Integrity Management of Submarine Pipeline Systems. B.H.Leinum, Det Norske Veritas

Integrity Management of Submarine Pipeline Systems B.H.Leinum, Det Norske Veritas PSA Stavanger 9 December 2009

Presentation - Content Introduction to DNV RP-F116 on Integrity Management of Submarine Pipeline System Examples from the IM-process for the Siri Infield-Pipelines in Danish Sector (Dong Energy) Det Norske Veritas AS. All rights reserved. 2

DNV RP-F116; Motivation & State-of -Affair 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 State-of-affair As pr. today, there are no recognized specifications or recommended practices available covering subsea integrity management systems - 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 Onshore Codes Det Norske Veritas AS. All rights reserved. 3

Recommended practice for IM of Submarine Pipeline Systems JIP Participants shows international co-operation; CNOOC DONG Energy ENI Group Gassco Gaz de France Statoil SINTEF Norske Shell DNV Det Norske Veritas AS. All rights reserved. 4

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. 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. Det Norske Veritas AS. All rights reserved. 5

Integrity Management (IM) Process IM-Process in a life cycle perspective: Pipeline integrity is Established during the concept, design and construction phases. Maintained in the operations phase. Transferred from the development phase to the operations phase. This interface involves transfer of vital data and information about the system. Det Norske Veritas AS. All rights reserved. 7

Threat group versus failure statistics DFI threats Material Material related Manufacturing related Fabrication related Installation related Design errors Corrosion/erosion Corrosion Internal corrosion External corrosion Erosion 3rd party threats Impact & Anchor Trawl interference Anchoring Vessel impact Dropped objects Structural threats Structural Global buckling exposed line Global buckling buried line End expansion On bottom stability Static overload Fatigue Natural hazard threats Natural Hazard Extreme whether Earthquake Landslide Ice loads Incorrect operation Other + Incorrect procedures Procedures not implemented Human errors Impact 24 % Anchor 18 % Corrosion 27 % Structural 5 % Other 11 % Nat. Hazard 5 % The North Sea* All reported incidents, both leakage and not leakage * Fittings are not included Material 10 % Det Norske Veritas AS. All rights reserved. 8 8

Risk Assessment & Integrity Mangment Planning A) Equipment scope B) Identify threats Risk assessment and IM Planning main tasks and link to code requirements (DNV-OS-F101): C) Data gathering D) Data quality review No Define equipment scope ( i.e. all equipment that can lead to a failure) Yes F) Estimate CoF E) Estimate PoF Data OK? H) Mitigation For each equipment, identify all threats which can lead to a failure Yes G) Risk = PoF x CoF Risk OK No No No For each threat; estimate risk - Consequence of failure (CoF) - Probability of failure (PoF) I) All equip./threats considered? Yes J) Aggregated risk Risk OK No Propose plans for: - Inspection, monitoring and testing (IMT) - Mitigation, intervention and repair (MIR) - Integrity assessment (IA) Yes K) IM Planning Risk assessment working process Det Norske Veritas AS. All rights reserved. 9

Example: The Danish Oil and Natural Gas system Siri Field Siri Nini Cecilie Umbilical 32 km 13 km Oil Storage tank 10" Water injection 4" Gas lift 12" Multiphase 9 km SAL System 16" Oil 10" Water injection 4" Gas lift 14" Multiphase Stine S1 Production SCB-1 SCB-2 Water injection 3 Gas lift 8 Multiphase The Siri-Nini-Cecilie-Stine Field Location Type of Pipeline Size Length [km] Pigging Facilities Inst. year Design life, years Notes 1 Nini - Siri MP 14 31.7 Cleaning & ILI 2003 15 2 Nini - Siri WI 10 31.7 Cleaning & ILI 2003 3 Nini - Siri GL 4 31.7 2003 15 Piggy-back 4 Cecilie - Siri MP 12 12.9 Cleaning & ILI 2003 15 5 Cecilie - Siri WI 10 12.9 Cleaning & ILI 2003 6 Cecilie - Siri GL 4 12.9 2003 15 Piggy-back 7 Stine 1 - Siri MP 8 8.9 Emergency 2003 8 Stine 1 - Siri GL 3 8.9 Emergency 2003 12 Piggy-back 9 Siri/Nini - SCB2 WI 6 None 2003 12 10 x6 tee spool Det Norske Veritas AS. All rights reserved. 10

Risk based approach; Basis for the inspection plan 1. Identification of threats 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 Det Norske Veritas AS. All rights reserved. 11

