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Offshore Losses Case Studies

David BrownBSc(Eng), PhD, CEng, FRINA, FSUT, SNAME, FIMechE

Engineering DirectorBPP Technical Services

OPERA – Lessons from Disaster

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Experience

Author’s Experience

• Professional Naval Architect and Mechanical Engineer

• Chairman of ISSC Floating Structures Committee (from 2000 – 2006)• Committee mandate:

“Concern for the design of floating production systems. Specific emphasis shall be given to FPSO hulls and the recent industry experience that influences the design methodology. Consideration shall be given to identification and quantification of uncertainties for use in reliability methods.”

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BPP’s Background

• Specialist areas include:

• Flexible pipes, risers, umbilicals & cables

• Floating offshore systems

• QA/QC, Installation support

• Risk and failure studies, claims, losses and expert witness

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Contents

Contents

1. Introduction2. Nature of Risk3. Case Studies & Lessons Learned4. Techniques to Predict Failure & Actions

to Mitigate Risk5. Conclusions

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Introduction

Introduction

• Investigations into disasters can prevent them re-occurring in the future

• But lessons learnt can be forgotten

• Investigations into small failures can prevent catastrophic failures

• Total risk can be reduced by minimising the consequence of a failure and/or reducing the occurrence frequency

• Anticipating potential failures at an early stage reduces occurrence frequency

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Introduction

Introduction

An offshore production facility comprises several systems, failures of which can cause injury, halt production, cause damage to the environment and/or result in a total loss of the facility.

Principal Systems

•Platform•Containment•Process•Subsea•Moorings

Initiators of Failure

•Design/Component Selection•Manufacture•Transportation/Installation •Operation•Unexpected Service•Human Factors

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Introduction

Introduction

• A disaster can be categorised as a failure that has severe consequences, this can be:

• Environmental disaster (oil spill etc)

• Financial disaster (downtime, loss of assets etc)

• Human disaster (injury, fatalities etc)

• Combination of all three

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Introduction

The Market Place

• 250% more Floating Production Systems (FPS) than 10 years ago

• As of April 2004 there were 37 production floaters on order• 26 FPSO vessels• 5 spars• 4 production semi-submersibles • 2 TLPs• 5 storage units (FSUs)

• 34 systems will be for W. Africa, with a projected investment of $13 billion by 2010(offshore Magazine Feb 2007)

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Introduction

The Kit

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Introduction

The Kit

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Introduction

High Risk Issues

• Environmental loading at surface and in water-column

• High or low reservoir temperatures

• Corrosive reservoir fluids

• Pressure head from reservoir to surface

• Remote working, distance to sea bed

• Flow assurance

• Mooring and riser system loading

• Fatigue issues – steel catenary risers and steel tube umbilicals

• Offloading

• Complex large crane lifts

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Introduction

Environmental Loading

• Water Pressure - 1 atmosphere for every 10m depth (1 tonne for each metre)

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Introduction

Water Pressure

Depth records broken with time

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Introduction

Remote Working, Distance to Sea Bed

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Introduction

Mooring and Riser System Loading

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Introduction

Mooring and Riser System Loading

Production Risers Systems

(approximate number of risers installed)

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Nature of Risk

Failure and Risk

• Risk is Occurrence Frequency x Consequence• Risk can apply to any, or all, of the following

sectors:

• Human risk (safety)

• Environmental risk • Engineering risk • Financial risk

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Nature of Risk

FPS Risks Compared to Other Engineering Projects

(Sharples, 1989)

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Nature of Risk

Probability of Failure

Quantification of uncertainty is difficult but with careful interpretation it is possible to rank the different sources and their consequence

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Case Study

Case Study – Piper Alpha

• July 1988• Leak of gas condensate• Large explosion• 167 fatalities• Estimated cost $3.5 billion

• Lessons learnt…(Design/Operation)• Offshore Safety Case Regulations (SCR)

implemented• Includes Offshore Installations Prevention of Fire

and Explosion, and Emergency Response Regulations 1995 [PFEER]

• All risks must be shown to be As Low As Reasonably Practicable (ALARP)

• Emergency Shut Down valves (ESD) must be properly positioned

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Case Study

Case Study – Pride of Africa

• November 1999,Pride Africa drill ship lost Blow Out Preventer (BOP) and riser in 5,400ft (1,646m) of water

• Lessons learnt…(Design/Operation)• Wire rope used had a small safety margin• Long length increased the sensitivity to

transient dynamic loads• Wire was also subject to rapid changes in

motor torque

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Case Study

Case Study – Petrobras P-36

• March 2001, Petrobras P-36 sunk in Roncador Field (Brazil) after explosion in supporting columns.

