1. 2.1 DIMENSIONAL CROSS IMAGING
From the surface map, the depth cross section was drawn to visualize the contour line in two dimensional views.
The horizontal and vertical cross sections -plotted using Microsoft Excel spreadsheet and point reader based on pixel, ImageJ.
On the x-axis: width (horizontal and vertical) while the y-axis: thickness of each zone

2. TWO METHODS OF DEPTH CONVERSION OF TIME MAPS
Manual calculation from the graph
- not give accurate result due to small scale of the maps (1:233), and since the actual reservoir layers are only approximately 20-50m in thickness, which is represented in a minor 1mm in the A4 paper can easily lead to stacking of layers
Moving to the result of Image_J software
- The results of the plots are shown in Spreadsheet horizontal cross section for Gelama Merah 1 and ST-1

3. SPREADSHEET HORIZONTAL CROSS SECTION FOR GELAMA MERAH 1 AND ST-1

4. 2.2 STRATIGRAPHY AND RESERVOIR GEOLOGY
the oil accumulation : zone U9.0 and U9.1.
The thin oil layers : above the GOC is at zone U3.2, U5.0 and U9.0 above the GOC level
3 different depositional time frame. 1. zone U9.0 until U10.0 was firstly deposited and sedimented. 2.new sedimentation of zone U5.0-U8.0 >uplifted > zones pinched > possible erosion > uncomformity layer when the new sedimentation of U3.2 and U4.0 occurs. 3.tectonic might have caused another possible uplift that gives the Gelama Merah the current anticlinal shape it has now.
marine hiatal events / surface wave, cross stratification and burrows.
all sands packages as very fine to fine grained, poor consolidated to unconsolidated sand
Two lithofacies are interpreted ,cross-bedded sandstones, planar bedded sandstone, laminated sandstone, massive sandstone, fosiliferous sandstone, claystone and dolomite (from the drilling report for rock lithologies).
Reservoirs are stratified, with extensive shale barriers acting as both top and bottom seals.
The hydrocarbon bearing reservoirs in Gelama Merah area are represented by topset 2D cross section and also quick-look method from the logs proven by Microsoft Excel Spreadsheet calculations.
It is interpreted as a prograding event, shallow marine sand and with continuous shale package. Oil with thick gas cap was discovered in Unit 4.0, Unit 5.0, Unit 6.0, Unit 7.0, Unit 8.0, Unit 9.0, Unit 9.1, and Unit 9.2. Gelama Merah-1 discovered a total of 158 m of net gas sand and 30 m of net oil sand from Unit 4.0 to Unit 9.1. Gelama Merah-1 ST-1 discovered a total of 53 m of net gas sand and 26 m of net oil sand in Unit 9.0 and Unit 9.2. (These values are shown in the later section of Petrophysics chapter. Proven Gas Oil Contact (GOC) was established at 1468 m TVDSS for the sand units.

5. 2.3 REGIONAL SETTING
GM is located in the offshore Sabah basin, in the West Labuan-Paisley Syncline: characterized by a major North-South growth Morris Fault .The regional wrench fault was interpreted by Rice-Oxely (1991) and Tan and Lamy (1990
Gelama Merah is deposited in the later part of Middle Miocene sands and has the depositional environment of prograding delta and coastal complex.
4 major prograding sand packages were recognized within the targeted reservoir levels and they are characterized by interbedded sand shale, coarsening upwards.
A small erosion occurrence can be clearly seen and it is assumed to be the result of the movement of Morris Fault followed by landslide near the up-thrown block.
A thin continuous layer of shaly to silty sand was then filled the eroded area.
the structure is to be exposed to the northwesterly striking channels, dissecting delta top thus forming the unconformity.
This is proven and supported by the wells correlation of Gelama Merah field. The mentioned unconformity represents a major movement of the Morris Fault and it is also found that the unconformity pointed out a drastic change in the depositional environment, from deeper in the underlying interval (coastal) to shallower coastal plain.

6. 2.4 EXPLORATION OPPURTUNITY
Past explorations activities in the western and northern Sabah have been traditionally focused on the inboard areas of the continental shelf. The areas have been explored for the past 100 years, where first oil seeps were reported from the Kudat Peninsulas. The first ever offshore well developed in Sabah Basin was the Hankin-1, which was drilled SHELL Sabah/Pecten in 1958.
The oil and gas production from Sabah account for approximately 15% and 5% dated in 2005, of the total production in Malaysia, respectively. There are currently 7 producing fields in the Sabah Basin (Ketam has already ceased production) and, except for Kinabalu, all the fields were discovered before 1980.
The Gelama Merah field is specifically located in the sub-block 6S-18 of Block SB 301. Recent exploration targets are clastic and carbonate reservoirs of Miocene and Pliocene age. There are currently seven offshore blocks under exploration PSC or have exploration commitments. Most of these blocks are located in the west Sabah area and are available under the Revenue over Cost (R/C) PSC terms.

7. 2.5 THE PETROLEUM SYSTEM Maturation and Migration
as of the Miocene-Pliocene deltaic accumulation at a convergent margin. Migration along the faults is a major method of migration.
Source Rocks
The hydrocarbons are very similar in composition,originated from source rock which are rich in terrigenious organic matter
Reservoir Rocks
consist of intebedded sandstone with non-reservoir formation of thin shales.
Traps and Seals
anticlinal features, stratigraphic traps unrelated to anticlinal features as the unconformity trapping mechanism that traps the hydrocarbons in our units of interest.

