By Preston Ingalls

RALEIGH,N.C.–Accessdifficultiescanmakeperformingroutineserviceonoilandgasproductionequipmentchallenging,bothasaresultofclose-proximityrestrictionssuchasonaplatform,ordispersionsuchasanonshoreoilfieldwhereequipmentcanbespreadovermanymiles. Amajorobjectiveinmaintenanceoperationsistoensureoperationalcapacitybyreducingunplannedmaintenance.Unplannedmaintenancegenerallycostsfourtofivetimesmorethanplannedmaintenance,soincreasingplannedmaintenancetendstodrivedownthatcost.Insomecases,productionlostasaresultof deferring maintenance can be many times thatmultiplier. Themorecontemporaryandcost-effectiveapproachtopreventivemaintenanceistodoonlywhatisneeded,butnomore.Thisrequiresastrategy. Someinterestingstatisticsbearouttheneedtofocusonthoseactivitiesthatproducethemostvalue,andtodiscardorde-emphasizetherest: •80%ofpreventivemaintenancecostsarespentonactivitieswithafrequency30days or less. •25to30%ofpreventivemaintenanceisconductedatthewrongfrequencies(toooftenornotoftenenough). •30to40%ofpreventivemaintenancecostsarespentonassetswithnegligiblefailureimpact.

FAILURE ANALYSIS Oneofthekeyobjectivestorefiningpreventivemaintenanceprocessistoperformonlymaintenancethatislesscostlythanthefailure.Tohelpwiththis,wesuggestusingafailuremodeandeffectsanalysis(FMEA)orfailuremodeandeffectscriticalityanalysis(FMECA)toexaminetheimpactoffailures.FMECAtakesFMEAtothenextlevelbyincludingacriticalityanalysistodeterminetheprobabilityoffailuremodesagainstthe

severityoftheirconsequences. Thisshouldhelptoidentifyhowdetectableafailureisandhowitcanbespotted.Ifthefailurecanpresentsignificantconsequence,thequestionwouldbe,“Howcanthefailurebedetectedandmitigatedpriortooccurring?” Predictivemaintenancemethodsareconsidered.Whennotavailableorcost-efficient,thenpreventivemaintenancecanbeapplied.Thisshouldincludeoperatormaintenancetasksaswell. FailureModesandcodessuchas

problem,causeandremedycanbeestablishedbystartingwiththoserecommendedinISO14224andAmericanPetroleumInstitute’sRecommendedPractice689.Thoseshouldberefinedwithacarefulexaminationofpastfailures. Figure 1belowshowstherelationshipandsequenceofexaminationstorefinethelevelandtypeofservicetomitigatefailures.ThisillustrationusesSAP(systems,applicationsandproductsindataprocessing)astheenterprisesystem,butanyenterpriseorcomputerizedmaintenance

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Planning Keys Effective Maintenance

The objective is to reduce unplanned maintenance, and increase planned maintenance.

Figure 1

managementsystemcouldwork. Manystartbyfocusingonthemostcriticalequipmentfirst.Onecanidentifymission critical, essential, necessary and supportingequipmentbasedonrisk.Wesuggestrefiningpreventivemaintenanceeffortswherethereisthemostpain.Examiningfailurefrequenciesandtheaccumulationofassociatedcostsandlossescanidentifyculpritsthatneedattention.

DETECTION AND PREVENTION AstheP-FCurvechart(Figure 2) illustrates,failurescanbedetectedinadvancebyconductinganinspection.TheP-FCurveillustratestheactionsofequipmentasitapproachesfailure.Thecurveshowsthatasafailurestarts,theequipmentcomponent(s)deterioratestothepointthatitcanpossiblybedetectedasthe“potentialforfailure”(Ppoint).ThePPointiswherethedegradationcanbedetected. Ifthefailuregoesundetectedandisnotcorrected,itcontinuesonuntilthefailureoccurs(Fpoint).TheFPoint,orfailure,canbelosingfunctionalityorlosingtheability