• 11 fatalities and 2190 barrels of oil spilled.

• P-36 was fully insured at approx. USD 500 million

• Lessons learnt…(Design/Operation)• Governing rules and standards may

capture specific systems but can not cover all possible system combinations and events

• Need for risk assessment for non-standard designs

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Case Study

Case Study – Girassol

• Girassol Offloading Buoy Mooring Failure• Spring 2002, buoy broke free of moorings • Chain failed in buoy's hawser, due to fatigue

loading

• Lessons learnt…(Design)• Review of design details• Investigation into behaviour of chain under

tension

(Ref HSE Report: Floating production system -JIP FPS mooring integrity )

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Case Study

Case Study – Petrobras P-34

• October 2002, P-34 was operating in Campos Basin, SE of Brazil

• Power failure caused ballast system valve malfunction

• Rig heeled to 32 degrees• Casualties (no fatalities)

• Lessons learnt…(Design)• Incident caused by inadequate provision of

power to electrical panels and poor programming of valve control system

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Case Study

Case Study – Mumbai High North Platform Fire

• July 2005, Support vessel collides with riser, causing large fire

• 12 fatalities and total loss of platform

• Insured value $173 million

• Lessons learnt…(Design/Operation)• Importance of platform approach corridors• Need for structural protection of risers• Need for Emergency Shutdown Valves

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Case Study

Case Study – Mighty Servant III

• November 2006, during the discharge of her cargo the Mighty Servant III developed a list and sank in 62m of water

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Case Study

Case Study – Flawed Design of a Trans-Atlantic Fibre Optical Cable

• Cable failed after installation• After recovery no fault was found• Cable cross-section analysed using

Finite Element Analysis

• Lessons learnt…(Design)• Hydrostatic pressure caused

distortion of armour wires, resulting in deformation of the core

• Root cause was poor design of armour wire orientation for expected service

• Entire cable was scrapped

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Case Study

Case Study – Failed Pipes

• Failures caused by:• Pipe bird-caging during installation

(Installation)• Sour service conditions (Design)• Poor design (Design)• Extrusion defect (Production)

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Case Study

Case Study – Failed Pipes

• Lessons learnt…• Importance of proper installation

procedures• More attention paid at design

stage• Importance of QA/QC during

manufacture

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Case Study

Case Study –Hurricanes

• API Hurricane Evaluation and Assessment Team (HEAT) set up in 2006 to evaluate all Gulf of Mexico platforms following major hurricanes

• Compare failed platforms with regulations

• Determine whether API Recommended Practices are sufficient

• Suggest changes to Recommend Practices if necessary

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Case Study

Case Study – 2005 Hurricane Season

• One of worst hurricane seasons on record.

• Hurricane Katrina destroyed 44 platforms, damaged 21 others, and damaged 255 pipelines.

• Hurricane Rita destroyed 69 platforms, damaged 32 others, and damaged 206 pipelines.

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Case Study

Case Study – 2005 Hurricane Season

• Lessons learnt…

• API Recommended Practice “Interim Guidance for Gulf of Mexico MODU Mooring Practice – 2006 Hurricane Season” issued to set down new mooring guidelines, including:

• 10 year return period for mooring

• Minimum 1 minute wind speed of 64 knots

• Anchor selection should consider possibility of damage to pipelines

• 2005 hurricane season must be included when preparing site-specific metocean parameters

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Learning

Learning from Incidents

• Results of incident investigations are shared through a variety of means:

• Norwegian FPSO Experience Transfer networkcontains incidents and lessons collected from the operators of five FPSOs in Norway http://www.olf.no/lesson/

• Technical Papers at conferencesEg: OTC, OMAE etc

• Various reports commissioned by UKOOA to spread knowledge among UK operators http://www.ukooa.co.uk/issues/fpso/

