2. 2-D SEISMIC DATA INTERPRETATION AND
VOLUMETRIC ANALYSIS OF DHULIAN AREA
UPPER INDUS BASIN, PAKISTAN.
FASIH AKHTAR
WASEEM ABBAS
HASNAIN ZAHOOR AWAN
SUPERVISOR: M. FAHAD MAHMOOD
EXTERNAL SUPERVISOR: Mr. SARMAD HASSAN SHARIF
2010-2014

3. OUTLINE OF PRESENTATION
 Introduction Of the Area
 Objectives
 Methodology Adopted
 Overview of Potwar Sub Basin
 Petroleum System
 Seismic Interpretation
 Petrophysical Analysis
 Conclusions

4. OBJECTIVES
 To carry out the seismic data interpretation and mapping of the area
in order to understand the subsurface structural geometry of
Dhulian anticline.
 Preparation of Time and Depth Sections
 Petrophysical Analysis of Dhulian-43 well to understand the
reservoir potential of the structure.
 Volumetric Analysis of the area to calculate remaining potential of
the structure.

5. AREA OF INVESTIGATION
 The Study area of Dhulian is located in the Eastern
Potwar basin.
 The Dhulian Area is bounded by Latitude 33 12'41“N
and Longitude 72 12'00“E.
 The Nearest city to the Dhulian study area is Pindi Gheb.
 Oil was also discovered for the first time in Indo-
Pakistan from Paleocene reservoirs, during further
appraisal of Dhulian structure.

6. LOCATION MAP

7.  A total of 49 wells were drilled in Dhulian oil field
 Three wells have been drilled by Attock Oil Company
(A.O.C.)
 46 wells have been drilled by Pakistan Oilfields Limited
(P.O.L)
 Seven wells did not reach objective reservoirs and three wells
could not be put on production due to various technical
reasons.

8. ACCESSIBILITY MAP
Courtesy: P.O.L. Geologic Bulletin 2004
Dhulian Oil
Field

9. Alluvium, Sandstone,
siltstone etc
Siwaliks
Group
Thrust
Fault
Anticli
ne
Syncline
Rawalpindi
Group
Oil fields
N
Dhulian
Oil Field
Kazmi and Abbasi, 2008
GEOLOGICAL MAP

10. PETROLEUM PLAY
PLAY
ELEMENTS
FORMATONS AGE
TRAP Structural Trap
SEAL Murree Formation
Nammal Formation
Miocene
Paleocene
RESERVOIR Chorgali Formation
Sakesar Limestone
Lockhart Formation
Wargal Formation
Eocene
Eocene
Paleocene
Permian
SOURCE Patala Formation Paleocene

11. TECTONIC MAP OF POTWAR SUB-BASIN
(Kadri, 1995)

12. GENERAL STRATIGRAPHY OF DHULIAN AREA
(Kazmi and Jan, 1997)

13. BOREHOLE STRATIGRAPHY
Total Depth 3788m , A.O.C, 22-03-1963
Formations Depth (m)
CHINJI 0
RAWALPINDI GROUP 886
MAMI KHEL 2498
CHORGALI 2524
SAKESAR 2590
NAMMAL 2683
PATALA 2741
LOCKHART 2813
HANGU 2869
MIANWALI 2886
CHIDDRU 2932
WARGAL 2987
AMB 3136
SARDHAI 3214
WARCHA 3291
DANDOT 3444
TOBRA 3508
SALT RANGE 3632

14. STRUCTURE
 Dhulian fold is flanked by the Soan Syncline to the south and by the
tight Pindi Gheb syncline to the north
 The Dhulian structure was originally thought to be a conventional
anticline with a fold axis trending northeast southwest.
 Based on this new seismic evidence, Dhulian structure was proved to
be a thrust-bounded salt-cored anticline,
 It is cut across by a major wrench fault that splits Dhulian into two
major fault blocks
 As a result, the Dhulian structure may be compartmentalized.