toperformtospecification(i.e.quality).ThetimebetweenPandF,commonlycalledtheP-Finterval,isthewindowofopportunityduringwhichaninspectionpossiblycandetectthependingfailureandleadtocorrectiveaction. Asthechartillustrates,preventivemaintenanceisoneofthemethodsthathelpsustomigrateawayfromunplannedmaintenance, or emergency maintenance, bydoingmorepreventiveandcondition-basedMaintenance.Theseoftenleadtoresultingcorrectivemaintenance. Morepowerfularethoseproactiveandprecisionactivitiesshownontheleftsideoftheillustration.Manyaresystemicfocuseswhileothersarefocusedaroundensuringreliability.Thesetendtobelessorientedtowarddetectionandmoretowardprevention. Aswemovetotherightfollowingthecurvedownward,weseevariousdetectionmethodologies.Themostaccuratearethepredictivemaintenancetechnologies(severalareshown).Becausepredictivemaintenance–partoftheoverall

condition-basedmonitoringprocess–arelessintrusiveandisbasedmoreonapplyingtechnologiestocompareagainstknownengineeringlimits,ittendstobemoreobjective. Onethenmovestothemostlyvisualprocessofscheduledpreventivemaintenance.Althoughpreventivemaintenancereliesontheinterpretationbythepersonperformingthepreventivemaintenance.Therefore,itismoresubjective.Despitethis,therearestillmanyopportunitiestoapplygoodpreventivemaintenancetechniquestodetectchangesinconditions,sincepreventivemaintenanceincludeslubrication,adjustments,limitedscheduledreplacements,etc.

TAILORING MAINTENANCE PreventiveMaintenanceisatime-basedorinterval-based,plannedservicetodetectandpreventpotentialfailuresandextendthelifeofequipment.Weusemeteredhours,cycles,rotations,andunitsoftimetoscheduleservice.Cyclesofusearefarmoreefficientthantime-basedserviceintervals. Thepurposeofpreventivemaintenanceistominimizebreakdownsandexcessivedepreciation.Initssimplestform,preventivemaintenancecanbecomparedtotheservicescheduleforanautomobileortruck.Itincludesactivitiessuchaslubricating,painting,testing,cleaning,adjusting,andreplacingminorcomponents,aimedatextendingthelifeoftheequipment. Thecostsofoperatingthistypeofprogramarejustifiedbytheresultingdecreaseinequipmentbreakdownsanddelayeddegradationofitsoverallmaterialcondition.Butasstatedpreviously,traditionalpreventivemaintenancebasedonoriginalequipmentmanufacturerrecommendationsisnotalwaysaffordable,mayleadtooverkillintasksandfrequencies. Thatiswhytailoringpreventivemaintenance by identifying probability and

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Figure 2

consequencesmakesmoresense.Focusingonthecomponentswiththegreatestimpactfromfailuresmakesmoresensethanapplyingpreventivemaintenancetaskstopartsandassemblieswithlittleimpactorportabilityofoccurrence. Usingpredictivemaintenanceismorelogicalbecauseitismoreaccurateandlessintrusive,andisabletodetectchangesinconditionearlieronthecurve.Butitisnotalwaysavailableorcosteffective.Westillneedsomedegreeofpreventivemaintenance. Althoughpreventivemaintenancecanincludecleaning,lubricating,testingandscheduledreplacements,themostimportant task is inspection. Inspectionhelpstodetectearlysignsofchangesincondition:awarningofimpendingfailure.Thekeytoinspection

ismakingsuretheequipmentis“tospecification.”Inotherwords,theequipmentanditscomponentsshouldbeinaspecifiedstateorcondition,andtheanomalyofitnotbeingtospecshouldbestated clearly. Tomakethiseffective,preventivemaintenanceproceduresshouldstateclearlyasthe“spec,”whatconditionsoneislookingforornotlookingfor.Forexample,merelysaying“checkbelt”isinadequatebecausethatleavestoomuchtointerpretation.Abetterapproachwouldbetostatetheconditionsonewantstofindthebeltin,suchas“freeofglossing,cracks,fraying,”andtheamountofdeflectionacceptable.

MAINTENANCE TASKS Itisimportanttodeterminewhatpreventivemaintenancetasksareneeded.

