1. 1 -Classification: Internal 2010-11-19 Corrosion protection of off-shore steel pipes by retrofitting felt- epoxy liners, a method qualification of Insituform™

2. 2 -Classification: Internal 2010-11-19 Background Since start-up in 1986 less oil, more gas and more water are being produced at Gullfaks Less demand for oil storage capacity Re-assign oil storage tanks to produced water settling tanks

3. 3 -Classification: Internal 2010-11-19 Challenges Carbon steel piping from utility shaft to storage cells −Crude oil OK −Produced water corrosive Piping cannot be replaced Corrosion protection essential One-sided access only Long and intricate routing of pipes Pipe failure or blockage → loss of storage cell

4. 4 -Classification: Internal 2010-11-19 Considerations Internal painting ruled out −Surface preparation extremely difficult −Paint application −Inspection Cathodic protection ruled out −Temperature, Oxygen, Chlorides and Sulfides −Uncharted territory Liner most favoured solution

5. 5 -Classification: Internal 2010-11-19 Liner Requirements Loose liner ruled out → rigid liner Compliant during placement → thermoset based Adhesion to pipe surface cannot be critical → structural liner Be able to ensure position of liner end → non-stretch liner Ample ‘pot-life’ → epoxy ‘What if’ contingencies → ensure back-up solutions for relevant failures during installation

6. 6 -Classification: Internal 2010-11-19 Insituform™ from Olimb AS Thermoset liner based on felt and epoxy Felt thickness can be tailored to give appropriate structural capacity Epoxy quality can be chosen to give temperature and chemical performance (NA) Inserted (inverted) into pipe using compressed air Cured using steam Mature product in terms of renovating municipal piping Less history on complex geometries Ensure most demanding relining is well within the process window → do a test relining of replica of most challenging pipe on land

7. 7 -Classification: Internal 2010-11-19 Pipe replica Length of chosen pipe approx 80 metres Pipe diameter 16’’ Starts off with 3 x 90º bends then 12 m straight up Then 10 more bends

8. 8 -Classification: Internal 2010-11-19 In a quarry near Moss

9. 9 -Classification: Internal 2010-11-19 The liner principles A tubular felt sheath clad with a layer of PU on the outside Prior to placing the liner in the pipe, the felt is saturated with epoxy Even distribution of epoxy using rollers Curing can be delayed by placing in cold water

10. 10 -Classification: Internal 2010-11-19 The liner principles Silicone ‘plug’ loosely glued to end of liner Perforated to allow controlled escape of steam Glue must allow pull-off by attached rope after curing

11. 11 -Classification: Internal 2010-11-19 Liner reeled Lubricant applied to outer surface Rope and liner reeled up inside pressure vessel

12. 12 -Classification: Internal 2010-11-19 Inverting the liner Rope and liner reeled up inside pressure vessel End of liner pulled back over spout Tank pressurised to force liner into pipe

13. 13 -Classification: Internal 2010-11-19 A sketchy illustration... Pressure vessel Liner Corroded pipe o → →

14. 14 -Classification: Internal 2010-11-19 Results Maximum recorded pressure 1.2 barg −Allowable 1.5 barg −Burst 2.5 barg All bends negotiated first attempt Curing temperature achieved at far end Silicone ‘plug’ came off (no force measurements were done) End of liner within tolerances No contingency plans were put into action

15. 15 -Classification: Internal 2010-11-19 Results Destructive inspection of pipe revealed Wrinkles at the bends Some lack of adhesion to the steel Minor liner thickness variations The method is deemed successfully qualified for this application

16. 16 -Classification: Internal 2010-11-19 Corrosion protection of off-shore steel pipes by retrofitting felt-epoxy liners, a method qualification of Insituform™ Gunnar Hognestad Principal Engineer guhog@statoil.com www.statoil.com Thank you