at a time. The first section comprised of the South Sumatra Basin (Fig. 6). The second
section contains the Sunda and Asri Basins (Fig. 17) while the third section includes the NW Java Basin
area (Fig. 23). Results obtained this way contain more defined basin boundaries and more pronounced
structural features.
Structural basins of Sumatra and Java are fault basins. Most of the producing basins of this region lie
northeast of the mobile belt. Important producing wells of Sumatra and Java are in the central and south
Sumatra, Sunda, Asri and Northeast Java basins. The Talang Akar Formation is a major source of
petroleum in the basins of Sumatra. These fine shales are deep seated fluvio-deltaic sediments that were
deposited during the rifting phase (mid Eocene- early Miocene) of the Sunda craton (Doust & Noble,
Petroleum systems of Indonesia, 2008). In central Sumatra they are replaced by the Brown Shale Member
of the Pematang Formation. In the basins of NW Java, the reservoir rocks equivalent to the Air Benakat
Formation are the Main/ Massive sands of the Cibulakan Formation. When the rifting phase was over, the
deep grabens were heavily filled in by marine sediments (Purantoro, Butterworth, Kaldi, & Atkinson,
1994). In off-shore Java basins on the shelf, a thick marine sequence of the Air Benakat/ Cibulakan
Formations acts as a very good reservoir rock.
48
South Sumatra Basin
Although wells with a good show of oil are situated in the deeper parts of the South Sumatra Basin;
several producing wells are situated on the flanks of the grabens and on the horsts (Fig. 6 &15).
Correlation of these wells with other wells in the same or adjoining fields shows that the sequence of
deposition and age of the formations are equal. Therefore, it is evident that the faulting or uplifting
occurred after the sediments were deposited in the respective basins. This observation can be supported
by the fact that the Talang Akar Formation was deposited during the ‘postrift’ phase when the region was
undergoing tectonic movements and structural changes (Doust & Noble, 2008).
A paper by T. P. Harding, “Petroleum Traps Associated with Wrench Faults” (Harding, 1974) talks about
the importance of wrench faults in petroleum trap formation. In a region influenced by high tectonic
activity, intense folding and faulting produces very complex structures such as wrench faults. The
complexity of these structures is due to their intersecting strike-slip, normal and reverse faults. Due to
this, the rock strata are offset and the structural traps are formed. Comparing the folds, faults and the
basin structures in Sumatra to this model, the wrench faults appear to be a common feature in the basins
of Sumatra.
Maps of various oil fields in central and south Sumatra indicate the position of oil fields dispersed in
between the wrench faults. These faults are situated on the eastern side of the geanticlinal belt that runs
along the length of Sumatra. This folding of the pre-Tertiary and Tertiary rocks and the subsidence of
basins could be part of the developmental history of these wrench faults. Fig. 30 is an image from the
literature (Harding, 1974) that represents a typical wrench fault system from the Los Angeles Basin. The
fault structures in this image are similar to those from the structural map (Fig. 31) from the database and
location map of the South Sumatra Basin (Fig. 32). This correlation provides a clue to the possible
location for the exploration.
49
Figure 30 Example of wrench faults from Los Angeles Basin (Harding, 1974). Notice the
intersecting faults.
50
Figure 31 Contour map of the basement from Central Sumatra showing NW-SE trending
wrench faults from LBH database.
51
Depth
in feet
Fault; arrow
points the
downthrow
side
Strike slip
Figure 32 Location map of the South Sumatra Basin showing wrench faults
Another paper (Ryacudu, Djaafar, & Gutomo, 1992) states a similar observation about the North Sumatra
Basin. The wrench faults in this basin provide a path of migration for oil. These papers and the study of
the structural maps from the LBH database, suggest that the wrench faults form good structural traps.
Therefore, more emphasis should be given on identifying the wrench faults during future exploration.
The deposits of the Talang Akar Formation lie deep into the grabens directly above the basement rocks;
except when it is underlain by Lemat/ Lahat Formations. Therefore, in the isopach map of the Talang
Akar Formation (Fig. 12), areas of less thickness represent the grabens. Oil fields often coincide with
these areas. In the structural map of Air Benakat Formation the producing oil fields fall into an area where
52
Air Benakat Formation is shallow, i.e. approximately -3000 to -5000 feet (914.4-1524 m). Shallower
depth makes it easy to access the reservoir due to which the earliest production came from the shallower
wells (Koesoemadinata, 1969).