Preventivemaintenancefrequenciescanbe altered based on deterioration and failurerates,equipmentavailability,thecostofperformingthemaintenance(labor,materialandlossproduction),andtheconsequencerelatedtoassetfailure. Thekeytoasuccessfulpreventivemaintenanceprogramistocombineitwithoperator inspection. Operator maintenance, calledType1(versusType2formechanicsandtechnicians),isconductedduringsurveillancerounds(dailyandweekly).Type1preventivemaintenancecan detect many potential problems throughsight,sound,touchandsmell.Althoughnotasaccurateasthepredictivemaintenance,itprovidesalast-stopabilitytodetectandcorrectbeforefailurehasoccurred.Operatorscanbetrainedtodetectmanyconditionsastheybegintomanifestthemselvesthroughphysicalcharacteristics. AccordingtooilfieldveteranSherryGregoire, total process coordinator for Holmes Western Oil in Taft California, “Operatorsareclosertotheequipmentthananyoneelse.Theyinherentlyrecognizewhenthingsarenotright.Giventrainingandastructuredoperatorcareprogramusingtotalprocessreliabilityortotalproductivemaintenance,wehaveseenouremergenciesdropdowntothe4-5%range.Operatorsassumemoreownershipandcarefortheequipmentdifferently.” Withthirty-twoyearsintheoilfield,Gregoireispassionateaboutoperatorengagementaspartofthepreventivemaintenance process. Figure 3showspartofanoperatorstandardforaType1preventivemaintenanceonaheatertreater.Noticethesafetyinstruction,specificityanddetailedinstructionsfortheoperatortoconducttheinspection.Pictorialsandcall-outsareusedtoaidtheoperator.Weencourageusingjobaidsandstandardsratherthanrelyingonrecallortextonly.

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Figure 3

Inspection Standard – TYPE 1 Operator

Figure 4aboveshowstheType2preventivemaintenanceonthesameunitfortechnicianstoperformatamonthlyinterval. Over-maintainingequipmentdoesnotleavemuchevidenceofwastedeffort.Infact,weoftenfeelsecureintheknowledgethatwearedoingagreatjobofmaintainingourassetsthroughfrequentpreventivemaintenance.Theproblemis,wearewastingvaluableresources,andinthecasewithmuchpreventivemaintenance,weareshuttingdowntheequipmentunnecessarily.

PERFORMANCE INDICATORS Inrefiningapreventivemaintenanceprogram,thekeyistostartwiththemostproblematicequipment.Italsomeanshavinggoodmetricstomeasuretheeffectivenessandresultsofyourpreventivemaintenanceefforts.Examplemetricsorkeyperformanceindicatorsinclude: •Preventivemaintenanceasapercentageoftotalmaintenancehours; •Percentageofcompliancewithpreventivemaintenanceschedule; •Meantimebetweenfailuresoncriticalequipment; •Percentageofpreventivemaintenancereview(revisedpreventivemaintenance);

•Percentageofcorrectivemaintenancefrompreventivemaintenance;and •Ratioofpreventive-to-correctivemaintenance. Reliableequipmentiscriticaltoeveryoilandgasoperation.Ensuringthatthecorrecttasksaredonewellandontimecanpreventlosses,bothinequipmentandjobdelays. InthewordsofShigeoShingo,“Themostdangerouskindofwasteisthewastewedonotrecognize.”

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Figure 4

Inspection Standard – TYPE 2 Technician

Preston Ingalls, president and CEO ofTBRStrategies,inRaleigh,N.C.Hehasover39yearsofexperienceleadingmaintenanceandreliabilityimprovementeffortsacross27countriesforRoyalDutchShell,OccidentalPetroleum,Hess,KeyEnergy,Bayer,BaxterHealthcare,LockheedMartin,MobilChemical,Unilever,Monsanto,AeraEnergy,Pillsbury,Corning,andTexasInstruments.Forthepast10years,hehasconsultedextensivelywithoilandgas,andhighwayconstructioncompanies.Heholdstwoundergraduatedegreesinengineering,aswellasamaster’sdegreeinorganizationaldevelopment.

If reducing your maintenance costs by 

25‐30% while improving uptime appeals to you, 

call us today.

(919) 341‐1387www.tbr‐strategies.com