This document presents a seismic interpretation and attributes analysis of the Dhodak Gas/Condensate field in central Pakistan. The objectives were to delineate subsurface horizons, identify faults, and generate time and depth contour maps. Key findings include: 1) The main source rock is the Sembar Shale, and the reservoir is the Pab Sandstone. Reflectors were identified as the Dunghan Formation, Lower Ranikot Formation, and Pab Sandstone using a synthetic seismogram. 2) Interpretation of three seismic lines identified thrust faults across the area and a pop-up structure. 3) Time and depth contour maps were generated for the three formations to locate probable well

2. 2D Seismic
Interpretation and Attributes Analysis
of Dhodak Gas/Condensate field,
Central Indus Basin, Pakistan
Presented by Hakmatyar Ahmad
(Bacha khan university charsadda)
Supervised by Mr.Matee Ullah
(Lecturer at Khushal khan Khattak university karak)

3. Project Outlines
Introduction of the Area
Location
Data Obtained
Formation Tops
Objectives
Methodology
Geology of the Area
Tectonic Map of Pakistan
Local Tectonic
Stratigraphy
Petroleum Plays
2D Seismic Data Interpretation Analysis
Base Map
Fault Polygon

4. Project Outlines
Generation of Synthetic Seismogram
Marked Reflectors Information
Interpretation of Seismic Sections
Time Contouring Maps
Depth Contouring Maps
Attribute Analysis
Phase Attribute
Average Energy Attribute
Frequency Attribute
Envelop Attribute
Conclusion

5. INTRODUCTION OF THE AREA

6. Location
Dhodak Condensate and Gas
Field is the northern most
Culmination of the Sufaid Koh
Situated on the eastern margin of
the Suleiman Ranges about
80 km of the Dera Ghazi Khan
City Punjab Provence.
Tectonic map of Pakistan.

7. Data Obtained
Seismic Lines Data Provided by the DGPC
Seismic Lines Data
Line Name Line
Nature
Line
Orientation
Shot Point Total Shot
Point
GO-795-SK-
06
Strike Line North-South 110-300 190
GO-795-SK-
11A
Dip Line East-West 110-190 80
GO-805-SK-
19
Dip Line East-West 110-250 140

8. Data Obtained
Well Log’s Data Provided by the DGPC
Well Logs of Dhodak Well # 1
Lace Files Data Dhodak Well # 1
Calliper Log Present
Gama Ray Log Present
SP Log Present
Resistivity Log Present
Density Log Present
Neutron Porosity Log Present
Sonic Log Present
ASN Log Present
DRHO Log Present
SN Log Present
MINOR Log Present

9. Objectives
 To delineate the subsurface target horizons on the seismic lines by
using the synthetic seismogram in the seismic interpretation.
Identification of Faults.
Time and depth contour maps generation in order to locate probable
well location.
Attribute Analysis are done by using the following attributes to
delineate the subsurface structures.
Frequency Attribute
Phase Attribute
Envelop Attribute
Average Energy Attribute

10. Methodology
To make a detailed critical inspection about geology tectonics of this
region.
Distinguishing to perform the real reflectors on the seismic section.
With the help of seismic sections the faults will be marked.
The arrangement of Time and Depth contours of noticeable
reflectors.
Finding a solution for velocity windows to judgments a probable
depth.
According to seismic survey the Base map of Dhodak well 01 have
been made ready.
Explanations to interpreting the Attributes attempts are done.

11. GEOLOGY OF THE AREA

12. Tectonic Map of Pakistan

13. Local Tectonic Map of Central Indus Basin

14. Stratigraphic Chart of the Area

15. Petroleum Plays in the Area
 Source Rock:
In the Dhodak Field the main Source rock is the Sembar Shale of
cretaceous age. Other source rocks which are present in the Lower
Indus Basin are the Ranikot shale, Ghazij shale, Coal and Shale of the
Nari Formation and Moghalkot Formation.
 Reservoir Rock:
Reservoir rock of the area is Pab Sand(Cretaceous) Stone in the
Dhodak Field. Other Reservoir rock are Guru Formation(Lower
Cretaceous), Bara Formation(Middle Paleocene) and Lakki
Limestone Formation (Early Eocene).
 Seal Rock:
Upper Ranikot is the seal rock of the area.

16. 2D SEISMIC INTERPRETATION

17. Base Map of the Area

18. Miss tie and Fault Polygon

19. Generation of Synthetic Seismogram

20. Marked Reflector’s Information
FORMATION DEPTH TIME VELOCITY
DUNGHAN FM 1834 1.54 2348
LOWER
RANIKOT FM
1929 1.62 2375.6
PAB FM 2095 1.69 2450.2

21. Interpretation of the Strike Line#GO-795-Sk-06

22. Interpretation of Dip Line # GO-795-SK-11A

23. Interpretation of Dip Line # GO-SK-805-19

24. TIME AND DEPTH CONTOURS MAP

25. Time Contour Map
 Contouring is “The imaginary line that exhibiting the same
parameter on 2D map such as depth , time, elevation etc.
 Here with the help of time rate contours are created which is that
time of the wave which reflect backs due to the change in density
contrast of the subsurface strata are change in acoustic impedance.
 The Time contours are initiated for every reflectors on map.
 In our research the time contour maps of the three essential
reflectors are on three seismic section are projected on the base
map.

26. Time Contour map
The time contour map of the Dunghan formation.

27. Time Contour Map
Time Contour Map of Lower Ranikot Formation.

28. Time Contour Map
The Time Contour Map of Pab Formation.

29. Depth Contour Map
 The depth contour map point out the structures of the area as well as
contributes the overall information’s about the depth along with its
range of precise formation.
 The given up depth contour maps are originated with the help of the
reflection time rates of the seismic lines of the Dhodak area that
containing the GO-795-SK-06, GO-795-SK-11A and GO-805-SK-
19 as point out in the consequential pattern.
 The depth contour contribute us to help in the conception about 3-
Dimensional structure of the peculiar lithology that pointing out its
depth as a surface.

30. Depth Contour Map
The Depth Contour map of the Dunghan Formation.

31. Depth Contour Map
The depth contour map of the Lower Ranikot Formation.

32. Depth Contour Map
The Depth Contour map of the Pab Formation.

33. Time Surface map
Time Surface Map of Pab Formation

34. Attributes Analysis

35. Introduction to an Attributes
 An Attributes are the essential pieces of information observe within a
recorded seismic trace, frequency, amplitude, time and attenuation is
known as Seismic attributes (Brown, 2001).
 Attributes analysis used for the identification of seismic facies,
depositional environments, bedding indicator, unconformities,
continuity and discontinuity of lithology, hydrocarbon indicator and to
determine the geometry of a buried rock body that is normally be
under the seismic resolution but here the attribute are used for fault
analysis.

36. Frequency Attribute

37. Phase Attribute

38. Trace Envelop Attribute

39. Average Energy Attribute

40. Conclusion
Seismic Interpretation is mainly done on the basis of the available
information and the stratigraphy of the area.
In my area source rock is Sember Shale, Reservoier rock is Pab
Sandstone while seal rock is Upper Ranikote Shale.
Reflectors are marked and then conformed on the basis of Synthetic
Seismogram which are Dunghan Formation, Lower Ranikot
Formaton and Pab Sandstone.
In Seismic Interpretation Time and Depth contour maps of the all
Formations were generated by using the Kingdom Software.
The Study Area is a Compressional Regime Thrust Faults are
dominated all over the area along with Pop Up Structure.

41. THANKS