Integrity Management of Submarine Pipeline
Systems
B.H.Leinum, Det Norske Veritas
PSA Stavanger 9 December 2009
Presentation - Content
ƒ Introduction to DNV RP-F116 on Integrity Management of Submarine
Pipeline System
ƒ Examples from the IM-process for the Siri Infield-Pipelines in Danish
Sector (Dong Energy)
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2
DNV RP-F116; Motivation & State-of -Affair
ƒ
Motivation:
- Feedback from industry
- Aging pipeline systems
- Life time extension and re-qualification of existing pipelines
- Optimised design imply stricter need for monitoring
- Novel design gives new challenges
ƒ
State-of-affair
As pr. today, there are no recognized specifications or recommended
practices available covering subsea integrity management systems
ƒ
-
API1160 “Managing System Integrity for Hazardous Liquid Pipelines”
-
ASME B31.8S “Managing System Integrity of Gas Pipelines”
Objective:
- Address in-service issues of concern from early design
phase and through the operational phase
- Compile best industry practice and sound engineering
practice for how to establish and maintain the integrity
of subsea pipeline systems
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Onshore Codes
Recommended practice for IM of Submarine Pipeline Systems
ƒ JIP Participants ) shows international co-operation;
ƒ CNOOC
ƒ DONG Energy
ƒ ENI Group
ƒ Gassco
ƒ Gaz de France
ƒ Statoil
ƒ SINTEF
ƒ Norske Shell
ƒ DNV
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What is Pipeline System Integrity?
The function of pipeline systems is to efficiently and safely transport a
variety of fluids
„ Pipeline
system integrity is defined as the pipeline system’s
structural/containment function. It is the submarine pipeline system’s
ability to operate safely and withstand the loads imposed during the
pipeline lifecycle. If a system loses this ability, a failure has occurred.
ƒ There are two main failure modes related to the pipeline’s
containment / structural function:
- Loss of containment – leakage or full bore
rupture.
- Gross deformation of the pipe cross section resulting
in either reduced static strength or fatigue strength.
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5
The Integrity Management (IM) System
The Core
Surrounding
Facility Systems
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Integrity Management (IM) Process
IM-Process in a life cycle perspective:
Pipeline integrity is
ƒ Established during the concept, design
and construction phases.
ƒ Maintained in the operations phase.
ƒ Transferred from the development
phase to the operations phase. This
interface involves transfer of vital data
and information about the system.
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Threat group versus failure statistics
•
DFI threats
–
–
–
–
–
•
•
•
•
•
Material
10 %
Impact
24 %
Other
11 %
→ Structural
Anchor
18 %
→ Natural Hazard
Extreme whether
Earthquake
Landslide
Ice loads
Incorrect operation
–
–
–
→ Impact & Anchor
Global buckling – exposed line
Global buckling – buried line
End expansion
On bottom stability
Static overload
Fatigue
Natural hazard threats
–
–
–
–
→ Corrosion
Trawl interference
Anchoring
Vessel impact
Dropped objects
Structural threats
–
–
–
–
–
–
Structural
5%
Internal corrosion
External corrosion
Erosion
3rd party threats
–
–
–
–
Corrosion
27 %
Material related
Manufacturing related
Fabrication related
Installation related
Design errors
Corrosion/erosion
–
–
–
→ Material
→ Other +
The North Sea*
All reported
incidents, both
leakage and not
leakage
* Fittings are not included
Incorrect procedures
Procedures not implemented
Human errors
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Nat. Hazard
5%
8
8
Risk Assessment & Integrity Mangment Planning
A) Equipment scope
Risk assessment and IM Planning – main tasks
and link to code requirements (DNV-OS-F101):
B) Identify threats
C) Data gathering
ƒ Define equipment scope ( i.e. all equipment that
can lead to a failure)
D) Data quality review
No
Yes
F) Estimate CoF
ƒ For each equipment, identify all threats which
can lead to a failure
Data OK?
E) Estimate PoF
H) Mitigation
ƒ For each threat; estimate risk
- Consequence of failure (CoF)
- Probability of failure (PoF)
G) Risk = PoF x CoF
No
No
Yes
Risk OK
No
I) All equip./threats
considered?
