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1、CHAPTERDeepwaterMetoceanEnvironmentsDEEPWATERMETOCEANENVIRONMENTSMetoceanIntroductionRecentoffshoreoperationa1.disastershavegeneratedagreaterawarenesstooffshoremet-ocean,environmenta1.,safety;andmarinepreservationwithinthezzB1.ueP1.anetofEarth.Withsuchresponsibi1.ityunavoidab1.edutiesmustbeassuredby
2、governments,regu1.ators,agencies,operators,and/oranyvestedbodiesinvo1.vedinoffshoreoi1.andgasexp1.oitation.Concernsraisedfromrecenteventsshou1.dfurtherdemandthatanyindustryengagedinourseasoroceanstakesafarmoreresponsib1.eandaccountedro1.eregardingtheenvironmenta1.andassociatedstandards,metrics,andco
3、ntro1.sneededtopo1.iceandmitigatepotentia1.maritimeorenvironmenta1.damagethatcanresu1.t.Furthermore,munities,sea1.ife,seabedco1.onies,shipping,fishing,mi1.itary/nava1.operations,oranyothermaritimeoroffshoreactivitywheretheenvironmentcanpotentia1.1.ybeharmed.Eva1.uatingMetoceanConditionsMeteoro1.ogic
4、a1.conditionsinthischapterpertaintocombinedeffectsofa1.1.subjectmattersregardingdeepwaterregiona1.orwe1.1.operationsthatresu1.twithinspecificoperatingperiods.Thep1.annedacquisitionofmetoceaninformationisrequiredtoassessandaddresstheissuessothattheevidenceprovidedcanpotentia1.1.yrea1.izeprojectcostsa
5、vings,reduceassociatedoperationa1.risk,andprovidesafetymanagementbenefitsthroughthep1.anned1.ifecyc1.eofoffshorewe1.1.activities.Ametoceanunderstandingisneededtobeapp1.iedthroughprojectp1.anning,design,construction,engineering,andthensafe1.ymanagedandcontro1.1.ed.Aponentpartsarere1.iantonaccurate,pr
6、ecise,and1.ongstandingmetoceandatacriteria.Overestimatingcanresu1.tinsignificantprojectcostoverruns.Underestimatingoutcomescou1.dacce1.eratewearinduceprematurefai1.ure,damageorincreaseproductivep1.ant,equipment,oroperatingsystems1.oss.Offshoreoperationsrequirethata1.1.vesse1.s,insta1.1.ations,system
7、s,procedures,andprocessesinvo1.vedbothaboveandbe1.owthesea1.eve1.aredesignedandapp1.iedtowithstandtheextremitiesofmetoceanconditions.Metoceanforecastsofwind,waves,current,icemovement,andcombinedeffectsareviewedasthecrucia1.e1.ementstofu1.1.ycomprehendinoffshoredesignandengineering.Thisassuresthathig
8、h-riskoperatingactivitiesareidentifiedthatwhenexposedtomoreextrememetoceancondition1.imitsoutsideofwe1.1.sspecificoperatingconditionsguide1.ines/7areacteduponsafe1.yandresponsib1.y.Deepwateroperationsdrivenprimari1.ybymetoceanextremitythatdefinestheoperatingconditionsofcontinuous,restricted,orsuspen
9、dedworkthatresu1.t.Asafety-firstoperationa1.approachmustbeadoptedtoassurethatinexceptiona1.situationa1.circumstanceminima1.1.osttimeresu1.ts.IvpuucDttghttpsd0iar1.l O i 6B97S4)X)4 02282*5.0000441112019 Ekcvicr 1.ed. All rights reserved.Forcemajeure(unavoidab1.eaccidentorcatastrophe)isanevidentoffsho
10、reoperationa1.risktoaccept.Waitingisoftenbyfarthesafestbestpracticejudgmenttoexercisewhenextremeconditionsprevai1.Oneofthefirstitemsataprojectstartisthereforetoconsu1.twithinterna1.orexterna1.specia1.iststoestab1.ishregiona1.metoceanandenvironmenta1.p1.ansandstrategies,thentodiscussidentifyandassess
11、rightfromthestartthemajorhazards/risks.Itisimportantear1.yinaprojecttodecidewhatmetocean,sitesurvey,safewe1.1.1.ocation,environmenta1.base1.inestudies,assessmentreportsareneededtoassurethede1.iveryofoptima1.operationa1.safety,va1.ue,andriskreduction,inregardstometoceanterms.Theendresu1.tistoproducea
12、metoceanregiona1.strategy,estab1.ishsafeoperatingstandards,andde1.iverwe1.1.-specificguide1.inestoshare,distribute,andenab1.ea1.1.operationsteams,intheoffice,externa1.1.yandatthewe1.1.site.Fai1.ingtoexercisethesenecessarymetoceanprocesses,nottoobtainthenecessarydata,notconducttherequiredstudies,notb
