Offshore Losses Case Studies

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1 Offshore Losses Case Studies David Brown BSc(Eng), PhD, CEng, FRINA, FSUT, SNAME, FIMechE Engineering Director BPP Technical Services OPERA Lessons from Disaster

2 Author s Experience Experience Professional Naval Architect and Mechanical Engineer Chairman of ISSC Floating Structures Committee (from ) 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. 2

3 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 3

4 Contents Contents 1. Introduction 2. Nature of Risk 3. Case Studies & Lessons Learned 4. Techniques to Predict Failure & Actions to Mitigate Risk 5. Conclusions 4

5 Introduction Introduction Investigations into disasters can prevent them reoccurring 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 5

6 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 6

7 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 7

8 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) 8

9 The Kit Introduction 9

10 The Kit Introduction 10

11 Introduction High Risk Issues Environmental loading at surface and in watercolumn 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 11

12 Environmental Loading Introduction Water Pressure - 1 atmosphere for every 10m depth (1 tonne for each metre) 12

13 Water Pressure Introduction Depth records broken with time 13

14 Remote Working, Distance to Sea Bed Introduction 14

15 Mooring and Riser System Loading Introduction 15

16 Mooring and Riser System Loading Introduction Production Risers Systems (approximate number of risers installed) 16

17 Failure and Risk Nature of 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 17

18 Nature of Risk FPS Risks Compared to Other Engineering Projects (Sharples, 1989) 18

19 Probability of Failure Nature of Risk Quantification of uncertainty is difficult but with careful interpretation it is possible to rank the different sources and their consequence 19

20 Case Study Piper Alpha Case Study 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 20

21 Case Study Pride of Africa Case Study 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 21

22 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 nonstandard designs 22

23 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 ) 23

24 Case Study Petrobras P-34 Case Study 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 24

25 Case Study Mumbai High North Platform Fire Case Study 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 25

26 Case Study Mighty Servant III Case Study November 2006, during the discharge of her cargo the Mighty Servant III developed a list and sank in 62m of water 26

Lessons learnt (Design) Hydrostatic pressure caused distortion of armour wires, resulting in deformation

27 Case Study Flawed Design of a Trans-Atlantic Fibre Optical Cable Case Study 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 27

28 Case Study Failed Pipes Case Study Failures caused by: Pipe bird-caging during installation (Installation) Sour service conditions (Design) Poor design (Design) Extrusion defect (Production) 28

29 Case Study Failed Pipes Case Study Lessons learnt Importance of proper installation procedures More attention paid at design stage Importance of QA/QC during manufacture 29

30 Case Study Hurricanes Case Study 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 30

31 Case Study 2005 Hurricane Season Case Study 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. 31

32 Case Study 2005 Hurricane Season Case Study 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 32

33 Learning from Incidents Learning Results of incident investigations are shared through a variety of means: Norwegian FPSO Experience Transfer network contains incidents and lessons collected from the operators of five FPSOs in Norway Technical Papers at conferences Eg: OTC, OMAE etc Various reports commissioned by UKOOA to spread knowledge among UK operators /issues/fpso/ 33

34 Tools to Reduce Risk Reducing 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 34

35 Tools to Reduce Risk Prevention Model tests Gain better understanding of response to extreme conditions Allow for greater understanding of complex interactions Used to validate computational analysis 35

36 Tools to Reduce Risk 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 36

Tools to Reduce Risk Prevention Materials tests Testing of a prototype allows for validation of computational analysis Better to learn from

37 Tools to Reduce Risk 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 37

Prevention Tools to Reduce Risk Monte Carlo Simulations Extremely powerful analysis tool not exploited to the full in engineering Applied to claims and loss adjusting it establishes beyond reasonable

38 Prevention Tools to Reduce Risk 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 38

39 Tools to Reduce Risk 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 39

Examples of problems during production: Defects on approved wire

40 Tools to Reduce Risk 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 40

41 Tools to Reduce Risk 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 41

42 Exposure to Additional Risks Additional Risks Due to: Simplistic extensions of existing technology Bringing new technology into use Deep water issues 42

43 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 43

44 Exposure to Additional Risks: Bringing New Technology into Use Additional Risks 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) 44

45 Exposure to Additional Risks: Deep Water Issues Additional Risks 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 45

46 Risk Management Strategies Additional Risks 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 46

47 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 47

48 Thank You! Thank you for your attention! David Brown 48

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