ƒ Propose plans for:
- Inspection, monitoring and testing (IMT)
- Mitigation, intervention and repair (MIR)
- Integrity assessment (IA)
Yes
J) Aggregated risk
Risk OK
Yes
K) IM Planning
No
Risk assessment – working
process
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Example: The Danish Oil and Natural Gas system – Siri Field
Siri
Nini
Umbilical
m
32 k
Cecilie
10" Water injection
13
4" Gas lift
km
m
9k
Oil Storage tank
SAL
System
14" Multiphase
Stine S1
Production SCB-1
SCB-2 Water injection
16" Oil
10" Water injection
3” Gas lift
8” Multiphase
4" Gas lift
12" Multiphase
The Siri-Nini-Cecilie-Stine Field
Location
Type of
Pipeline
1
Nini - Siri
MP
14”
31.7
2
Nini - Siri
WI
10”
31.7
3
Nini - Siri
GL
4”
31.7
4
Cecilie - Siri
MP
12”
12.9
Cleaning & ILI
2003
5
Cecilie - Siri
WI
10”
12.9
Cleaning & ILI
2003
6
Cecilie - Siri
GL
4”
12.9
7
Stine 1 - Siri
MP
8”
8.9
Emergency
2003
8
Stine 1 - Siri
GL
3”
8.9
Emergency
2003
9
Siri/Nini - SCB2
WI
6”
None
2003
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Size
Length [km]
Pigging Facilities
Inst.
year
Design life,
years
Cleaning & ILI
2003
15
Cleaning & ILI
2003
2003
2003
10
15
Notes
Piggy-back
15
15
Piggy-back
12
Piggy-back
12
10”x6” tee spool
Risk based approach; Basis for the inspection plan
1. Identification of threats
¾ Major threats; Third Party interference (impact) and
Corrosion (internal/external).
2. Risk Assessment
3. Identification of regulatory requirement
4. Selection of inspection methods (how)
5. Inspection scheduling (where, when and what)
6. Integrity Assessment
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Example of a Risk assessment scheme
Threat identification; date gathering and design review
Threat Group
DFI
Corrosion /
Erosion
Third Party
Structural
Natural
Hazard
Incorrect
Operation
Threat
Potential
Initiator
Pipeline
Sections
Protective means
(DFI)
Initial risk assessment
Acceptance
Criteria
Design errors
Fabrication defects
Installation related
Internal corrosion
External corrosion
Erosion
Trawling interference
Anchoring
Vessel impact
Dropped objects
Vandalism / terrorism
Other mechanical impact
Global buckling – exposed
Global buckling – buried
End expansion
On-bottom stability
Static overload
Fatigue
Extreme weather
Earthquakes
Landslides
Ice loads
Significant temperature variations
Floods
Lightning
Incorrect procedures
Procedures not implemented
Human errors
Internal Protection System Related
Interface component related
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PoF
Category
CoF
Category
Risk
Category
Additional
protective means
Inspection planning
IMT Activities
IMT frequency
Normally covered through QA/QC during
DFI
Normally covered by monitoring activities
and after "unplanned event" inspection
(not part of the long term inspection
program)
Normally covered by other supporting
elements (e.g. audits and review, i.e.
operating in compliance with operatinal
controls and procedures)
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Internal threat screening - corrosion
ƒ All pipelines were screened and categorised for risk of internal corrosion
ƒ Following definitions were used:
-
Insignificant
Moderate
Significant
Severe
–
–
–
–
Condition assessed as better than design
According to Design
Corrosion allowance consumed before end design life
Corrosion allowance consumed before end design life or
non-quantifiable corrosion rate
ƒ Expected development was predicted using NORSOK M-506 for determing
corrosion rates.
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Integrity Assessment: Pipeline burst capacity calculation
ƒ Based on DNV RP-F101, "Single defect" methodology.
ƒ From in-line inspection performed by Ultra Sonic pig (10" WI Riser showed on figure).