Sunda and Asri Basins
Figure 17 is a contour map of the basement from the Sunda and Asri Basins. The two basins are bound by
faults on their eastern flank. The map and the 3D model (Fig. 18) of the basement give a clear
understanding of its structure.
The Sunda and Asri basins are situated in a wedge between Sumatra and Java islands. As of 1997 the oil
reserves of these basins were expected to be 1500 MMbo (Doust & Noble, 2008). There are closely
spaced grabens up to 7000 feet (2133.6 m) deep, clearly seen in the 3D model (Fig.18). Based on the well
data, the source rock- reservoir system in these basins appears to be Talang Akar- Air Benakat/ Batu Raja.
Batu Raja is a reef formation that acts as a good reservoir at many sites in Sumatra- Java. Cross sections
(Fig. 20 & 21) constructed through Sunda/ Asri neatly display the location of wells in relation to the
structure of the grabens. Most of the producing wells are located on the flanks, in shallow areas of the
grabens. This observation is consistent with previous research in the Sunda and Asri basin area (Doust &
Noble, 2008). The average distance between the wells and the producing grabens is 10.49 km; which is
within the 17 km margin described in the Ade observation.
Northwest Java Basin Area- Ardjuna Basin
Another example of a typical structural basin on the Sunda Shelf is the Northwest Java Basin area. The
LBH database contains a large amount of well data from this area. Ardjuna and Jatibarang are the major
basins in the northwest Java area. Oil fields in the western part of this area belong to the Ardjuna Basin
(Doust & Noble, 2008). The source rock in Ardjuna Basin is Talang Akar. In the NW Java area, Talang
Akar Formation is underlain by Jatibarang volcanics (Atmadja & Noeradi, 2005). Well logs show that in
some of the sections, the Talang Akar Formation contains layers of coal which is an important source of
53
hydrocarbons as found in south Sumatra basin area (Davis, Noon, & Harrington, 2007). Although Air
Benakat Formation is not present in this basin area, its equivalent Main/ Massive sands act as reservoirs.
These are thick sands deposited during the marine regression. Lowstand intervals of the Main sands have
good porosity and permeability which make them good reservoir rocks (Purantoro, Butterworth, Kaldi, &
Atkinson, 1994). Well logs indicate a good show of oil as well as gas in the Main and Massive sands.
These sands can be as thick as three thousand feet. The clusters of wells occur between the N-S and NESW trending series of faults. Jatibarang basin is slightly east of the Ardjuna basin. These sand units also
occur in the Jatibarang basin of NW Java. Here they are part of the Cibulakan Formation and given as the
upper Cibulakan Member in the well logs. As these sands were deposited toward the end of regression,
they are thinner toward the basin walls. This affects the resulting structural and isopach maps where the
grabens do not appear prominent. This error was compensated by manually constructing the fault lines
based on the available maps from the literature and database (Doust & Noble, 2008).
Figure 29 is a structural map of the basement for the Ardjuna basin. The segments were drawn to measure
the distance between the wells and the margins of the nearest grabens. As mentioned in the results, the
average of this distance is 10.12 km. It is less than 17 km and thus, concurrent with the Ade observation.
The actual number of oil fields and producing wells is greater than the number of wells shown in the
structural map (Fig. 29). That could have lowered the percentage of wells occurring within the 17 km
margin. Figure 33 is an index map of the northwest Java, showing the distribution of wells in the area. A
large number of those wells are producing wells. Hence, the actual percentage of producing fields within
17 km from the grabens could be equal to or greater than 95, for the Ardjuna Basin.
54
55
Figure 33 Index map of NW Java showing the distribution of the wells in the area.
Conclusion
In the South Sumatra Basin, 77.78% of the oil fields are located within 17 km of the producing grabens;
with an average distance of 18.31 km.
In the Sunda and Asri Basins, all of the oil fields occur within 17 km distance from the producing
grabens; with an average distance of 10.49 km.
