1. Why Pre- Stack Data? by Kristian Kolbjørnsen (DNO) and Arild Haugen (NPD) FORCE seminar 6.2.2002

2. Pre-Stack Data Introduction History Logistics Processing Applications
Actions/Suggestions

3. Introduction Seismoscope (132 ad) Newton Hilbert/Gödel
Infomation/Exfomation:
crucial for all communication
??..?

4. Les Miserables ?

5. Les Miserables !

6. History Analog period < 1960+; Pre-stack only!
CDP concept ~ 1960’ies
Digital technology >1960
Increased density in time and space
3D ~ 1980
Sophisticated processing
Wave eq. Mig, ~ 1980

7. To pile something in a (conical) heap.
Ethymology: Stack
Stack, from Old-Norwegian stakkr stak stakk (Swedish: stack)
To pile something in a (conical) heap.
Stakk
Høystakk
Rifle Stack
Stakkitt
KongeStakk
Kortstokk

8. Usage of Pre-Stack Data
Examples:
Data enhancements (Statics, filtering, CDP stack etc )
Velocity analysis: Taner and Koeler (1969) - ProMax (1985)  Today; same basic technology
GSI 700 package!

9. What’s lost? Stacked data loaded toWorkstations
1:1000 (4 ms, 25m, 60 fold, 8 bit)
Are we paying for more than we use?
Refractions
Reflections
Noise
Shot from the Paris Basin

10. What is hidden?
Something MUST be hidden or at worst lost

11. How much info can we receive?
Info received through eye: 10 Mbps
Human brain extracts only 14 bps
(Nørretranders, 1993)
Age 50
100
Age

12. What can be revealed? Zi, Vp, Vs ….. λ μ ρ p , Φ , So, Sw…
λ μ ρ
p , Φ , So, Sw…
                                           
Aroma, Bouquet,
Taste….
Stringent høye bærtoner

13. Post-Stack State-of-the-art
Modern visualisation of post stack data a major step in the right direction
New Paradigm
Colour and motion assist the human brain in recognising patterns by rapid scans through the 3D cube
However: Only the creative and experienced interpreter will be able to find Zen in the art of interpretation
Geoprobe/Magic Earth

14. Data power
For planning the future ALWAYS keep in mind the IT development curve
There are no signs that this will change

15. 1:1000
99,9 % of the data represents a potential

16. Accessing pre-stack data
Lost time: 4-8 weeks
Costs:
Expensive reprocessing
Expensive copying
Example from DNO2002:

17. Philosophy Properly stored and easy access Standard formats (i.e.SEGY)
Indexed
Edited only (traceable)
”Standard” processing sequence (traceable)
=>PETROBANK
Appellation d’Origine Controlee
French wine-standards

18. Reasons not to store pre-stack data?
Cost?
Cumbersome?
Conservativism?
Contractor opposition?
Complete waste?
Ignorance?
Politics?
Strategy?
Cooperation is for communists!

19. Reasons to store Pre-stack data in Petrobank
IT price-performance development (Rio)
Prestack only 100 x poststack
Proper storing costs only a fraction of acquisition costs
Access
Prevent data media degradation
Backup
Data cleaning and QC
Time is money….

20. Storing Pre-stack data
Data volume not an issue
NPD can regulate the treatment of pre-stack data along the same guidelines as post-stack:
For this afternoons discussion:
Define pre-stack data as a part of the National Dataset

21. The search for Zp, Vp and Vs
Topics:
Wave Equation vs Ray Based (EAGE workshop)
Kirchhoff becoming state-of-the art (Clustered Linux/PCs)
Transverse Isotropic media with a Vertical axis of symmetri (VTI) – Leon Thomson
Angle Stack/Migration
Full Elastic Inversion vs Near/Far stack inversion
AVO
Clustering
Velocities
Workstations/Visualisation

22. Summary and key factors for success
Easy access
Visualisation
Applications
User interface
Availability will stimulate many new ideas!
The Pre-Stack era has just started

23. Thank you!

24. Proposal FORCE to initiate a project/work group
Members: Authorities, Oil Companies and Contractors
Mandate:
Refine/Extract ideas from the seminar
If necessary define pilot project(s)
Propose an action plan for the treatment of PSD
Discuss with NPD and OLF’s and FORCE’s seismic work groups