2PLANNING THESYSTEMhegasconditioningand processingequipmentisonlya partof theentiresystem.Thetotalsystem maylookverymuchlikethatshowninFigure2.1. For convenience,wedivideeachsystemintoafractionationtowerwithitsmodules. Adehydration unit,forexample,wouldea module!as wouldauxiliaryequipment. Thechoiceof moduleisgovemedyconvenience,othfor calculationanddeci" sion purp#ses.$nfortunately,onecandoasound%oofdesigning,specifyingandoperatingeachmodular unitand yetend upwitha poorsystem. Thereason...eachmodulehasvaryingcharacteristicsunder varyingloadsthatmayresultinatypeofinterna&incompatiility.'nemodularunitmayrequirea certainincoming analysistoproducetheoutputdesired.Ifa previousunit(loesnotmaintainthis,the su%ectunitmaynotprovesatisfactory. Thefaultmightnotl)esomuchwiththatunitutwithtotal system design * even though the unitis usuallylamed+.,ostoftheerrorsoservedinsystemdesignare-errorsofomission.-Thosefacetsofthe prolemreceivingthoughtful,formalconsiderationusuallyarehandledsatisfactorily. Itisthethings wefailtoconsiderproperlythatusuallyareattherootofmostprolems. 'nesuchomissionisto concentrateonthedetaileddesignofeachmodulewithoutproperconsideration ofthetotalsystem withinwhichitresides. Anotherisfailuretoproperlyrecogni.ethedegreeofuncertaintyintheinputGasProcessingC02 and/or SulfurCompression(optional)CompressionNGLsCompression1""""""1/(optional)Gas Salesor ReinjectionProductionSeparationCrudeOil/CondensateStaili!ation and "e#$drationOil %ater&'(((NGL SalesCrude Oil/CondensateSales%aterto disposal.-- Produced%ater(s(e(a(or(r(ei))*nj*)e(ct(io))*n) +++&reatingFigure 2.1 Sc#ematic ,ie- of a &$picallntegratedProduction.acilit$CHAPTER 2 23-1.iCHAPTER 2 2020 VOLUME1: THEBASICPRINCIPLESPLANNINGTHESYSTEMandoutputspecificationsof thesystem. 1et anotheris toignorethechangeinthemoduleinputsover thelife of thefacility.Theprocess ofsimulationisnothingmorethanperfarming *inadvance+thosecalculationswhichcharacteri.esystemehavior. Themostroutineformofsimulationsimplyinvolvessolvingtheequationswhich*hopefully+descrietheoperationofconcem. Althoughwecurrentlydomuchof thisonacomputer,nothingisaddedtotheresultunlessgreatertrueprecisionisotained. 2e maysimplyotainmorenumersinagivenperiodoftime. Thisinitselfisgoodfarmorealtemativesmayeconsidered. 3ut... wemustrememerthatetterdesignisnotanautomaticresultofthesimulationexercise.Total simulationmustformallyrecogni.etheuncertainty*risk+ofthenumersused.$singanaverageormostproaleanalysisisnotananswer.Theseareonlytwopointsonthelikelydistriu"tioncurve*meanand moderespectively+. Total simulationmustincludetheseconcemsso thatthesys"temmay possessnecessaryflexiility*overits life+ with m)nimum useof aritrarysafety factors.'viously,goodsamplesarenecessary.AppendixAconsiderssamplingproceduresnecessarytootain relialedata.THEBASICSYSTEMFigure2.1 representsafairlycompleteprocessingsetupfarhandlingproducedfluids.Iten"compassesalmostallsystemsused.4otallelementsshownarecurrentlyorpotentiallypresentinagivensystem. Thepurposeistoshowmostofthecommonaltematives.Thetimelagetweenorigi"nalreservoirplanningandtheultimatedispositionofits-goods-*possilymanyyearshence+requiressorne initialconcemfarultimatepotential.5achofthesquaresshown representsacalculationmodule. 2ithinthismodulethereisa odyofequationsand practicewhichenalesonetodesignit" su%ecttotheimposedconstraints.Tradi"tionally,ad%ectiveshaveeenusedinfrontof theword-engineer-tolooselydefinethemodularareas"chemical,petroleum,mechanical,etc.Asthesystemshaveecomemorecomplex,calculations withina modulecan neverrealisticallyexclude theother modules.4otshowninthemodularsetuparethe pumps,compressors,valvesandfittings,andlinesnec"essary to move,controland containthe fluidsflowing etweenmodules.6orne ma%armodulesshownhaveanumerofsu"modulesrepresentingcomponentpartsthatinvolvesorneunique and7orseparateengineeringconcem. Far example,withinthegasprocessingmodulethe489extractionmodulecouldesudividedasshowninFigure2.2. Thisfigureisfartheverysimplestformof refrigerationsystemconsistingofinlet7productexchange,refrigeration,andsepa"rationof liquid from vapor.Thefactthatalloftheoperationsdonotoccurat,orinthevioinityof,theactualproductionsiteproducingoperation(loes notchangetheasicsystemoritsneeds.Theveryseparationofthefunctionsinvolved" resultingfromorgani.ationalandgeographicalconsiderations" dictatestheneedfaranoverallplanningfunction. 6uperimposingthisnecessaryfunctionontopofspecificfunc"tions... whichhaveeenatleastsemi"autonomous... isnoeasytask. 'nonehand,theplannerdoesnotalwayspossessthetechnologicalexpertisetoimposerealisticconstraintsoneachindividualele"mentinthesystem.'ntheotherhand,thepeoplechargedwithoperatingeachelementresistchangefromthosepracticeswhichhaveservedthemwell"traditionally.Too oftenthechargeseeminglyre"duces to,-:educecost,-whenwhatis meantis, -;ncreaseprofit.-fCHAPTER 2 2?rofitwillresultfromdecreasingcostifallotherfactorsremain thesame. $nfortunately,overemphasis oncostusually changes otherfactors.@andlingthesystemas asystem "insteadofaseriesoflooselyconnectedindividual functions"canleadtoa more rational asisforgreater net profit.Constraintsof theBasic SystemThesystem hassevera&asicconstraints=1.The quantityand analysisof fluidsentering2. The marketdemand *quantityand price+for theeffluent productsA. 9egalandquasi"legalconditionsimposed" -no"flare-gasorders,proration,con" tractsandagreements,nationaland politicalconcems,etc.0. ?hysicalenvironmentalfactors"laoravailaility andquality,climate,localcus" toms, populationdensity,availailityof utilitiesandservices,etc.