In the Ardjuna Basin area of the northwest Java, 92% of the oil fields lie within 17 km of the producing
grabens; with an average distance of 10.12 km.
The results of this study indicate that the Ade observation, “95% of all commercial oil fields in the
Sumatra region occur within 17 km of seismically mappable structural grabens in the producing basins” is
true for the Sunda/Asri Basins. Given the high percentage of data being in the hypothesized distance
range, further study of the individual oil fields and recent data may yield similar results for the Ardjuna
Basin. The well data used for the South Sumatra Basin in this study is not uniformly distributed. Hence,
definite conclusions as to what factors control the regional structures, cannot be drawn. Therefore, it is
necessary to study the individual oil fields using seismic surveys and well data in order to establish a
relationship between the structural features and the oil production.
The structural maps and cross sections indicate that the flanks of the grabens or the horst region may
prove to be the potential sites for future exploration. Comparison between the obtained maps and those
from the literature suggests that the wrench faults provide good oil traps and may be the potential sites for
the exploration as well.
56
Appendix I: Structural and isopach maps
South Sumatra Basin
Thickness
in feet
Figure 34 2D Isopach map of the Air Benakat Formation, CI= 500ft (152.4m)
57
Sunda/ Asri Basins
Fault; arrow
points the
downthrow side
Figure 35 2D Structural contour map of the Talang Akar Formation (top), CI= 500ft (152.4m)
58
Fault; arrow
points the
downthrow side
Figure 36 2D Structural contour map of the Air Benakat Formation (top), CI= 500ft (152.4m)
59
60
Figure 37 2D Structural contour map of the Talang Akar Formation (top), CI= 500ft (152.4m)
Ardjuna (NW Java) Basin
Fault; arrow
points the
downthrow side
Appendix II: 3D models and cross sections
Sunda and Asri Basins: 3D Structural models
Depth
(feet)
Distance
(meters)
Figure 38 3D Structural model of the top of the Talang Akar Formation- Sunda/Asri Basins
61
Depth
(feet)
Distance
(meters)
Figure 39 3D Structural model of the top of the Air Benakat Formation- Sunda/Asri Basins
62
Sunda and Asri Basins: Cross Sections
Figure 39 is the location map of Sunda/Asri Basins displaying the section line for cross section 3
Figure 40 Location map for cross-section A-A'- Sunda/Asri
Basins, Distances in meters
63
Cross section G-G’
G
G’
Figure 41 Cross-section 3 G-G’, SW-NE displaying the structural trends in Talang Akar Formation
(TAF), Air Benakat Formation (ABF) and the basement.
64
Ardjuna (NW Java) Basin: 3D structural models
Depth
(feet)
Distance
(meters)
Figure 42 3D Structural model of the top of the Talang Akar Formation- Ardjuna Basin
65
Depth
(feet)
Distance
(meters)
Figure 43 3D Structural model of the top of the Air Benakat Formation- Ardjuna Basin
66
Ardjuna (NW Java) Basin: Cross sections
H
H’
Figure 44 Location map for cross section H-H’, Ardjuna Basin, Distances in meters
67
Cross section H-H’
H
H’
Figure 45 Cross section H-H’, N-S displaying the structural trends in Talang Akar Formation
(TAF), Air Benakat Formation (ABF) and the basement.
68
Appendix III: Tables
Tables 2, 3 and 4 show the measured distances between the producing wells and the grabens, for the
South Sumatra, Sunda/Asri and Ardjuna Basins respectively.
