1. Tail production: Choosing the right strategy for Produced Water Management K.I. Andersen

2. Produced Water Daily Volumes Statfjord 160 000 m3/d Gullfaks 75 000 m3/d Snorre 25 000 m3/d Tordis/Vigdis 15 000 m3/d Veslefrikk 15 000 m3/d Heidrun 10 000 m3/d Norne 2 000 m3/d Åsgard 500 m3/d

3. 300 000 m3/d of produced water..

4. Mars April 2004

5. Oil rate development 2003 vs 1998 All GF and SF wells

6. Water rates pr. well 2003 vs 1998 All GF/SF

7. Increased watercut : scale, reinjection, water shutoff, downhole separation

8. Environmental impact (EIF) at Statfjord C

9. Environmental impact (EIF) at Gullfaks A Gullfaks A 2002

10. Produced Water Management Water shut off Re-injection Produced water treatment

11. Authorities, Produced Water and Environment: Reduced Tolerance vs.

12. Produced Water Handling Principles 1. Improve use of chemicals 2. Reduce at source Isolate water producing zones (plug, patch, gel) Intelligent completions Downhole separation 3. ReinjectProduced water reinjection in active reservoir 4. StoreUtsira or depleted/non active areas of field 5. Purifiy before dischargeCTour, EPCON etc

13. §1. Reduce chemical consumption or change to non-toxic

14. H2S-removal by use of scavenger

15. Environmentally friendly H2S removal ProPure C100 installed at Åsgard B May 2001 –Low capital cost Performance test in 2002 –30 % reduction in chemical consumption –Low pressure drop (0.2 bar) Installed at Huldra, Veslefrikk, and Gullfaks B in 2002 Installation at Gullfaks A and C in 2003

16. § 2. Shut off waterproduction at source

17. Well completion type dictates water shutoff complexity Horizontal, screen Horizontal, cased Cased Screen

18. Main Well Categories in Statoil (total +-700 wells) Perforated,cement deviated Openhole, deviated Perforated, cemented, horiz. Openhole horizontal Complexity, zonal isolation 60 % 5% 25% 10 %

19. - Cumulative annual water shut off 25 000 m3/d

20. Ongoing R&D : Revisiting chemical route to water shutoff

21. Chemical water shutoff/Emulsified gel technology DPR- ”Classic” i.e. polymer ”Strong gel” e.g. H2Zero

22. Rate effects of changing PI and WC

23. R&D continued: Downhole separation - ’light’ version Objective : Research of slip gravity separator concept for downhole separation. By controlling the stratified layers between oil and water in an inclined tube, the layers can be controlled to segregate through specially designed slots in the tubing wall. Demo 2000 project - ABB, Statoil, Shell Technology and NTNU.

24. Future : Subsea Separation and PWRI

25. §3. Reinject water (PWRI)

26. A-43 PWRI performance

27. Statfjord field map pilot well

28. - Today reinjecting 30 000 m3 of water

29. R&D - PWRI Fracture growth : improving our modelling capability

30. §3. Dispose into aquifer

31. Utsira – a shallow saltwater reservoir

32. Extent of Utsira aquifer

33. - Kvitebjørn to dispose all produced water into Utsira

34. §4. Purify and discharge

35. Distribution of organic components in produced water WAF= Water accommodated fraction

36. The CTour process

37. Results from CTour test at Statfjord B These component groups are together with our corrosion inhibitor the largest contributors to EIF Blue line system performance (with hydrocyclones), red line effect of condensate and mixers only

38. Questions?