Example of a Risk assessment scheme Threat identification; date gathering and design review Initial risk assessment Inspection planning Threat Group Threat Design errors DFI Fabrication defects Installation related Internal corrosion Corrosion / External corrosion Erosion Erosion Trawling interference Anchoring Vessel impact Third Party Dropped objects Vandalism / terrorism Other mechanical impact Global buckling exposed Global buckling buried End expansion Structural On-bottom stability Static overload Fatigue Extreme weather Earthquakes Landslides Natural Ice loads Hazard Significant temperature variations Floods Lightning Incorrect procedures Procedures not implemented Incorrect Human errors Operation Internal Protection System Related Interface component related Potential Initiator Pipeline Sections Protective means (DFI) Acceptance Criteria PoF Category CoF Category Risk Category Additional protective means 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) Det Norske Veritas AS. All rights reserved. 12

Internal threat screening - corrosion All pipelines were screened and categorised for risk of internal corrosion Following definitions were used: - Insignificant Condition assessed as better than design - Moderate According to Design - Significant Corrosion allowance consumed before end design life - Severe Corrosion allowance consumed before end design life or non-quantifiable corrosion rate Expected development was predicted using NORSOK M-506 for determing corrosion rates. Det Norske Veritas AS. All rights reserved. 13

Integrity Assessment: Pipeline burst capacity calculation Based on DNV RP-F101, "Single defect" methodology. From in-line inspection performed by Ultra Sonic pig (10" WI Riser showed on figure). Relative defect depth (d/t) 1.0 0.8 0.6 0.4 0.2 Detailed inspection data - Allowable measured defect size for 247bar Allow able defect size Features 0.0 0 100 200 300 400 500 600 700 800 Defect length (mm) Det Norske Veritas AS. All rights reserved. 14

Requirement for internal monitoring and control programme 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) O 2 -content On-line X NA CO 2,H 2 S 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 Injection water chemistry of producers (especially Ba, Sr, SO 4 2- ) X (monitor seawater breakthrough) X Suspended solids Regularly X X Residual inhibitor Regularly X (scale inhibitor) Residual scavenger Regularly X (oxygen scavenger) Residual chlorine Regularly X X (corrosion and scale inhibitor) Det Norske Veritas AS. All rights reserved. 15

External threats screening 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. A high level assessment of the Estimate probability of failure (PoF) Estimate consequences of failure (CoF) 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 To evaluate the risk areas of above threats, an identification of previously performed surveys was needed. Det Norske Veritas AS. All rights reserved. 16

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 Det Norske Veritas AS. All rights reserved. 17

Establishment of a Long Term Inspection plan Based on the performed assessment, a 5-year inspection program was proposed. Siri interfield - Inspection Program 2008-2013 * = Recommended scheduled inspection Inspection types: * = Scheduled inspection not performed AC: Acoustic Survey, * = entire pipeline * = Inspection performed but no evaluation of results ROV: Rov Inspection, R = Riser(s), PT = Pipe tracker, SA = Selected Areas * = Inspection and evaluation performed ILI: In-Line Inspection 2008 2009 2010 2011 2012 2013 AC ROV ILI AC ROV ILI AC ROV ILI AC ROV ILI AC ROV ILI AC ROV ILI Nini Nini-Siri 4" GL pipeline * R+PT R+SA * R+SA R+SA * R+SA Nini-Siri 10" WI pipeline Pipeline to be replaced R R+PT * R+SA * R+SA * R+SA Nini-Siri 14" MP pipeline * * R+PT R+SA * R+SA R+SA * R+SA Cecilie Cecilie-Siri 4" GL pipeline * R+PT R+SA * R+SA R+SA * R+SA Cecilie-Siri 10" WI pipeline * * R+PT R+SA * R+SA * R+SA * R+SA Cecilie-Siri 12" MP pipeline * * R+PT R+SA * R+SA R+SA * R+SA Stine Stine-Siri 3" GL pipeline * * R+PT R+SA * R+SA R+SA * R+SA Stine-Siri 8" MF pipeline * * R+PT R+SA * R+SA R+SA * R+SA 6"x10" WI tee-spool * * PT R+SA * R+SA R+SA * R+SA Det Norske Veritas AS. All rights reserved. 18

SUMMARY 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 Underlines the importance of transfer of integrity from conceptual/design phase to the operational phase 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 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. Det Norske Veritas AS. All rights reserved. 19