Ageing Assets: Viable options to mitigate corrosion using ...

© Flexlife 2016ENGINEERING • DELIVERY • INTEGRITY • TECHNOLOGY

Subsea Springboard

Ageing Assets:

Viable options to mitigate corrosion using advanced polymeric solutions

1© Flexlife 2017


Background

2

• Increasing demands being placed upon

infrastructure due to field life extension

• Increasing financial pressure due to lower

oil/gas prices

• Requirement to address integrity concerns

– Safely

– Innovatively

– Cost Effectively

• Corrosion within I-J Tubes

• Temporary Pipeline Isolation

• Leaking/Passing Lower J-tube Seals


FlexGelLD - Riser Corrosion Protection Case Study

3

• 2 rigid risers routed through a J-tube,

UKCS platform

• WI riser suffered catastrophic failure

due to CUI (Corrosion Under Insulation)

• Adjacent GL riser inspected and found

to have significant wall loss in the

splash zone

• Options

• Replace J-tube

• >£2m

• FlexGelLD

• £120k

Camera Image B.22: View on riser showing disbondment

Camera Image B.23: View on riser showing disbondment at FlexGel level

Talisman Tartan Alpha FlexGel Deployment Report

Doc. No: FLX-TAL-002-PRO-15635-r1 Page 29 of 35

Camera Image B.22: View on riser showing disbondment

Camera Image B.23: View on riser showing disbondment at FlexGel level

Talisman Tartan Alpha FlexGel Deployment Report

Doc. No: FLX-TAL-002-PRO-15635-r1 Page 29 of 35



4

• Displacement of Seawater

• Replacing seawater with non corrosive gel

• FlexGel®

• Developed to prevent corrosion of risers in I tubes and

Caissons

• Immiscible in water

• Non flammable

• Density is ‘tuned’ to prevent oxygen reaching breach

site(s)

• Contains biocide to also arrest Microbial Induced

Corrosion MIC

• Arrests all corrosion

• Approved by OCNS



5

• Camera and hose tethered as FlexGel® pumping

takes place

• FlexGel® displaces water line within I-tube

• Moves within I-tube according to tidal range

• Unaffected by short period wave action

• Prevents further corrosion of damaged pipe

• Schedule inspection regime to ensure Gel remains

intact



6


FlexGelXLD – Pipeline Isolation Case Study

7

• Leaking rundownline within confines of platform leg,

-70m below gas tight floor

• Inaccessible

• Hazardous location

• Emergency mobilisation

• 12 days from initial discussion to offshore

mobilisation

• Adaptation of FlexGelLD Product

• Tuned SG

• Cross-Linking Chemical

• Injected as a liquid

• Cures to form an elastic solid


FlexGelXLD – Pipeline Isolation Case Study

8

GLS$$4$m3$

L(Gel$Base$4.5$m3$

L(Gel$Base$4.5$m3$

Mixing$IBC$1$

2’’$Diaphragm$Pump$

2’’$Sureclean$Pump$

2’’$Sureclean$Pump$

3’’$inlet/$2’’$Outlet$Sureclean$Pump$

Mixing$IBC$2$

Hoses$

Mixing$Skip$

Mixer$

Tote$Tanks$

Pump$

16’’$P1007$

Pipe$Deck$EL+$192$m$

2’’Valve$EL$+98$m$

• FlexGelXLD installed into rundownline

• Production reinstated

• Repaired externally

• FlexGelXLD blown out of rundownline into subsea cells

© Flexlife 2016ENGINEERING • DELIVERY • INTEGRITY • TECHNOLOGY 9

Innovative Polymer Based Solutions

• For discussion:

• FPSO Flexible riser, within I-

tube damaged at splash

zone

• Or J-tube with passing lower

seal leading to inhibitor

leaching and corrosion

© Flexlife 2016ENGINEERING • DELIVERY • INTEGRITY • TECHNOLOGY10


• Inject floating, liquid

FlexGel XLD

• Comprises base chemical

• Plus activator

• Injected from topsides



• Overtop FlexGelXLD with

FlexGelLD

• Or, benign liquid with lower

SG than FlexGelXLD



• FlexGelXLD is held in position by FlexGelLD

• Minimal differential pressure

• Unaffected by changing vessel draft

• FlexGelXLD cross-links forming an elastic, solid, ploymeric plug at J-tube base

• No need for replacement– Or vessel intervention

• Internal inspection still possible.

Ageing Assets: Viable options to mitigate corrosion using ...

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