1. Small scale reflection seismology

2. CMP gather

3. 3D seismic reflection

4. The goal is a 3D image of structure (data cube)

5. Visualization (slice & dice)
3-D image
Visualization (slice & dice)
Volume construction of salt dome image

6. Typical Geometry for 3D Acquisition

7. Acquisition Animation Courtesy of PetroSkills
Marine
Acquisition Animation
(Bin Gathering)
Courtesy of PetroSkills

8. Marine 3D Acquisition

9. Marine 3D Acquisition

10. Marine 3D Acquisition

11. Marine 3D Acquisition

12. Marine 3D Acquisition

13. Marine 3D Acquisition

14. Marine 3D Acquisition

15. Marine 3D Acquisition

16. Marine 3D Acquisition

17. Marine 3D Acquisition
Traces in
Each Bin 16 14 12 10 8 6 4 2

18. Marine 3D Acquisition
Mid-
Points

19. Marine 3D Acquisition
Mid-
Points
Inline
Crossline
Stacked
Trace

20. Seismic Interpretation
Integration of seismic data with other constraints on the geology
well logs
outcrop patterns
known stratigraphy, faults, etc
Important to remember what seismology provides:
imaging of interfaces between beds of different velocity
detailed constraints on the geometry of these interfaces
What seismology does not provide:
unique identification of rock type
usually does not provide direct imaging of petroleum, gas, water, etc
Thus:
seismic data is much more useful along with other constraints on
geology providing identification of the interfaces.

21. Caliper – measures borehole size Lithology Logs – differentiate sands
Overview of Key Logs
Caliper – measures borehole size
Lithology Logs – differentiate sands
Porosity Logs – porosity & fluid types
Sonic Logs – relate well to seismic
Resistivity Logs – Identify HC zones
SLIDE 3
We will briefly look at these 5 classes of key logs
Courtesy of ExxonMobil
L 4 - Well Log Data

22. Porosity Logs Shale Density porosity (solid black line)
Neutron Porosity
Density porosity (solid black line)
measure the bulk (average) density of the formation (rock & fluids)
Neutron porosity (dashed red line)
measures the hydrogen content
Shale
Deflections to the left = more porous
Deflections to the right = less porous
Dashed red left of Solid black black = Shale
Dashed red right of Solid black = Gas Sand
Dashed red over Solid black = Wet Sand or Oil Sand
SLIDE 7
This slide introduces two porosity logs
Density porosity (solid black line)
measure the bulk (average) density of the formation (rock & fluids)
Neutron porosity (dashed red line)
measures the hydrogen content
For both logs,
Deflections to the left = more porous
Deflections to the right = less porous
The way we interpret these logs is to draw them together (in the same track)
If the dashed red line is to the LEFT of the solid black line = Shale
If the dashed red line is to the RIGHT of the solid black line = Gas Sand
If the dashed red approximately overlies the solid black line = Wet Sand or Oil Sand
Gas
Gas
Oil or
H2O
Courtesy of ExxonMobil
L 4 - Well Log Data