STATUS OF THESIS ASSESSMENT OF A SYNRIFT PLAY IN SOUTH DENT GRABEN (OFFSHORE EAST SABAH) I, HARMINZAR BINTI MANSOR hereby allow my thesis to be placed at the Information Resource Center (IRC) of Universiti Teknologi Petronas (UTP) with the following conditions: I. The thesis becomes the property of UTP 2. The IRC ofUTP may make copies of the thesis for academic purposes only 3. The thesis is classified as CJ 0 Confidential Non confidential Reason: As instructed by Petroleum Management Unit (PMU), Petronas. Endorsed by PRAM,PMU PRAM,PMU Level 22, Tower 2, Level 22, Tower 2, Petronas Twin Towers, Petronas Twin Towers, KLCC KLCC Date: 22/1/08 11
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STATUS OF THESIS
ASSESSMENT OF A SYNRIFT PLAY IN SOUTH DENT GRABEN
(OFFSHORE EAST SABAH)
I, HARMINZAR BINTI MANSOR hereby allow my thesis to be placed at the
Information Resource Center (IRC) of Universiti Teknologi Petronas (UTP) with the
following conditions:
I. The thesis becomes the property of UTP
2. The IRC ofUTP may make copies of the thesis for academic purposes only
3. The thesis is classified as
CJ 0
Confidential
Non confidential
Reason:
As instructed by Petroleum Management Unit (PMU), Petronas.
Endorsed by
PRAM,PMU PRAM,PMU
Level 22, Tower 2, Level 22, Tower 2,
Petronas Twin Towers, Petronas Twin Towers,
KLCC KLCC
Date: 22/1/08
11
UNIVERSITI TEKNOLOGI PETRONAS
Approval by Supervisor
The undersigned certify that they have read, and recommend to The Postgraduate Studies
Programme for acceptance, a thesis entitled "Assessment of a synrift play in South
Dent Graben (offshore East Sabah)" submitted by Harminzar Mansor for the
fulfillment of the requirements for the degree of Master of Science in Petroleum
Signature:
Main supervisor: Dr Arthur Van Vliet
Date: zz/•jo~
Geoscience.
Ill
UNIVERSITI TEKNOLOGI PETRONAS
ASSESSMENT OF A SYNRIFT PLAY IN SOUTH DENT GRABEN (OFFSHORE
EASTSABAH)
By
HARMINZAR MANSOR
A THESIS
SUBMITTED TO THE POSTGRADUATE STUDIES PROGRAMME
AS A REQUIREMENT FOR THE
DEGREE OF MASTER OF SCIENCE IN PETROLEUM GEOSCIENCE
BANDAR SERI ISKANDAR,
PERAK
JANUARY, 2008
IV
DECLARATION
I hereby declare that the thesis is based on my original work except for quotations and
citations which have been duly acknowledged. I also declare that it has not been
previously or concurrently submitted for any other degree at UTP or other institutions.
Signature :~ Name : Harrninzar Mansor
Date
v
ASSESSMENT OF A SYNRIFT PLAY IN SOUTH DENT GRABEN (OFFSHORE
EASTSABAH)
ABSTRACT
South Dent Graben is located offshore of East Sa bah at the south part of the Sandakan
Sub basin. This basin is a very lightly explored area. There is only one exploration well
drilled here. The stratigraphy of this basin mainly divided into two parts: synrift
sediments and post rift sediments. They are separated by the breakup unconformity that
represents the Middle Miocene Unconformity (MMU). Post rift sediment consists of the
Sebahat Formation, the Ganduman Formation and the Togopi Formation. The
interpretations and petroleum play analysis of the post rift sediments have been done in
2005. Basically this project is a continuation from the 2005 project but focused more on
the synrift sediments. Synrift sediments are represented by Segama Group (Libung and
Tungku Formation), deposited during Early- Middle Miocene. Five horizons have been
interpreted: Top Basement, Base Purple, Base Brown, Base Green and Middle Miocene
Unconformity. From the seismic interpretation and mapping that has been done, no
economic size structural trap or stratigraphic play appears in the synrift sediments. Synrift
sediments only present in a small part of the basin and later overlain by extensive postrift
sediments through out the whole basin. Even though the north part of the basin has
hydrocarbon occurrences in the synrift sediments (Tanjong Formation/Segama Group),
the reservoir appears more equivalent to the Tanjong Formation. High proportion of
volcaniclastic sediments and conglomerates is the reason that the Segama Group is not a
good reservoir. Besides that, a calculation from the Vrms also shows very high interval
velocity ranging from 3000ms'1 to more than 4000ms'1, suggesting that the sediment is
compacted, has a low porosity and may not be a good reservoir.
