Cdr. Balakrishnan G Nair (IN Retd)

Present Affiliation

Saipem India Projects Private Limited

Academic Qualification

B.Tech (Naval Architecture), Cochin University of Science & Technology, 1983 - 87PG (Naval Construction), IIT Delhi, New Delhi, 1988 -90PGDBA (Operation Management), Symbiosis, Pune, 2005- 07

Area of Specialization

Naval Architecture, Warship Design, Steel Structures, Structural Fabrication, Survey, Project Management.

Achievements/Awards

Admiral Bharat Bhushan Award for best Ship Design project at IIT Delhi, 1990Commendation by Commander-in-Chief, Southern Naval Command, 1997‘Certified Value Engineer’, 1998Commendation by Chief of the Naval Staff, 1999'Operation Vijay' Medal for significant technical contribution to Indian Navy, 2000Member, Indo-Russian team for Technical Acceptance of BrahMos Missile Launcher, 2004‘Six-Sigma – Green Belt’, 2010Associate Member, The Royal Institution of Naval Architects, London, 2012

Paper Title Asset Integrity Management of offshore platforms and associated issues & challenges

Photograph of speaker

ASSET INTEGRITY MANAGEMENT OF OFFSHORE PLATFORMS,

ASSOCIATED ISSUES & CHALLENGES

Cdr Balakrishnan G Nair, (IN Retd),Chief Engineer, Saipem India Projects Private Limited

CONTENTSCONTENTS

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1.1. ABOUT SAIPEMABOUT SAIPEM2.2. BACKGROUNDBACKGROUND3.3. CASE STUDYCASE STUDY4.4. DESIGN LIFE & LIFE EXTENSIONDESIGN LIFE & LIFE EXTENSION5.5. EFFICACY OF ASSET INTEGRITY MANAGEMENT EFFICACY OF ASSET INTEGRITY MANAGEMENT 6.6. TOOLSTOOLS7.7. ISSUES & CHALLENGESISSUES & CHALLENGES8.8. WAY AHEADWAY AHEAD9.9. REFERENCESREFERENCES

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ABOUT SAIPEMABOUT SAIPEM

ABOUT SAIPEMABOUT SAIPEM

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Operating in more than 60 countries

> 50,000 employees from >130 nationalities

11 fabrication yards in 5 continents 29 engineering and project execution

offices worldwide Revenues

– 2014 ~13 B€ Backlog

– June 2014 24.2 B€

Saipem A Major Multicultural E&C & Drilling Contractor

ABOUT SAIPEMABOUT SAIPEM

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A Leading Global EP(I)C General Contractor

ABOUT SAIPEMABOUT SAIPEM

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An impressive track record over more than 60 years

ABOUT SAIPEMABOUT SAIPEM

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Global Presence with a Multilocal Emphasis

ABOUT SAIPEMABOUT SAIPEM

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Global Presence with a Multilocal Emphasis

ABOUT SAIPEMABOUT SAIPEM

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Saipem Businesses and BUs

ABOUT SAIPEMABOUT SAIPEM

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Saipem E&C: Complete Range of EPC/EPIC Services

ABOUT SAIPEMABOUT SAIPEM

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Saipem’s Assets: Major Engineering Centres

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BACKGROUND BACKGROUND TO ASSET INTEGRITY MANAGEMENTTO ASSET INTEGRITY MANAGEMENT

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BACKGROUNDBACKGROUND

- During the Life Cycle of an Offshore Asset, its Integrity can come into question any time.

- Many offshore installations the world over are reaching or being in excess of their original anticipated design life.

- While ageing of systems can affect performance, ageing of the supporting structure can have very significant effects.

- The need to assess integrity of offshore assets particularly when they are nearing their design life requires no emphasis.

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BACKGROUNDBACKGROUND

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BACKGROUNDBACKGROUND

- When an offshore asset reaches its design life, often there is demand that it be continued to be deployed:- To produce oil/gas either from the original fields or- To serve as base for neighboring wells.

- Such assets are likely to remain operational for a significant period of time in foreseeable future.

- Demonstration of structural integrity beyond its design life is a must, as ageing affects performance.

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BACKGROUNDBACKGROUND

Structural performance during life extension

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BACKGROUNDBACKGROUND

- Fig shows variations of deterioration of structural integrity with time.