Table 2 Distance measurement table for the South Sumatra Basin
Distance in km
Rimbabat 2
32.066
Bulian
18.498
Bentajan 10
20.413
Bentajan 8
25.042
Bentajan 9
28.336
Bentajan 11
26.682
North Kluang 41 1.88
Jemakur
6.637
Kerang 1
12.875
Kerang 2
12.728
Kerang 3
13.085
Tabuan 1
21.663
Tabuan Selatan 18.190
Average
18.315
Table 3 Distance measurement table for the Sunda and Asri Basins
Distance in km
Lestari 1 12.611
Nurbani 3 10.783
PSI ZUD 8.088
Average 10.494
69
Table 4 Distance measurement table for the Ardjuna (NW Java) Basin
Distance in km
PSI FT1 8.169
PSI FT4 6.336
PSI OV
9.184
PSI OY
3.772
PSI XW 2.000
PSI XW3 2.620
PSI X3
9.235
PSI GG3 11.733
PSI WG 14.321
PSI P6
20.656
PSI P11 18.228
PSI P2
20.613
PSI P10 19.331
PSI ML
5.216
PSI MV
0.447
Average 10.124
Table 5 Well log data
Bore
Abab
Asri 1
Astari
Bakung
Bakung(stanvac)
Banuwati 2
Bentajan 10
Bentajan 11
Bentajan 12
Bentajan 8
Bentajan 9
Bentu 2
Berlian 1
Besai 1
Betara
Budiarti 1
Budiarti 2
Buka
Longitude Latitude Elevation Total Depth
104.15694 -3.21667
46
5862
106.88333 -4.73333
56
10377
106.83737 -4.40866
-70
3019
108.88906 -6.37009
69
4115
104.19750 -2.16972
-3
3875
106.43291 -5.04110
-72
9787
104.08028 -2.37139
68
4198
104.13250 -2.40833
30
4230
104.09056 -2.40222
14
4370
104.12069 -2.40014
51
5498
104.13583 -2.40833
67
4549
101.56566 -0.36438
11
4600
106.67953 -4.45599
-71
3235
104.68798 -4.53368
278.2
4069.55
103.41028 -1.13056
65.6
5065.6
106.14750 -5.35194
-101
4069
106.14801 -5.28423
-72
6051
103.41042 -3.45599
292
3867
70
Bulian
Bunga
Candi(Tjandi)1
Capang
cecilia 1
cicih
Cikarang
Cilamaya Timur
Cimalaya Utara 2
Cinta
104.06639
104.17038
104.05194
105.12930
106.33431
106.35159
107.19322
107.56657
107.50939
106.2578
-2.32139
-2.75405
-3.33306
-4.76131
-5.06072
-4.75007
-6.19252
-6.20976
-6.22392
-5.46236
86
21
151
100.4
-85
-83
55.77
6
10
-125
4492
3178
7847
1875
8331
6861
8717
8258
7994
3530
Ciwaringin
Cory
Darmi 1
Dedeh 1
Dempo 1
Dewi selatan 1
Djambu 1-28
Elly 1
Emi 1e
Enny 1
Erna 1
Esi
Fanny
Farah 3
Farah 5
Flora
Gaby 1
Gajah 1
Gayatri 1
Gede
Gita 6
Gita A-7ST2
GN1
Grissik 37
Hariet 1
Harimau 1
Harimau 2
Harimau 3
Harimau 3A
Harimau 4
Harimau 6
Harimau 7
107.32912
106.40111
106.18335
106.48958
108.35266
106.71972
102.20639
106.11091
106.44772
106.26847
106.77222
106.73473
106.41070
106.24150
106.26213
106.63851
106.74524
106.80778
106.30139
106.11514
106.37922
106.37906
107.26784
103.96222
106.79158
104.18931
104.19980
104.19966
104.19944
104.20572
104.20502
104.21046
-6.39173
-4.84444
-4.76803
-4.75994
-5.53079
-4.58083
-1.33778
-5.42401
-5.38778
-4.48431
-4.95194
-4.62814
-5.21812
-5.09991
-5.10946
-4.51769
-4.65217
-2.48556
-4.55333
-5.16817
-5.37000
-5.36972
-5.36129
-2.30861
-4.66655
-3.59247
-3.58907
-3.59953
-3.59972
-3.59440
-3.59043
-3.58073
156
-63
-68
82
82
-63
207
-81
117
54
-72
-71