15. 3-D VIEW OF DHULIAN STRUCTURE
Courtesy: P.O.L Geologic Bulletin 2004

16. SEISMIC DATA
INTERPRETATION

17. Depth Contour Maps
Time to Depth Conversion
Velocity Analysis
Time Contour Maps
Time Picking
Marking of Faults
Marking of Prominent Reflectors
T-D Chart
METHODOLOGY

18. DATA USED
Line
Name
PDK-102 PDK-103 PDK-104 PDK-113
WELLDATA
Line Dip line Dip line Dip line Strike line
DHULIAN-43
(Gamma ray
log, Neutron
Log and
Resistivity logs)
Line
Direction
North-South North-South North-South East-West
SP Range 108-188 108-218 108-298 108-340
Date
Recorded
1981 1981 1981 1981

19. BASE MAP

20. T-D CHART
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
3250
3500
3750
4000
0 200 400 600 800 1000 1200 1400 1600 1800 2000
T-D Graph
T-D Graph
Lockhart Formation
Wargal Formation
Chorgali Formation
Depth
Time

21. SEISMIC SEQUENCES & REFLECTION
FEATURES
 In the study area four sets of seismic sequence are encountered on the basis of
seismic reflection features.
 Sequence 1: Continuous and Dark reflectors at the bottom of Seismic Section
stands for the basement of Pre-Cambrian age.
 Sequence 2: Strong to medium continuous reflections, great change in
thickness, it is Infra Cambrian aged Salt Ranges Formation composed of salt
and evaporates. A great decollement plane is development.
 Sequence 3: Parallel and continuous reflections high amplitude and
frequency. It stands for Paleocene –Eocene ages formation. The traditional
reservoirs in Potwar were developed in this sequence.
 Sequence 4: Parallel and weak to continuous reflections. It stands for
Miocene aged Mollasse architecture.

22. REFLECTORS MARKING
In total three horizons have been mapped throughout the study
1. Chorgali Formation (Eocene)
2. Lockhart Formation (Paleocene)
3. Wargal Formation (Permian)
 These three horizons comprise the target horizons for
hydrocarbon exploration in the study area.
 Chorgali Formation was picked as it is a very strong
reflector beneath the Kohat Formation i.e. Eocene

23.  Lockhart Formation (Paleocene) was picked in the base of
decreasing acoustic impedance from Nammal Formation
to Patala Formation and then increasing peak of Lockhart
Formation.
 Wargal Formation was picked below to Lockhart
Formation. The reflection continuity is fair to good.

24. PDK-102

25. PDK-103

26. PDK-104

27. PDK-113

28. PDK-102
Time Section

29. PDK-103
Time Section

30. PDK-104
Time Section

31. PDK-113
Time Section

32. TIME CONTOUR MAPS
 Contouring the time structure maps and finding structural traps are
one of the basic goals of Seismic data interpretation.
 In this respect three time contour maps have been prepared on three
different horizons in the whole area at the scale of 1:50, 000.
 1. Time Contour Map of Chorgali Formation (Eocene)
 2. Time Contour Map of Lockhart Formation (Paleocene)
 3. Time Contour Map of Wargal Formation (Permian)

33. TWT Map on Top Chorgali of Dhulian D & P
Lease
TIME CONTOUR MAP OF CHORGALI
FORMATION

34. TWT Map on Top Lockhart of Dhulian D & P Lease
TIME CONTOUR MAP OF LOCKHART
FORMATION

35. TWT Map on Top Wargal of Dhulian D & P Lease
TIME CONTOUR MAP OF WARGAL
FORMATION

36. DEPTH CONTOUR MAPS
 The following depth maps have been prepared at the scale of
1:50,000 with respect to mean sea level.
1. Depth Structure Map of Chorgali Formation
2. Depth Structure Map of Lockhart Formation
3. Depth Structure Map of Wargal Formation
 These maps have been prepared mainly using the drilling well tops
available on different wells in Dhulian area.