- The key issue for ageing installations is the increased uncertainty associated with their performance in the later stages.

- Changes in ownership and cycles of contracting out structural maintenance activities may contribute to loss of corporate knowledge.

- Similarly, the change from Certification to Verification may also contribute to loss of corporate knowledge.

- This body of knowledge encompasses Design Criteria, the history of inspection and repair etc.

- In turn, this impacts understanding of current condition of structure.

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BACKGROUNDBACKGROUND- Presence of fabrication defects is of relevance in

ageing installations.- This is particularly so, as they turn significant

under sustained harsh environment.- The changes in the following are additional factors

that need to be considered:- Inspection approaches (detailed to global)- Codes of practice- Environmental criteria

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CASE STUDY CASE STUDY

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ALEXANDER L. KIELLANDALEXANDER L. KIELLAND

Edda 2/7C and Alexander L. Kielland (right)

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- The rig Alexander L. Kielland was built as a mobile drilling unit at a French shipyard and delivered to Stavanger Drilling in July 1976.

- The floating drill rig was not used for drilling purposes but served as a

semi-submersible 'flotel' providing living quarters for offshore workers.

- In 1980 the platform was working in the Norwegian north sea providing offshore accommodation for production platform Edda 2/7C.

- In the evening of 27th Mar 80, > 200 men were off duty in the accommodation onboard Alexander L. Kielland.

- The wind was gusting to 40 knots with waves up to 12 m high. The rig had just been winched away from the Edda production platform.

- Disaster struck and of the 212 people aboard 123 were killed, making it one of the worst disaster in Norwegian offshore history since WWII.

ALEXANDER L. KIELLANDALEXANDER L. KIELLAND

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SEQUENCE OF EVENTS THAT UNFOLDEDSEQUENCE OF EVENTS THAT UNFOLDED

- Around 18:30 those on board the rig felt a 'sharp crack' followed by 'some kind of trembling'.

- Suddenly the rig heeled over 30° but stabilized.

- Five of the six anchor cables had broken, the one remaining cable preventing the rig from capsizing.

- The list kept increasing, at 18.53 the remaining anchor cable snapped.

- The rig turned turtle taking down 123 onboard.

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In March 1981, the Investigation Report brought out the following:-The rig collapsed owing to a fatigue crack in one of its six bracings (bracing D-6), which connected the collapsed D-leg to the rest of the rig.

-The crack was traced to a small 6mm fillet weld which joined a non-load-bearing flange plate to this D-6 bracing.

-This flange plate held a sonar device used during drilling operations.

FINDINGS OF THE INVESTIGATIONFINDINGS OF THE INVESTIGATION

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FINDINGS OF THE INVESTIGATIONFINDINGS OF THE INVESTIGATION

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- The poor profile of the fillet weld contributed to a reduction in its fatigue strength.

- There were considerable amounts of lamellar tearing in the flange plate and cold cracks in the butt weld.

- Cold cracks in the welds, higher stress concentrations due to the weakened flange.

- Cyclic stresses, common in the North Sea.

- All the above played a collective role in the collapse.

FINDINGS OF THE INVESTIGATIONFINDINGS OF THE INVESTIGATION

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FINDINGS OF THE INVESTIGATIONFINDINGS OF THE INVESTIGATION

Part of the bracing that failed during the accident (On display in the Norwegian Petroleum Museum)

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FINDINGS OF THE INVESTIGATIONFINDINGS OF THE INVESTIGATION

- After initial trigger, structural elements failed in sequence, destabilizing entire structure.

- The design of the rig was ‘flawed’ owing to the absence of structural redundancy.

- Additional accommodation blocks were added to the platform in 1978, so as to accommodate 386 persons!

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DESIGN LIFE & LIFE EXTENSIONDESIGN LIFE & LIFE EXTENSION

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DESIGN LIFE & LIFE EXTENSIONDESIGN LIFE & LIFE EXTENSION

- “Design Life” and “Life Extension” are to be understood clearly particularly in the context of ageing installations.

- The Design Life of an installation is not well defined in codes and standards (See Table in the following slide).

- For the purposes life extension, definitions of Design Life as in ISO-2394 & ISO-19902 are considered appropriate.

- This can be adapted as 'The assumed period for which a structure is to be used for its intended purpose’

- This is ‘with anticipated maintenance but without substantial repair on account of ageing processes'.

