1. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 STRUCTURE AND DISTRIBUTION OF GAS HYDRATES IN MARINE SEDIMENTS Contribution 4, by: F. Abegg, G. Bohrmann, GEOMAR J. Freitag & S. Kipfstuhl, AWI

2. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Introduction Objectives, techniques, working areas Examples of different internal gas hydrate structures Quantification of gas hydrate, free gas and host sediment A frozen core from the Black Sea A pressurised core from Hydrate Ridge Conclusions

3. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Tool: X-Ray CT scanner

4. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Frozen gas hydrate sample in a foam box

5. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Black Sea: core location

6. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Hydrate Ridge: core location

7. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Sample SO148-11

8. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Honeycomb structure 20 mm gas hydrate (light grey) mud (dark grey) carbonate (black spots)

9. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Sample SO148-20

10. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Dense gas hydrate 40 mm

11. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Sample SO148-14

12. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Alternating layers 50 mm

13. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 SO148-5: 3-D using 227 slices

14. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 SO148-5: 3-D cutout

15. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Example of thresholding

16. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Quantification of components Example from sample SO148-11

17. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Frozen core from the Black Sea

18. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Various analyses 3-D gas hydrate

19. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 MultiAutoklavCorer

20. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Pressurised? YES!!

21. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 LabTransferChamber positioned in CT scanner

22. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Results LTC4

23. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 shell/carbonate gas hydrate gas mud 10 cm subseafloor depth 27 cm subseafloor depth 29 cm subseafloor depth Slices from LTC4

24. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 2-D and 3-D

25. 7th Shallow Gas Group Meeting Baku, Azerbaijan, 07.10. – 11.10.2002 Conclusions CT is an appropriate tool to quantify gas hydrate, gas and host sediment on a mm-scale and to determine internal structures Together with autoclave technology the above is possible close to in situ conditions A frozen core from the Sorokin Trough shows gas hydrates in elongated near-vertical, crack-like features In situ gas hydrate concentration at Hydrate Ridge reaches 50 Vol.% in a horizontal layer with a gas content of up to 10 Vol.% Thank you very much for your attention! respond to: fabegg@geomar.de