VI
TABLE OF CONTENTS
STATUS OF THESIS
APPROVAL PAGE
TITLE PAGE
DECLARATION
ABSTRACT
TABLE OF CONTENTS
LIST OF TABLE
LIST OF FIGURES
CHAPTER ONE: INTRODUCTION
I. I OBJECTIVE
1.2 LOCATION AREA
1.3 PROJECT DATABASE
l.3.I SEISMIC
1.3.2 WELL
I.4 PROBLEMS ENCOUNTERED
CHAPTER TWO: LITERATURE REVIEW
2.I TECTONIC EVOLUTION OF SABAH
2.2 STRATIGRAPHY OF SABAH
2.3 VOLCANIC ACTIVITY IN SABAH
2.4 SANDAKAN SUB BASIN
2.4.I DENT PENINSULA STRATIGRAPHY (ONSHORE)
2.4.2 STRATIGRAPHY
2.4.3 SOURCE ROCK POTENTIAL
2.4.4 RESERVOIR
2.4.5 MATURITY
CHAPTER THREE: METHODOLOGY
3.I DATA COLLECTING
3.2 SEISMIC INTERPRETATION
3.3 MAPPING
VII
II
Ill
IV
v
VI
VII
IX
X
2
2
3
4
5
9
IO
IO
I2
I3
I4
I5
I5
I6
I6
22
3.4 VELOCITY CALCULATION
CHAPTER FOUR: RESULT
4.1 SEISMIC INTERPRETATION
4.2 MAPPING
4.3 VELOCITY CALCULATION
CHAPTER FIVE: CONCLUSION AND RECOMMENDATION
REFERENCES
APPENDIX A: Velocity calculation results
VIII
22
25
42
48
51
LIST OF TABLE
Table
4.1 Color code that have been used to interpret horizon in this project 25
IX
Figure
1.1
1.2
1.3
2.1
2.2
LIST OF FIGURES
Location area of this project
Basemap of the seismic lines in the SB306 block
Summary of Sebahat-1 well
NW -SE cross section across Sa bah during Cretaceous-Eocene
NW-SE cross section across Sabah during Oligocene-Early Miocene
2.3 NW -SE cross section across Sa bah during Early Miocene
Middle Miocene
2.4
2.5
2.6
2.7
NW -SE cross section across Sa bah during Late Miocene-Pliocene
The structural elements in Sandakan Sub Basin
Lithostratigraphy map of South Dent
Lithostratigraphy ofSandakan Sub Basin
3.1 SB30604-04 seismic line show the erosional truncation as
the indicator to Base Green
3.2
3.3
3.4
Other erosional truncation as indicators of Base Green
Onlap end to basement
On lap seismic reflections as indicator of Base Purple
3.5 Graph of relative error versus interval thickness in ms (using the
Dix formula)
4.1 Interpreted SB30604-04 seismic line
4.2 Interpreted SB30604-06 seismic line
4.3 Interpreted SB30604-08 seismic line
4.4 Interpreted SB30604-1 0 seismic line
4.5 Interpreted SB30604-12 seismic line
4.6 Interpreted SB30604-14 seismic line
4.7 Interpreted SB30604-05 seismic line
4.8 Interpreted SB30604- I I seismic line
4.9 Interpreted SB30604-19 seismic line
4.10 Interpreted SB30604-23 seismic line
4.11 Interpreted SB30604-27 seismic line
4.12 Interpreted SB30604-31 seismic line
4.13 Interpreted SB30604-39 seismic line
X
2
3
4
6
7
8
9
II
12
14
18
19
20
21
23
26
27
28
29
30
31
32
33
34
35
36
37
38
4.14 Interpreted SB30604-43 seismic line 39
4.15 Interpreted SB30604-45 seismic line 40
4.16 Interpreted SB30604-53 seismic line 41
4.17 Middle Miocene Unconformity (MMU) time structure map 43
4.18 Base Green time structure map 44
