Research Proposal Defense

1. Research Proposal Defence
Research Title
Illumination Based Seismic Imaging of
fractured basement using Wave theory
Yasir Bashir (PhD in Petroleum Geoscience)
Supervisor: Prof. Dr. Deva Ghosh
Co-Supervisor: Dr. Chow Weng Sum
1

2. Outline
• Introduction
• Problem Statement
• Objectives
• Literature Review
• Case study
• Methodology
• Preliminary Results
• Time Line
• References
• Comments and Suggestions
2

3. Introduction
3
• Geophysical Challenge in Malay and adjacent basin.
• In Basement Seismic Imaging is affected by
• Lack of bedding
• Highly dipping fault and fracture
• Small impedance contrast
• Basement heterogeneity
• Fracture Distribution
• Their connectivity
• Lateral variation
• Difference between good and dry well?
• Regular Seismic methods
• Wave-Equation Migration. (One-way and two-way)

4. Literature Review
 Geology of Malay Basin
• Malay Basin, a northward-trending
pull-apart extensional rift basin.
• Formed during the late Eocene-early
Oligocene
• Underwent thermal subsidence and
sedimentation during the early Miocene.
• Groups starting from the youngest (A) to
the oldest (M).
• Exploration currently focuses primarily
on groups E–K.
4

5.  China: Daminton depression-produced oil
from fractured metamorphic (500m oil
column).
 Thailand: Phitsanulok basin, produced oil
from fractured Metamorphic
 Vietnam: Cuu Long basin, oil from
fractured granite.
 Indonesia: Central Sumatra and South
Sumatra basins, oil/gas from fractured
Metamorphic/granite.
 Algeria: Ghadamas basin, oil from
fractured Cambrian sandstone.
 Malaysia: Malay basin, oil from fractured
metamorphic. Future remaining play in
Carigali exploration acreages. Sudan, elut
basin, heavy oil from fractured granite.
 Anding Utra: Fractured Jurassic Metamorphic
Basement
Literature Review Cont.…
List of countries proven play
in fracture reservoir
Petroleum geology and resources of Malaysia
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6. Problem Statement
 Reflection event form the basement can not image properly
in regular seismic data processing technique.
 Reliable methods/algorithms are required to illuminate the
fracture basement.
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7. Objectives
Better definition of faults/fracture zones inside Meta-sediment
Basement through
 Careful pre image processing.
 Develop Appropriate and reliable Depth Migration
Algorithm and apply for fracture basement imaging.
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8. Classification of Seismic Imaging
Acoustic Wave
Equation
Wave Eq. Method
(WEM)
Continuation
Green’s Function
In Depth
In Time
Kirchhoff Eikonal
Ray Trace
Minimum Time
Multiple
Path
Finite
Difference
Full
High Frequency
Literature Review Cont.…
Seismic Imaging
Classification
Wave Theory
Or
Ray Theory
Isotropic
Or
Anisotropic
Acoustic
Or Elastic
Or Inelastic
( Q )
2D
3D
4D
D.P. Ghosh 8

9. Complexitycomparison (Migration Methods)
Kirchhoff
PSTM
“full” Beam
PSDM
WEM
Kirchhoff
PSDM
Reverse Time
Migration (RTM)
“Fast” Beams
9
Literature Review Cont.…
Angle of Dipping 800

10. Acoustic Wave Theory (derivation of wave equation)
Hooke’s Law : Volume change is proportional to pressure
(1)
Newton’s Law : Net Force is equals to mass times acceleration
(2)
Using Δ m = ρ v
(3)
Combining (1) and (3) we have the Wave Equation as :
= 0 where, c²= k / ρ (4)
Taking Fourier Transform of (4) we get:
(5)
Which is known as the Helmholtz Equation
10
Literature Review Cont.…

11. 11
Comparison Between One-Way and Two-Way
Wave Equation using 2 layer Model

12. Case Study Cont....
Application of One-way and Two-way wave
equation
Velocity model with an interface at a dip
angle of 60◦.
Migration images for a dipped interface at 40◦. At
this dip, the one-way migration still produces an
acceptable result.
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Angle of Dipping 400

13. Case Study Cont....
Comparison between angle Of Dipping
Migration images for a dipped interface at 60◦. At
this dip, the one-way migration still produces an
acceptable result.
One-way migration breaks down and two-way
migration still reproduces the dipped interface but
suffers from illumination problems.
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Angle of Dipping 600 Angle of Dipping 800

14. 14
Case Study Cont....
Results from cuu long basin (Vitname)
Figure. Comparison of 2002 and 2006 Kirchhoff depth migration on a vertical section
Figure. Comparison of 2002 and 2006 CBM depth migration on a vertical section
 Both Migration
Methods
 Improvement in 2006
Limitation
 Kirchhoff
 CBM
Results
 CBM is used to image
the top of basement
and fracture inside the
basement by applying
different velocity
model.
(Pham, Sun et al. 2007)

15. Conclusions
 Time Slice showing better imaging inside the basement fracture.
Case Study Cont....
 Controlled Beam Migration (CBM) gives the good result to image the top of the
basement and the fractures inside the basement. The image quality of CBM is
superior to that of Kirchhoff migration.
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Figure . Comparison of 2002 and 2006 CBM depth migration on time slices

16. Scope of Research
 The results obtained from research will be helpful in
selecting the best methods for imaging the fracture
basement.
 The results will be help to image the fracture basement
and adjacent formation including complex structure and
boundaries which are poorly resolved using regular
seismic processing techniques.
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17. Methodology

18. Preliminary Results
Wave Propagation In 2 layer model
 For getting preliminary results I use the velocity and density model to propagate the
wave.
 2 layer model one is horizontal layer and other is dipping layer at 60 degree.
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19. Kirchhoff PSTM on a two layer model
Figure. Showing velocity model and geometry of
source receiver
Figure. Showing processed gather before migration
Figure. After applying the KPSTMmigration
Preliminary Results
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Conclusion
Kirchhoff PSTM couldn’t illuminate because
of dipping angle, So wave equation gives the
satisfactory results in this case.

20. 
Double Radical Equation:
Preliminary Results
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21. Diffraction curves
Preliminary Results
Diffraction behavior, velocity= 2000 m/sec diffraction behavior, velocity= 3000 m/sec
Diffraction behavior, velocity= 4000 m/sec Diffraction behavior, velocity= 5000 m/sec

22. Diffraction Curves
Preliminary Results
Diffraction Behavior, velocity= 2000 m/sec diffraction Behavior, velocity= 3500 m/sec
Diffraction Behavior, velocity= 5000 m/sec
On X-axis we have offset in km and Y-axis time in second.
So the result and observation from this diffraction curve are
as under.
Conclusion
 Only velocity does not effect on diffraction but depth
also.
 If velocity is constant and depth is increasing then
diffraction curve spread out and curvature will decrease.
 Diffraction give a hyperbola on the edge of the reflector
also on the whole reflector points but because of phase
change they cancel out only edge hyperbola remain.

23. Seismic Response to Geology
(Diffraction Example)
Seismic Response
Geology
Inverse Process
Forward Process

24. Time Line
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25. 25
Comments
&
Suggestions

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