8. 2.6 DEPOSITIONAL ENVIRONMENT
The depositional is dominated by the deltaic environment. Based on core data, a less considerable variation in grain size and sorting was observed within the sand body contained in the units of interest.
From the Gelama-2 ST1 core data, zone beyond the unconformity is shale interlaminated scarcely with sand. Shale in the Gelama Merah field reservoir is hard to fairly hard, well compacted, finely fissile, micromicaceious, smoothly sloppy.
Cross bedded layers of sand and conglomerate with shaly sand. The regional tilting of the basin north west wards and the basin ward migration of the hinge lines that separate unconformities from there correlative conformities\

9. 2.7 DIMENSIONAL STATIC MODEL (PETREL 08)
General Description :
-implies the 3-D structure of the reservoir zones based surface contoured from surface maps +lithologies correlated from log readings+ facies based on depositional environment.
-using Schlumberger’s PETREL software. Ten surface maps were digitized and stacked on the depths to produce a geocellular reservoir model.
Model Parameters:
- They are defined for the same value of X-axis value from to meter East, and for Y-axis value from to meter North. This approximates to a perimeter of investigation at 6200 meter from west to east and 3700 meter from north to south
Top Structure for Unit 3.2

10. CONT’ : DIMENSIONAL STATIC MODEL (PETREL 08)
Top Structure Development :
The BMP image file input into PETREL- >coordinates in the 3 dimension are set for X,Y,and Z axi -> by dotting the lines in the surface maps to make poligon 3D -> transferring the contours to the desired depth.
Creating new wells:
The identical wells for explorations were created by “Input new well” option from the Input window. The well deviation data were previously compiled from drilling reports and imported to PETREL for both the sidetrack and vertical well.

11. CONT’ : DIMENSIONAL STATIC MODEL (PETREL 08)
5. Stratigraphic Modeling :
The U3.2 to U8.0 is identified from well GM-1 but not in GM-ST1. This is also shown in the 2D cross image from Excel as the zones are truncated. Therefore the zones are not correlated to the neighbor well.
Both wells logs show the existence of U9.0 to U9.3. For this case, the Gamma Ray log is used. However, if we already obtained the depth of each zones from log interpretation, any log (even Calipher or Resistivity) can be used as a correlation log. This correlation will appear in all logs.

12. CONT’ : DIMENSIONAL STATIC MODEL (PETREL 08)
6.Structural Modeling
List of horizon name, horizon type and input for making zones

13. CONT’ : DIMENSIONAL STATIC MODEL (PETREL 08)
Cross sectional view of the GM-1 and GM-ST1 exploration well on the 10 top surface structures stacked.
Correlating the layers with the facies from log

14. CONT’ : DIMENSIONAL STATIC MODEL (PETREL 08)
7. Properties Modeling:
-final section towards the static model in PETREL. The well logs were scaled up for the properties of neutron-density porosity, facies, water saturation and effective porosity: to allow PETREL to virtually categorize the values of each property in every 5mins for the volumetric estimation in the next section.
-The facies modeling option were then selected.
-The nugget of the variogram is set to be E-W direction based on the depositional environment which was defined in the earlier section with the angle of azimuth 90˚. The minor direction is set to 500, and major direction 1000, with the vertical value of 4..

15. 2.8 HYDROCARBON VOLUMETRIC ASSESSMENT SIMULATION
Case
Bulk volume [*10^3 m3]
Net volume[*10^3 m3]
GIIP [*10^3 sm3]
STOIIP (in oil)[*10^3 sm3]
Group6
161475
109845
16404
12215
Zones
U3.2
17640
10806
110 11
U3.2 base
2633
1781 22
U4.0
1364
919
207
U4.0 base
228
148 33
U5.0
702
566
U5.0 base
1265
752
197
U6.0
1668
956 44 18
U6.0 base
924
658 30 4
U7.0
5412
3715
338
U7.0base
773
441 40
U8.0
4442
3004
4651
U8.0base
847
428
663
U9.0
19419
13538
9557 34
U9.0base
4039
2298
U9.1
11376
7456
6503
U9.1base
6235
4317
232
U9.2
50843
36558
U9.3
25315
16672 1
U9.3base
6351
4833
HC intervals : includes oil interval only
Upper contact : Gas oil contact
Lower contact : Oil water contact
Porostiy : PHIE (effective) and Net to Gross
Recovery for STOIIP : 1.00 ; Bo (FVF): [rm3/sm3]
Recovery for GIIP : 1.00; Bg = 0.01 cuft/scf , stb/scf
PHIE = Total Porosity * (1-Vshale)
STOIIP in sm3: *10^3 sm3
Conversion Factor from sm3 to bbl, 1sm3 = bbl
STOIIP in bbl : 76.83MMStb
GIIP in scf : MMMScf

16. 2.9 RISK ANALYSIS AND UNCERTAINTIES
sand structure-sand is poor consolidated to unconsolidated, with very fined to fine grained : problem during
The varieties of lithofacies, increase the reservoir heterogeneity.
Core analysis did not provide sufficient information on the sand distribution throughout the Gelama Merah area.
As for the 3D static model, without information from the seismic data, it lacks information to built a complete and accurate fault model.
Available logs are only from Gelama Merah field. Therefore, in the well tops and horizons setting, the top layer U3.2 (facing towards the east) will be slightly thicker as it is virtually being pulled by the welltops since there are no correlations of wells available towards the east of well GM-1.