4.19 Base Brown time structure map 45
4.20 Base Purple time structure map 46
4.21 Basement time structure map 47
4.22 Summary of the velocity results on SB30604-04 49
4.23 Summary of the velocity results on SB30604-06 50
XI
CHAPTER I
INTRODUCTION
1.1 OBJECTIVE
The main objective of this project is to assess synrift sediments and prospectivity in
the South Dent Graben, Sabah, Malaysia.
1.2 LOCATION AREA
The south Dent Graben is located offshore of the East part of Sabah. It is under
SB306 acreage. This area is virtually unexplored. Total area of this block is
8184km2 The block is currently open block area. The basin in this area is known as
Sandakan Sub Basin. This project only focuses on the south part of the Sandakan Sub
Basin.
Sulu Se.
S'OO' 58332
Figure 1.1 Location area of this project
1.3 PROJECT DATABASE
1.3.1 SEISMIC
Two seismic surveys have been done in SB306:
1. ESB99 Series - This survey has been shot by Petronas in 1999. It comprises
1500 line km
2. SB30604 Series- Shot by Petronas in 2004 and comprises 1471 line km.
For this project only SB30604 have been used in the interpretation to avoid misties
between the two vintages.
2
3
Figure 1.2 Basemap of the seismic lines in the SB306 block
1.3.2 WELL
There is only one exploration well in the SB306 acreage which is Sebahat-1. The well
was drilled in 1973 by Sabah Teiseki Oil. Total depth of this well is 3700m TVDSS.
Sebahat-1 is a dry well and only has minor gas shows from the cuttings.
Haile, N. S. and Wong, N. P. Y., 1965. The geology and mineral resources of the Dent Peninsula, Sabah. Geological Survey, Borneo Region, Malaysia, Memoir 16.
Hutchinson, C. S., 1989. Geological evolution of South-East Asia. Clarendon Press, Oxford, 368.
Lim, P.S., 1985. Geological map of Sabah (3'd Edition), Geological Survey of Malaysia.
Murphy Oil Corporation, 2000. Prelimanary assessment of hydrocarbon prospectivity in blocks SB305 & SB306, Offshore Sabah, Malaysia.
Petronas, 1999. The petroleum geology and resources of Malaysia. PETRONAS.
Petronas, 2006. Seismic Sequence Stratigraphy & Petroleum Play Analysis of Southern Dent Peninsular, Block SB306 Offshore Sabah, Malaysia.
Tongkul, F., 1991a. Tectonic evolution of Sabah, Malaysia. In: Nichols, G. and Hall, R. (eds.) Proceeding of Orogenesis in Action Conference London, 1990. Journal of Southeast Asian Earth Sciences, 6, 395-405.
Tongkul, F., 1997. Polyphase development in the Telupid area, Sabah, Malaysia. In: Geosea 1995 Proceedings, Journal of Asian Earth Sciences, 15, 175-184.
Xia, K. Y. and Zhou, D., 1993. The geophysical characteristics and evolution of northern and southern margins of the South China Sea. Bulletin of the Geological Society of Malaysia, 33,223-240.