37. DEPTH CONTOUR MAP OF CHORGALI
FORMATION
C.I. 20 ft
S.R.D
400 m

38. DEPTH CONTOUR MAP OF LOCKHART
FORMATION

39. DEPTH CONTOUR MAP OF WARGAL
FORMATION

40. PETROPHYSICAL ANALYSIS
 Well Dhulian-43.
 Located on:
Lattitude 33 12'41“N
Longitude 72 12'00“E.
 Total Depth:
3788 meters
 Interpretation is done on Chorgali and Lockhart Formation.

41. WORK FLOW
Marking of
Zone of
Interest
Lithology
Identification
Volume of
Shale
Effective
Porosity
Total
Porosity
Saturation of
Water
Saturation of
Hydrocarbon
Summation

42. MARKING ZONE OF INTEREST
Formation
Starting depth
(m)
Ending depth
(m)
Total thickness
(m)
Chorgali
Fm
2494m 2560m 66m
Lockhart
Fm
2783m 2839m 56m

43. PETROPHYSICAL ANALYSIS
 Logs used
• Gamma Ray Log
• Neutron Log
• Density Log
• Resistivity Log

44. GAMMA RAY LOG
 Amount of radioactivity.
 Differentiate between shale and sand content.
 To calculate shale volume
Volume of Shale (Vsh) = GRlog – GRmax / GRmax – GRmin

45. 8200
8250
8300
8350
8400
8450
0 10 20 30 40 50 60 70
Depth Vs Shale Volume
Depth Vs Shale Volume
Depth(ft)

46. DENSITY & NEUTRON LOG
 Delineation of porous formation and their porosity.
Density Porosity = Densitymatrix – Densitylog / Densitymatrix – Densityfluid
Neutron Porosity = Value of Neutron Log
Average Porosity = (Density Porosity + Neutron Porosity) / 2
Effective Porosity = Porosityavg * (1- Vsh)

47. 8200
8250
8300
8350
8400
8450
0 5 10 15 20
Depth Vs Average Porosity
Depth Vs Average Porosity
Depth(ft)

48. 8200
8250
8300
8350
8400
8450
0 2 4 6 8 10 12 14
Depth Vs Effective Porosity
Depth Vs Effective Porosity
Depth(ft)

49. RESISTIVITY LOG
 Use for determination of resistivity of formation.

50. 8200
8250
8300
8350
8400
8450
0 5 10 15 20 25 30 35 40
Depth Vs Saturation of Water
Depth Vs Saturation of Water
Depth(ft)

51. 8200
8250
8300
8350
8400
8450
0 20 40 60 80 100 120
Depth Vs Saturation of Hydrocarbons
Depth Vs Saturation of
Hydrocarbons

52. COMPOSITE DIAGRAM
8200
8250
8300
8350
8400
8450
0 20 40 60 80 100 120
Volume of Shale
Average Porosity
Effective Porosity
Saturation of Water
Saturation of Hydrocarbons
Depth(ft)

53. Lockhart Formation

54. 9120
9140
9160
9180
9200
9220
9240
9260
9280
9300
9320
0 20 40 60 80 100 120
Depth Vs Volume of Shale
Depth Vs Volume of Shale
Depth(ft)

55. Depth(ft)
9120
9140
9160
9180
9200
9220
9240
9260
9280
9300
9320
0 5 10 15 20
Depth Vs Average Porosity
Depth Vs Average Porosity

56. 9120
9140
9160
9180
9200
9220
9240
9260
9280
9300
9320
0 2 4 6 8 10 12 14
Depth Vs Effective Porosity
Depth Vs Effective Porosity
Depth(ft)

57. 9120
9140
9160
9180
9200
9220
9240
9260
9280
9300
9320
0 10 20 30 40 50
Depth Vs Saturation Of Water
Depth Vs Saturation Of Water
Depth(ft)