-74
-90
-87
-70
-80
172
34
-72
-116
-114
79
56
-72
146
99
115
115
123
119
81
8080.7
6877
3912
4500
4500
5977
3389.108
3979
5497
4098
3463
7153
11213
5530
6577
3216
7761
5243
4311
4780
6217
7874
3481
6393
10133
7754
7611
7655
7643
7815
7621
7409
71
Harimau 9
Hatty 1
Hera 1
Herawati 1
Ibul 1
Ibul 2A
Ida 1
Ina 1
Indah
Intan
Ira
Irma
Jambu
Jangga
Janti2
Jemakur
Judy
Kapas Strat 1
Karlina
Kartika
Kartini 1
Kartini 2
Kartini 3
Kartini 4
Kartini 5
Kartini Utara
Katomas
Kejumat
Kemala
Kerang 1
Kerang 2
Kerang 3
Ketaling 1
Kijang
Kitty
KMM1
Krisna 1
Krisna 12
KRK 2
Kukui
Laksmi 1
Lastri
Lematang
104.21747
106.20944
106.53222
106.46422
103.94372
103.95265
106.60472
108.91192
106.24964
106.65496
106.69244
106.96750
104.34408
103.22844
103.40250
104.09666
106.22417
103.31509
106.22828
106.72304
106.48694
106.48503
106.48960
106.48444
106.49262
106.49006
107.77151
102.52028
106.53783
104.15206
104.15374
104.15719
102.50778
104.18279
106.19986
107.42022
106.16667
106.21611
107.42154
103.53472
106.19351
106.40621
104.26694
-3.55180
-5.63111
-4.82278
-4.80966
-3.22833
-3.21768
-4.89167
-5.44367
-5.19639
-4.58061
-4.53646
-4.65903
-3.28472
-1.96286
-4.92972
-2.74376
-5.61639
-2.23609
-5.44481
-4.91857
-5.10833
-5.08994
-5.12065
-5.10028
-5.10153
-5.07514
-6.43745
-2.23319
-4.93254
-2.72894
-2.72518
-2.72737
-1.76667
-3.62082
-5.51583
-6.03828
-5.19250
-2.16500
-6.25681
-2.62167
-4.86978
-5.27046
-3.20833
89
-173
54
-74
108.14
145
-65
-163
-86
0
-71
-65
25
126
-33
40
-162
202
-121
-70
-69
67
-74
-70
-70
-70
134
232
-74
8
47
49
47.5
147
59
-12
-79
-82
32
94
-75
-75
25
6226
4099
6578
5613
5703
6232
5517
2635
3814
3699
3874
4310
5005
2353
2558
5095
5232
2500
4370
7504
11927
6497
6634
6389
6440
6500
8395.7
4435
5719
3551
3500
3435
5249
7853
2912
9269
4187
5217
7911
6307
4479
8889
5973
72
Lematang south
LES1
Lestari 1
Lestari 3
Linggau
Lisa 1
Lita 1
Lita 2
Loyak
Lupak
Mambang sebasa
Marwati
Maya
MB 4/ RDH 2
Mela 3
Melati
Mendarai
Menggala selatan 1
Menggala selatan 6
Merabu 3
Meruap 6
Mila 1
Mila 2
Muria
Murni
Namai
Nani
Nau 1
Nora 1
Nora 2
Nora A2
Nora South 1
Nora South 2
North Kluang 41
Notal
Nurbani 3
Onny
Padang Belawan
Pandan
Pasircatang
Peninjauan
Petar
Pilangsari
104.27875
107.55020
106.18269
106.16922
102.95065
106.52631
106.21742
106.21727
104.13139
103.92667
103.24803
106.27523
106.26361
107.30275
106.15062
104.14457
103.91451
105.21025
105.21025
104.97253
102.76635
106.45222
106.45591
107.94856
106.14806
103.21906
106.45463
103.51333
106.31472
106.32167
106.31528
106.31722
106.31489
103.88778
103.76945
106.07565
106.45083
103.98670
104.19845
108.13117
102.68988
104.28095
108.23383
-3.23219
-5.96962
-5.66942
-5.68974
-3.09448
-4.90650
-5.48567
-5.48568
-3.22250
-0.97306
-3.02486
-5.01024
-5.19194
-5.97212
-5.28716
-3.97863
-3.21321
-4.52984
-4.52984
-3.91278
-2.29011