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DESIGN LIFE & LIFE EXTENSIONDESIGN LIFE & LIFE EXTENSION

Code, Standard or Guidance Definition of Design Life

ISO 19900, Petroleum and natural gas industries - General requirements for offshore structures

Service requirements - the expected service life shall be specified in design.

ISO 19902 - Fixed steel installationsThe assumed period for which a structure is to be used for its intended purpose with anticipated maintenance but without substantial repair being necessary

NORSOK - N001 Structures shall be designed to withstand the presupposed repetitive (fatigue) actions during the life span of the structure.

HSE Design & Construction Regulations 1996

Reg. 4 - need to ensure integrity of a structure during its life cycle. Processes of degradation and corrosion to be accounted for at the design stage; Reg. 8 - need to maintain integrity of structure during its life cycle.

DnV - Classification Note 30.6, Structural reliability methods

Definition of design life: ‘The time period from commencement of construction to until condemnation of the structure’.

D.En / HSE Guidance NotesCalculated fatigue life should not be less than 20 years, or the required service life if this exceeds 20 years. The (cathodic protection) current to all parts of the structure should be adequate for protection for the duration of the design life.

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EFFICACY OF EFFICACY OF ASSET INTEGRITY MANAGEMENT ASSET INTEGRITY MANAGEMENT

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EFFICACY OF ASSET INTEGRITY MANAGEMENTEFFICACY OF ASSET INTEGRITY MANAGEMENT

- The structural integrity management of ageing installations requires:

* Accurate knowledge of the condition of a structure with respect to fatigue & corrosion;* Understanding of response of the structure in aged condition.

- Appropriate inspection techniques & structural analysis methods are necessary. - It is important to achieve the correct balance between structural analysis and inspection.

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EFFICACY OF ASSET INTEGRITY MANAGEMENTEFFICACY OF ASSET INTEGRITY MANAGEMENT

The successful implementation of a structural integrity management plan also depends on:

-Understanding the degradation processes.

-Availability of appropriate level of data on actual condition of the structure.

-Reliable assessment methods.

-Implementation strategy to deal with increasing risk of failure with time.

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EFFICACY OF ASSET INTEGRITY MANAGEMENTEFFICACY OF ASSET INTEGRITY MANAGEMENT- Asset Integrity Management programs for Oil & Gas

Industry are generally tailored for specific asset.- They take a comprehensive approach towards

managing risk throughout the life of the asset.- It encompasses core elements of an effective risk

management consisting of:

- Integrity Management (structure& equipment)- Configuration Management- Emergency Response.

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A.I.M - WHAT IT ENTAILSA.I.M - WHAT IT ENTAILSIntegrity Management-Should include asset-specific survey planning, suitable software to manage & track asset’s structural condition & program management.

Configuration Management-Must provide industry-proven offshore stability monitoring and load management combined with periodic configuration audits.

Rapid Response Damage Assessment-It should employ customized salvage response plans allowing for rapid evaluation of damaged conditions to an offshore asset in emergency situations.

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TOOLSTOOLS

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TOOLS ENABLING A.I.MTOOLS ENABLING A.I.M- Physical match of facility Vs as-built documentation- Topside Weight Control Reports- Corrosion, Erosion and Thickness Records, Marine growth- A risk evaluation and identification of hazards and failure modes- Prospect of wave-in-deck loading (represented by reserve freeboard ratio)- Report on experiences of adjacent fields and actual field Sea-states- Scour Survey- Seabed subsidence information- Fatigue Strength Assessment- Pushover Analysis & RSR

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ISSUES & CHALLENGESISSUES & CHALLENGES

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ISSUES & CHALLENGESISSUES & CHALLENGES- The subject of ageing installations is of great significance for the offshore industry and will remain so with an ever-increasing population of ageing structures.

- This significance is increasingly reflected in the content of current regulations, codes, standards & RPs.

- They give recognition to the requirement that specific consideration of the ageing process is required.

- Those assets which did not have a well established A.I.M program during their life cycle would be more ill prepared for life extension.

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ISSUES & CHALLENGESISSUES & CHALLENGES- The structural integrity management of ageing offshore installations is a complex process.