58. 9120
9140
9160
9180
9200
9220
9240
9260
9280
9300
9320
0 10 20 30 40 50 60 70 80
Depth Vs Saturation of Hydrocarbons
Depth Vs Saturation of
Hydrocarbons
Depth(ft)

59. COMPOSITE DIAGRAM
9120
9140
9160
9180
9200
9220
9240
9260
9280
9300
9320
0 10 20 30 40 50 60 70 80
Volume of Shale
Average Porosity
Effective Porosity
Saturation of Water
Saturation of Hydrocarbons
Depth(ft)

60. Formation
Name
Lithology Volume Of
Shale
(%)
Average
Porosity
(%)
Effective
Porosity
(%)
Avg. Water
Saturation
(%)
Avg, Hydro
carbon
Saturation
(%)
Chorgali
Formation
Limestone,
Shale
33.80
%
10.81
%
7.34
%
26.33
%
73.66
%
Lockhart
Formation
Limestone,
Marl
32.55
%
9.84
%
7.56
%
42.6
%
57.4
%

61. RESERVOIR ESTIMATION
 The total estimated amount of oil in a reservoir, including both
producible and non-producible oil, is called oil in place.

62. C.I. 20 ft
S.R.D
400 m

63. N = 7758 * GRV * N/G * Φ * So * 1/Bo
Where
7785 = Conversion factor (acre-ft*7758 =barrels)
GRV = Gross Rock Volume (acre-ft)
N/G = Net to Gross Ratio (decimal)
Φ = Porosity of this net reservoir rock (decimal)
So = Oil Saturation (decimal)
Bo = Formation Volume factor.
VOLUMETRIC RESERVE ESTIMATION

64. RESULT OF VOLUMETRIC RESERVES
Reserve Calculation
(7758*Area(acre)*Net Pay(ft)*Avg. Porosity(phi)*Sw)/Bg
Formation Case Contour
Area
(Acre)
Net Pay
(ft)
Phi avg.
(fraction)
Sw avg.
(fraction)
Bo
OIIP
(MMBL)
Recovery
Factor
Recoverable
Reserves
(MMBL)
GOR
(scf/stb)
Gas
Recovery
(BCF)
Chorgali
P90 2470 3706 130 0.05 0.28 2.047 65 30 19.5 1975 38512.5
P50 2600 6177 130 0.05 0.28 2.047 109 30 32.7 1975 64582.5
P10 2700 9884 130 0.05 0.28 2.047 175 30 52.5 1975 103687.5

65. CONCLUSIONS
 The multifold seismic acquired by OXY and POL demonstrated that Dhulian
subsurface structure is more complicated than what was originally thought.
 The structure is a three way dip closure bounded by thrust fault.
 Based on this new seismic evidence, Dhulian structure was proved to be a
thrust-bounded salt-cored anticline.
 It is cut across by a major wrench fault that splits Dhulian into two major fault
blocks.

66. RECOMMENDATIONS
 For more detailed study and to define potential sites in the area, more
seismic lines are required.
 High resolution seismic data and wire line logs should be acquire in future
operations.
 3D seismic survey should acquire in future to obtain the maximum
information of subsurface.

67. REFERENCES
 Dolan P., (1990) Pakistan: a history of petroleum
exploration and future potential; in Classic
Petroleum province edited by Brooks J. Special
Publication of The Geological Society London
 Iqbal B. Kadri, (1995), Petroleum Geology of
Pakistan
 Khan M. A. Ahmed R., Raza H. A., and Kemal A.,
(1986), Geology of Petroleum in Kohat-Potwar
depression, Pakistan, AAPG Bulletin, Vol 70, No. 4
 Iqbal, M.W.S, and Shah, S.M.I, 1980. A guide to the
Stratigraphy of Pakistan.V.53

68. Thank You

69. Annexure
Structural Model of Dhulian