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-5.10686
-5.60972
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-2.24322
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-3.45639
-5.50222
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30
-82
-215
-198
161
-70
-120
-120
47
-7
106
-99
111
5
-70
262
69
44.65
45
488
223
56
-72
82
32
198
-74
296
56
58
67
-120
-114
130.56
132
-66
-83
96
39
125
255
10
86
5987
3810
2314
3182
8672
5894
5432
4743
6247
4715
5926
6406
7017
4962
4530
5462
5887
2818.24
2818.24
6665
3638
11176
10346
4218
3357
3984
10825
5469
4884
3412
3530
3743
3253
3071
5915
2177
2404
5084
8115
7421
4019
4731
7131
73
Prabumenang 5
PSI AA1
PSI AA3
PSI AA5
PSI AA6
PSI AA7
PSI AAA1
PSI AB 1ST
PSI AR1
PSI AT1
PSI AU1
PSI AU2
PSI DN1
PSI E15
PSI ESP1
PSI EST1
PSI EW1
PSI EWZ1
PSI FQ1
PSI FQW 1ST
PSI FR1
PSI FSW1
PSI FSW2
PSI FSZ1
PSI FT1
PSI FT4
PSI FTE1
PSI FTX1
PSI FV1
PSI FWN1
PSI FX1
PSI G2
PSI G3
PSI GG3
PSI GGG1
PSI GP1
PSI GQE1
PSI GQS2
PSI HH1
PSI HH2
PSI K3
PSI KK2
PSI LL1
108.23383
106.55306
106.54333
106.55056
106.54758
106.53471
106.70667
106.52773
106.53833
106.50325
106.52855
106.51639
108.05569
107.99577
107.94799
107.94817
107.82854
107.87223
108.03351
107.97934
108.20058
108.05804
108.05355
108.07935
108.14306
108.14917
108.21756
108.19950
108.16250
108.17728
108.25108
107.25898
107.27866
108.63556
107.38308
107.40411
107.31926
107.26330
107.85972
107.87269
107.66619
107.54488
107.40472
-6.62264
-5.22333
-5.17389
-5.20889
-5.24606
-5.25714
-5.20722
-5.29698
-5.14267
-5.07451
-5.11952
-5.11272
-5.71645
-6.04430
-6.08048
-6.06228
-5.91457
-5.86786
-6.21024
-6.21346
-6.08146
-6.24061
-6.25976
-6.24402
-5.89069
-5.92356
-5.91468
-5.91060
-6.20194
-5.77010
-6.12914
-5.49061
-5.47362
-6.46222
-5.47428
-5.59675
-5.68466
-5.70803
-6.16583
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-6.04203
-6.10914
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247
-70
-63
-68
-70
-70
54
-79
-70
-69
-70
-68
70
-117
40
-104
-139
-143
-51
73
40
-44
-35
-123
-149
-145
-146
-147
40
-158
65
-150
-147
54
64
-152
67
75
50
54
65
-35
57
5399
4309
5150
4562
4352
7069
5697
7183
6319
8517
7180
7320
4605
6680
7710
6370
5859
6232
6936
10300
5110
7714
7946
6975
4489
4696
4023
3705
7764
3927
5415
3297
3291
4952
4307
6863
4928
4270
7530
7697
6605
8220
5673
74
PSI LLQ
PSI LLX
PSI MKN
PSI ML
PSI MO
PSI MP
PSI MV
PSI NF
PSI NG
PSI OE10
PSI OE8
PSI OM
PSI ON
PSI OU 1
PSI OU 3
PSI OV
PSI OWA
PSI OX1
PSI OX2
PSI OY
PSI OZ
PSI P10
PSI P11
PSI P2
PSI P6
PSI P7
PSI P9
PSI PM
PSI PN
PSI PZ
PSI SB
PSI SC
PSI SD
PSI TY
PSI U5
PSI UQ
PSI W
PSI WG
PSI X3
PSI XM 1
PSI XM3
PSI XW
PSI XW 3
107.42392
107.49961
107.35075
107.18242
107.09279
107.03658
107.23118
106.54874
106.56734
108.56868
108.54714
108.53549
108.48374
108.43292
108.42435
108.45643
108.39725
108.42708
108.43536