-The performance of ageing installations can be highly variable though deterioration can occur at any stage in the life cycle, depending on:

- The design of the structure- Fabrication quality- In-service inspection and repair activities- Quality & extent of structural assessment

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ISSUES & CHALLENGESISSUES & CHALLENGES

- There is the issue of deterioration which is not known, either because of inadequate inspection or because the component is un-inspectable.

- This also requires competency in the wide range of activities essential to the structural integrity management process.

-Operators have tended to treat installations in the life extension phase in the same way as installations operating within their design life.

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ISSUES & CHALLENGESISSUES & CHALLENGESOther technical issues to be addressed are:

-Accelerating local fatigue beyond design limits

-Widespread fatigue damage and subsequent loss of redundancy.

-Maintenance of corrosion protection and allowances.

-Pile integrity, accumulated accidental damage.

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ISSUES & CHALLENGESISSUES & CHALLENGES- Data on the original design criteria, material

properties, fabrication quality and installation performance are required but may not necessarily be available.

- Difficult to obtain a match between as built document and the physical condition.

- Even in cases where original WCR are available, it s unlikely that through life record of weight monitoring data is available onboard

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ISSUES & CHALLENGESISSUES & CHALLENGES- Data on Corrosion, Erosion and Thickness

Records, Marine growth particularly in inaccessible region are difficult to obtain.

- Seabed subsidence data and scour survey may be unavailable/ costly to obtain or practically impossible.

- Unless an effort has been made over a period of time it is unlikely that data on sea-states actually experienced by adjoining platforms are available in discernible manner.

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WAY AHEADWAY AHEAD

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WAY AHEADWAY AHEAD- There is a need for the development and application

of new inspection techniques, e.g. on-line structural monitoring methods.

- This would enable continuous monitoring of the structural integrity of offshore installations during the life extension phase.

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WAY AHEADWAY AHEAD- Through life weight control mechanisms that highlight

significant changes that can affect structural integrity caused by deviation from original design conditions.

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WAY AHEADWAY AHEAD- It is important to take advantage of

inspecting and testing of components from decommissioned structures to establish the effects of ageing.

- This is particularly beneficial for components that are difficult to inspect.

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WAY AHEADWAY AHEAD

- Create an electronic model as close to the current physical status of the platform.

- As and when the situation demands, run a SACS analysis as against the current environment condition.

- Undertake Seismic Analysis if applicable.

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WAY AHEADWAY AHEAD- Carry out a FEM analysis for critical joints.- Perform a Fatigue Analysis based on

knowledge of the cycles the platform was exposed to.

- Perform a Push-over Analysis for ensuring availability of adequate Reserve Strength Ratio (RSR).

- Predict the residual life based on available corrosion margin.

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REFRENCESREFRENCES

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REFERENCESREFERENCES1. Offshore Asset Integrity Management - Program for Life Cycle Maintenance– A publication by ABS Nautical Systems Division

2. Life Extension issues for ageing offshore installations - A. Stacey, M. Birkinshaw, J. V. Sharp - OMAE2008

3. Lifetime extension of ageing fixed offshore platforms and subsea assets AIM Forum, Bureau Veritas – Kuala Lumpur 17-18th September 2013

4. Technical challenges relating to continued safe operation of Ekofisk platform structures arranged, Michael Erik Hall May, 2007

5. Repairing of tubular joints damaged under cyclic loadings: An innovative technique, T S Thandavamoorthy, A R Santhakumar, A G Madhava Rao – 12WCEE, 2000

6. Risk Assessment Method for Offshore Structure Based on Global Sensitivity Analysis, Zou Tao, Li Huajun and Liu Defu, 2012

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REFERENCESREFERENCES7. Surveys using Risk-Based Inspection for The Offshore Industry. ABS, 2003

8. Structural Reliability Applications in Risk-Based Inspection Plans for Semi-Submersible Floating structures, A. Ku, Bernardo Nietmann, V. Krzonkalla , et al, Deep Offshore Technology 2012

9. Risk based fatigue inspection planning – state of the art, Tom Lassen, 5th Fatigue Design Conference, Fatigue Design 2013

10. An extended methodology for Risk based Inspection Planning, J.T Selvik, P. Scarf, T. Aven – Mar 2011

11. Structural Integrity Management- from cradle to grave, Mohammad Nabavian – 2013

12. Asset Integrity Management extends reach, M.F Renard, 2013

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THANK YOUTHANK YOU