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Hotel Safety BriefingSafety MomentIcebreaker Super Secret BingoMaterials SelectionBreakCorrosion ControlExerciseWrap UpAgenda

Safety Moment Clear LabellingIcebreaker Super Secret Bingo

1Upstream Oil & Gas

Materials Selection & Corrosion Control

Picture what is the cause: Materials Selection or Corrosion ControlLinkage between the two: once the material is selected it has to be protected2What is the goal of Materials Selection?

Question to the participants get some discussion going3 RISK

Event: LOSS OF CONTAINMENT(API RP 754 Loss of primary containment LOPC)

Risk = Probability * ConsequenceMaterials Selection & Corrosion Control is part of risk managementRBI is a validation of the materials selectionConsequence cant really be changedFocus on probability (likelihood)4Process Safety is a disciplined framework for managing the integrity of hazardous operating systems and processes by applying good design principles, engineering and operating practices. It deals with the prevention and control of incidents that have the potential to release hazardous materials or energy. Such incidents can cause toxic effects, fire or explosion and could ultimately result in serious injuries, property damage, lost production and environmental impact.(2007, CCPS with BP additions in blue)

Process Safety BP Definition

Important to point out that it is not only hydrocarbon that can be dangerous5UK North Sea Pipeline Loss Of Containment

We can get an idea from loss of containment data from LOC statistics (Oil & Gas UK database)Pipeline and Riser Loss Of ContainmentData is up to year 2000Corrosion is 6Risk Assessment Matrix

Generic Shell matrix from 2001Each Company will have their own matrixRelate the release statistics to the likelihood columnQualitative versus QuantitativeOGP has a very good suite of Quantitative Risk documentsPEAR mnemonicPeople = HSE Assets = Financial7Elements of an Integrity Management System

John Reynolds Inspectioneering.comPEI = Pressure Equipment IntegrityDeterioration Management; Codes Standards Regulations; Risk Assessment & Inspection Planning8UKOOA Risk Based Decision Making

Easy decisions at the top; difficult at the bottomEasiest with standards, but are standards always right for every situation? Then we move to BHow far do we want to go with Materials Selection?Do we really want to get into QRA to select materials?Remember Company values can already be incorporated into internal standards. Deviation goes against Company values9

International, Regional & National Standards

Explain hierarchy of standardsISO 21457 evolved from M-00115156 only for cracking doesnt deal with weight loss corrosionDo not forget non-metallics they can leak too O-rings important10Company Standards

What about Oxy and WGCCC?11Options

Part of NORSOK M-001, Table 3http://www.standard.no/PageFiles/1194/M-001.pdf

Not a comprehensive listing. Just to show that each application could have several choices of materials.What defines low corrosivity?So, how do we work these options into a definitive materials selection?12Inputs to Materials Selection Process

Gives an idea of the large number of elements that the materials & corrosion engineer needs to be involved withOperations philosophy because the operating requirements, particularly inspection, will help finalise the choiceSupplier experience and qualification can the selected materials be manufactured and supplied reliably?13

http://www.hse.gov.uk/research/rrhtm/rr672.htm

Some key questions asked by UK HSE14What material do we start with?When there are no given options, or when the options allow

start with CARBON STEEL

Prove that it works15Degradation Mechanisms

Materials will degrade, even CRAs, so we need to evaluate whether they will meet lifetime requirements and whether they may be subject to non-age related degradation.Although API is for refinery, the majority of mechanisms are common to upstream as well.We need to make a call about the extent of failure in deriving consequences is it leak or break?16

17CO2 CorrosionMost common internal corrosion mechanismCO2 dissolves in water to give carbonic acidPitting; Mesa; Flow induced localised corrosion (FILC) (usually laboratory only)Top of line corrosion (TOLC)Key factors: water chemistry, pH, hydrocarbon type, water content, CO2 partial pressure, H2S partial pressure, organic acids, temperature, steel chemistry, fluid dynamicsResults in either leak or rupture

Usual starting point with carbon steelProduces three corrosion morphologies18CO2 CorrosionPittingMesa

Pits can join up to form a groove which then bursts for a rupture1914+ different modelsLab basis; Field basis; TheoreticalLaboratoryDe Waard-Milliams, Shell Hydrocor, NORSOK M-506, Intetech ECE, Honeywell PredictFieldTotal CorplusTheoreticalOhio U Multicorp, BP CO2, U Tulsa SSPS CO2CO2 Corrosion Modelling

Which models are the participants familiar with?20CO2 Corrosion Modelling

http://www.ife.no/en/publications/2009/matkor/prediction

A useful guide to apply to corrosion modelling work21CO2 Corrosion ModellingDetermine order of magnitude uninhibited corrosion rateAssessment of carbon steel service lifeEstimate a corrosion allowance for carbon steelImplications for corrosion control by inhibitionWhat about pitting?Does carbon steel give an acceptable risk, or is another material required?

Models are NOT accurate to decimal placesAssessment of service life requires good production profile data focusing on key parameters that affect CO2 corrosionIs corrosion rate so high that inhibition still leaves a high risk in terms of availability requirements and performance BP model in NACE 2011, Paper 11062 - INHIBITOR LIKELIHOOD SUCCESS SCORE ILSSILSS = (Temp deg C/40) + (Shear Stress Pa/240) + (TDS ppm/125,000) + (Predicted Corrosion Rate/10)ILSS < 2.5 High likelihood of successful inhibition; ILSS > 5.5 High likelihood that inhibition will not be satisfactory even at high doseThis highlights link between Materials Selection & Corrosion Control22Sour weight loss corrosion

Sulphide stress cracking (SSC)

Hydrogen induced cracking (HIC)

Stress oriented hydrogen induced cracking (SOHIC)

H2S Corrosion & Cracking

23ISO 15156-1:Exposure to oilfield environments that contain sufficient H2S to cause cracking of materials by the mechanisms addressedHIC is now included and has no lower limit of H2SBy definition, any amount of H2S above zero ppm constitutes a sour environment Sour Service

24C

Can reduce CO2 corrosion rate by sulphide film formationPitting at film breakdown pointsPredictive modelling very difficultUse of CO2 models conservative, or not?Most likely results in a leakSour weight loss corrosion

Note that oxygen is the worst corrodent25Carbon steel SSC regions of environmental severity

No minimum H2S level for CRAsSSC

26Majority rely on ISO 15156 requirements for environment, heat treatment, hardness, cold work etcSome users have developed their own limits which can be more, or less, restrictiveFailures difficult to predict and monitor and can be catastrophic ruptureSSC

27Establishment of biofilms can create a corrosive micro environment, or enhance other ongoing mechanismsInternal and External problemFactors (internal):Separated water; 5< pH