108.44500
108.35878
107.02222
107.05764
107.01508
107.04126
107.02897
107.04278
107.03936
107.10708
106.85606
107.60385
107.58641
107.63481
107.45469
107.88145
107.92142
107.69472
108.63931
108.66694
108.56227
108.57594
108.59977
108.60733
-5.77206
-5.77011
-5.92222
-5.94222
-5.85525
-5.83467
-5.88694
-5.01497
-5.02721
-6.43633
-6.45049
-6.30755
-6.28740
-6.21294
-6.20846
-6.11417
-6.24956
-6.25403
-6.22917
-6.16958
-6.16169
-5.83064
-5.78773
-5.81917
-5.76667
-5.79081
-5.80736
-5.63678
-5.50297
-5.51027
-5.81017
-5.73313
-5.70311
-5.62772
-6.05996
-6.12264
-5.40444
-6.55593
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-6.33668
-6.33384
40
-137
75
-32
-94
61
58
-73
-68
71
-17
-70
-67
-143
-104
-133
-50
-75
-95
-121
-111
-102
67
34
65
-106
-110
40
-151
-137
-144
78
78
-156
65
40
87
84
-152
-89
71
-66
-72
6581
9334
7725
4632
4327
3264
3970
6106
5700
6509
7288
5228
5208
5067
5300
4076
6500
4939
4566
4310
5040
3290
3483
3452
3585
3361
3414
3756
3448
3005
8472
9982
10097
7373
7616
7637
3176
5473
4541
5195
5276
4100
4050
75
PSI Z
PSI ZUD
PSI ZZZ
Putih
Quinta
Rama
Riamar
Rima
Rimbabat 2
Rimbo
Rini
Rinjani
Rumbi
Sambidoyong
Saung naga
Selangit 1
Selatan 2
Semeru
Semi
Serian
Siarak
Sibayak
Sita
Soputan
Sri
Sukaraja 1
Sukaraja 2
Sukaraja 3
Sukaraja 7
Susana
Tabuan 1
Tabuan Selatan
Talang Gendum
Talau
Tambun
Tampan
Tanjung kurung 1
Tapir
Tasim
Tebing Tinggi
Tiara
Tiga Duri
Widuri 1
106.67778
106.55944
106.53644
103.99244
106.66500
106.28894
106.40671
109.14111
104.13146
104.33773
106.27030
108.40158
104.13080
108.38254
103.18242
103.01869
106.18583
108.38819
102.99389
102.51667
103.72861
108.23945
106.42431
108.46515
106.03450
104.03720
104.03068
104.03442
104.01965
106.66536
104.21778
104.21650
103.94734
102.25496
107.02883
104.22772
104.12435
103.81698
104.05922
103.09806
106.19331
104.18222
106.62632
-5.36528
-5.35656
-5.32156
-3.98867
-4.91639
-5.44736
-4.70944
-5.29361
-2.13146
-2.93423
-5.50023
-5.60849
-2.76473
-6.37154
-3.61471
-3.78901
-5.55500
-6.01746
-3.38000
-1.47917
-2.74250
-5.84501
-4.99908
-5.64190
-5.16872
-3.19703
-3.19083
-3.19322
-3.18131
-4.59440
-2.71417
-2.74695
-3.28864
-0.18026
-6.13331
-3.12444
-3.12231
-3.51109
-3.81941
-1.01389
-5.07736
-2.47889
-4.66436
54
-95
63
33
60
-123
0
32
10
68
-114
60
30
5
269
144
120
82
275
151
73
60
-77
82
47
18
15
13
17
-70
10
6
162
36
13
20
16
117
216.5
79
-63
7
-70
4266
2953
3295
6762
6347
4022
7245
3269
3262
1972
8917
3627
2918
9808
3701
6046
3277
3958
2942
4111
8495
4279
10587
5260
2692
7345
6856
6798
6960
4059
4067
2230
6760
6299
2340
4648
5527
6363
6425
5361
4599
4732
3750
76
Yasrid 1
Yati 1A
Zelda 1
Zelda 4
Zelda 7
106.91816
106.14278
106.37361
106.35536
106.37722
-4.81944
-5.47861
-3.18750
-5.05900
-5.12000
-78
-99
-70
-72
-77
10263
4332
8342
8182
8954
77
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