Business Case

New treaths

New knowledge

System

description

Production

forcast

Design BasisExternal loads

- Environmental

load

- 3rd party loads

Risk assessmentFuture Operation

Determine Condition

Assessment / Studies

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New Design Life

Ext Service LifeOrg Service Life

LTE project

Operational

Inspection

Modification

Time

Mitig

atio

ns

Org Design Life

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- 20” pipeline – carbon steel

- 18 years design life – expired in 2009

- Operated from 1991 – 2002

- Gas condensate

- Injection of methanol (MeOH) and

corrosion inhibitor

- Corrosion allowance 3 and 5 mm

- Designed according to DNV’81

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0

10

20

30

40

50

60

0 10 20 30 40 50

KP from Oseberg [m]

Te

mp

era

ture

[°C

]

New service Old Service

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Parameter Unit Value

Lateral buckling At KP 44

Anode consumption % 0 - 30

Free spans % 44

Longest span m 40-50m

Free spans % 44

Other observations Anode pitting from KP ~

44 000 m –

ER- PROBER

SYSTEM 30, OSA

0

50

100

150

200

250

1993

-Jan

1993

-Mar

1993

-Jul

1993

-Sep

1993

-Nov

1994

-Jan

1994

-May

1994

-Aug

1995

-Jul

1995

-Sep

1995

-Oct

1996

-Jan

1996

-Mar

1996

-Jul

1996

-Nov

1997

-Jul

1996

-Nov

1998

-Mar

1998

-Jul

1998

-Dec

2000

-Feb

2000

-Jun

2000

-Oct

2001

-Feb

2001

-Oct

2002

-Feb

2002

-Jun

2002

-Oct

2003

-Feb

Accu

mu

lative

co

rro

sio

n [µ

m]

30-CE-001 30-CE-002 30-CE-003

0.07 mm/year

Tag – WL Coupons Unit May 1994 June 1999 June 2001 June

2001a

30-CE-1001 mm/year 0.00 0.002

30-CE-1002 mm/year 0.00 0.002 0.001

30-CE-1003 mm/year 0.00 0.001 0.003 0.01

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