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Reducing Risk

Tools to Reduce Risk

• Risk can be reduced by • Lowering occurrence frequency• Minimising consequence of failure

• Achieved by:• Good understanding of expected service conditions

including environment• Comprehensive modelling and testing at design

phase• ‘Policing’ of sub-contractors• Rigorous QA/QC during procurement, production

and transportation phases• Sound operational guidelines and regulations

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Prevention


• Model tests

• Gain better understanding of response to extreme conditions

• Allow for greater understanding of complex interactions

• Used to validate computational analysis

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Prevention


• Finite Element Analysis (FEA)

• FEA can be used to test the design in both extreme load cases and under fatigue

• Potential problems can be highlighted and removed at design stage

• In-service risk is reduced by lowering the occurrence frequency of failure

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Prevention


• Materials tests

• Testing of a prototype allows for validation of computational analysis

• Better to learn from “disasters” that are created in a controlled environment rather than in-service

• In-service risk is reduced by lowering the occurrence frequency of failure

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Prevention


• Monte Carlo Simulations

• Extremely powerful analysis tool –not exploited to the full in engineering

• Applied to claims and loss adjusting it establishes beyond reasonable doubt an appropriate level of repair and associated cost of repair

• Has key advantage that it provides a probability that a specific outcome will be achieved (eg 99% probability that repair cost will be less than $5m)

• Generally accepted method for modelling processes influenced by a large number of individual events that occur randomly in space and time

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Prevention


• Critical Activity Simulation

• Risks and consequences of planned & unplanned events during offshore operations

• Risk can be reduced by lowering the occurrence frequency of disaster or mitigating the consequences

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Prevention


• Good QA/QC policy during manufacture can prevent future disasters.

• Examples of problems during production:• Defects on “approved” wire stock• Extrusion problem

• If not noticed, these problems could have caused catastrophic failures at a later date

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Prevention


• Good QA/QC policy during transportation can prevent future disasters.

• Example of inadequate packing

• If not noticed, this could have caused damage to the riser

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Additional Risks

Exposure to Additional Risks

Due to:• Simplistic extensions of existing technology

• Bringing new technology into use

• Deep water issues

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Additional Risks

Exposure to Additional Risks: Simplistic Extensions of Existing

Technology

• Effects • Underlying cause of many claims in the current

market• Breaks a fundamental ‘design paradigm’ well known

from civil engineering

• Actions for Risk Reduction• Analyse effects with third party analysis or

verification• Account for dynamics, flexibility, pressure loading

etc• Share failure cause information across industry• Just re-think it from the ground up

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Additional Risks

Exposure to Additional Risks: Bringing New Technology into Use

• Effects• The ‘never been done before’ risk factor• Potential economic and risk benefits for the future

• Actions for Risk Reduction• Analyse, test and develop use of new technology

incrementally• Obtain third party verification - MMS Regulations

require a nominated Certified Verification Agent (CVA)

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Additional Risks

Exposure to Additional Risks: Deep Water Issues

• Effects• All cost and time numbers are simply larger• Environmental risks could be greater• Too many ‘single failure event’ induced loss

scenarios exist at present

• Actions for Risk Reduction• Carry out quantified risk analysis• Eliminate ‘single failure event’ loss scenarios with

particular focus on key technologies, such as:• Risers• Umbilicals

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Additional Risks

Risk Management Strategies

• Conduct Technical Quantified Risk Analyses(Make it a warranty on the policy)

• More use of available tools (eg Monte Carlo Simulations)

• Focus on critical components (such as risers/umbilicals)

• Eliminate large ‘single failure event’ induced losses

• Share incident and risk information on an anonymous reporting basis

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Conclusions

Conclusions

• Determining the cause of disasters allows:

• Changes to standards and design practices• Better understanding of failures• Prevention of future disasters

• Disasters can be prevented by:

• Investigating past events• Sharing experience • Thorough modelling and testing at design phase• Consistent QA/QC through procurement/

manufacture• Improved QRA of critical components

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Thank You!

Thank you for your attention!

David Brown [email protected]

Documents

Offshore Losses Case Studies - oilpera.com · Specific emphasis shall be given to FPSO hulls and the ... • But lessons learnt can be forgotten ... Engineering Projects (Sharples,