Detailed inspection data - Allowable measured defect size for
247bar
1.0
Relative defect depth (d/t)
Allow able def ect size
Features
0.8
0.6
0.4
0.2
0.0
0
100
200
300
400
500
Defect length (mm)
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600
700
800
Requirement for internal monitoring and control programme
ƒ Suggested programme for WI-lines
Monitoring parameter
Schedule
Seawater
Produced water
Pressure, temperature, flow rate
On-line
X
X
Chemical injections
Continuously
X (scale inhibitor)
X (scale/corrosion inhibitor)
O2-content
On-line
X
NA
CO2, H2S
Regularly
NA
X (in degasser)
Bacteria
Regularly
X
Regularly (in seawater
system)
X
seawater system, process top side Siri and at
Cecilie and Nini WHP, if possible
Residual bactericide at the end of the
pipeline
In connection with
bactericide treatments
X
X
X
(monitor seawater
breakthrough)
X
Injection water chemistry of producers
(especially Ba, Sr, SO42-)
Suspended solids
Regularly
X
X
Residual inhibitor
Regularly
X
(scale inhibitor)
X
(corrosion and scale inhibitor)
Residual scavenger
Regularly
X
(oxygen scavenger)
Residual chlorine
Regularly
X
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External threats screening
ƒ Main groups
- DFI – Threats related to design, fabrication and installation
- Third party – Damage to the pipeline caused by third party interference, e.g. anchor or trawl
impact
- Structural – Damage to the pipeline caused by buckling, static over loading, fatigue etc.
ƒ A high level assessment of the Estimate probability of failure (PoF)
ƒ Estimate consequences of failure (CoF)
ƒ Determine risk
- Since the pipelines in question were all buried, most of the threats were screened out. However, there
were two threats that possibly could impact the structural integrity of the pipeline;
- Anchor hooking
- Upheaval buckling
ƒ To evaluate the risk areas of above threats, an identification of previously performed
surveys was needed.
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Integrity Assessment in General (DNV RP-F116)
Overview of damages/anomalies vs. assessment codes
Flow diagram illustrating the different activities the integrity assessment process consists of
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Establishment of a Long Term Inspection plan
ƒ Based on the performed assessment, a 5-year inspection program was proposed.
Siri interfield - Inspection Program 2008-2013
*
*
*
*
AC
2008
ROV
=
Recommended scheduled inspection
Inspection types:
=
Scheduled inspection not performed
=
Inspection performed but no evaluation of results
=
Inspection and evaluation performed
AC: Acoustic Survey, * = entire pipeline
ROV: Rov Inspection, R = Riser(s), PT = Pipe tracker, SA = Selected Areas
ILI: In-Line Inspection
ILI
AC
2009
ROV
ILI
AC
2010
ROV
ILI
AC
2011
ROV
ILI
AC
2012
ROV
ILI
AC
2013
ROV
Nini
Nini-Siri 4" GL pipeline
Nini-Siri 10" WI pipeline
Nini-Siri 14" MP pipeline
*
Pipeline to be replaced
*
*
R+PT
R+SA
R
R+PT
R+PT
R+SA
R+PT
R+SA
R+PT
R+SA
R+PT
R+SA
R+PT
R+SA
R+PT
R+SA
PT
R+SA
*
*
*
R+SA
*
*
*
R+SA
R+SA
R+SA
*
*
*
R+SA
R+SA
R+SA
R+SA
R+SA
R+SA
R+SA
R+SA
*
R+SA
R+SA
R+SA
*
*
*
R+SA
*
*
*
R+SA
*
*
*
R+SA
R+SA
R+SA
Cecilie
Cecilie-Siri 4" GL pipeline
Cecilie-Siri 10" WI pipeline
Cecilie-Siri 12" MP pipeline
*
*
*
*
*
R+SA
R+SA
*
R+SA
R+SA
R+SA
Stine
Stine-Siri 3" GL pipeline
Stine-Siri 8" MF pipeline
6"x10" WI tee-spool
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*
*
*
*
*
*
18
R+SA
R+SA
ILI
SUMMARY
ƒ New RP-F116 gives requirements and recommendations for the
development of a guideline on integrity management system of submarine
pipeline systems from the conceptual design and during operation
ƒ Underlines the importance of transfer of integrity from conceptual/design
phase to the operational phase
ƒ Recommendations related to global buckling, corrosion monitoring
parameters, overview of common pipeline threats,
risk assessment schemes and an example on risk
assessment and IM planning
ƒ Experience has shown that documentation and
structured chart of responsibilities is important
to ensure that the pipeline is operated according
to the premise made in design.
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Safeguarding life, property
and the environment
www.dnv.com
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