13、eingab1.etouti1.izeorreacttorea1.informationinthecorrectmanneris1.ike1.ytoresu1.tincost1.yendangermenttopersonne1.,we1.1.operating1.oss,andenvironmenta1.disruption.Insummary;metoceanmanagementisprimari1.ybasedondataintegritymanagementandqua1.itycontro1.assessmenttodecideifmetoceane1.ementsanddataset
14、sarewe1.1.presented,measuredandrea1.ornot.Thephysica1.metoceanmetricsused(1.-yea10-,or50-yearreturnperioddata)sha1.1.haveaconsiderab1.eimpactonthedesign,engineering,andoperationa1.imp1.ication.Informeddecisionsmustre1.yuponotherevo1.vedstandardmethods,systems,andadetai1.edunderstandingofthedatasourc
15、e,themetoceanprocesses,workf1.owandendresu1.tsinvo1.vedfortheregionorwe1.1.specificsinquestion.Indeepwater;aprojectoftenbeginswithadistinct1.ackofinformationtomakeinformed,data-drivendecisions.Asoundunderstandingoftheendusersapp1.icationisrequiredtomakepragmatic,informedknow1.edge-andexperience-base
16、dchoices.Assumptionsanduncertaintiesmustbewe1.1.reasonedandc1.ear1.ycommunicatedtoensuredataareusedappropriate1.y.Metoceanandoceanworkisa1.sotypica1.1.yconductedviasoftwaremode1.sthatusearigorousdigita1.workf1.owofsystemandprocess.Thisassuresthatcritica1.datamanipu1.ationisfu1.1.ytraceab1.eandcanbee
17、fficient1.yreproducedfo1.1.owingsma1.1.changesatanystageintheana1.ysisprocess.Proprietarysoftwaretoo1.kitsrepeated1.yundergocontinuousdeve1.opmenttoimprovefunctiona1.ity;inc1.udingoperationa1.statisticsandgenerationofextrememetoceanva1.ues.Understandingtheessentia1.processesthatimpactoffshoredeepwat
18、eroperationsisfundamenta1.Thisaprerequisiteforse1.ectionofappropriatedatasourcesandassessmentofdataqua1.ityandintegrityrequiredinc1.usiveofthecharacterizationofa1.1.saidprocessesbytheoperatorspersonne1.Whomusteva1.uatetheuseofspecia1.iststoprovideac1.earandpragmaticinterpretationofmetoceandatatohigh
19、1.ightthekeyfeaturesofdesignandengineeringrisksignificancethatexists.Ibsummarize,inremotedeepwatermetoceanoperatingenvironments,conditionsattheirextremesmustbefu1.1.yunderstoodandaccountedfor.Thischapterout1.inesthebasicguidingprincip1.esofmetoceanaspects.MetoceanOperatingCauseandEffectDuringdeepwat
20、eroperations,theprimarysituationa1.requirementistomaintainthevesse1.anda1.1.associatedequipmentattachedtothewe1.1.frommovingaroundtoomuchorfrequent1.y;withassuredmeasuresandp1.ansinp1.acetodowhatisneededtoprevent,reduce,ormitigateoperatingprob1.ems,de1.ayszdamage,fai1.ure,and1.ossshou1.dextremecondi
21、tionsarise.Whendri1.1.ingfromf1.oatingvesse1.s,aprimaryobjectiveistomaintaina1.1.tubu1.arorriserstringsasnearasvertica1.overthewe1.1.andab1.etocompensateagainstmetoceancauseandeffectsthatwi1.1.changevesse1.movementwithtime.Currentve1.ocity;wind,andcombinedconditionsthatwi1.1.horizonta1.1.ydisp1.ace,
22、pitch,ro1.1.,andheavevesse1.sandassociatedsuspendedtubu1.ars,in1.imitingcircumstancesandsituations,cansevere1.yimpactwe1.1.operations.Be1.owsea1.eve1.regiona1.effectssha1.1.varyasshowninFig.4.1thatcanfurtherimposemajorstressesona1.1.subseawe1.1.scomponentstoconsiderinriserdesign.Atsurface,fog,snow,i
23、ce,temperaturezandheavyraincana1.1.p1.aytheirpart.Whencombinedforcesorhorizonta1.offsetsavesse1.orsystemscomponentresu1.ttobesignificant,itcaninterruptandincreaseoperatingsafetyriskstomoresevereexposure.Metoceanandenvironmenta1.resu1.tantforcesa1.soaffectrigse1.ection,operatingpractices,andoftendefi
24、netheoptima1.seasontominimize“waiting“1.osttime.ThediversityOfmetoceanandenvironmenta1.conditionsfromse1.ecteddeepwaterregionsasi1.1.ustratedinFig.4.1andTab1.e4.1canbec1.assifiedfor1.owtohighrisk,drivenanddependentuponthemetoceane1.ements,conditions,andenvironmentsthatresu1.tthrougheachseason.Adiver
25、serangeofmetoceanhazardsandriskscanu1.timate1.yaffectandimpact;operations,vesse1.s,associatedequipment,systems,we1.1.design,anda1.1.safetyaspects,duetoa1.1.staticanddynamicformsofmetoceanconditionsandsituationsthatprevai1.Environmenta1.ForcesBasedonmetoceanenvironmenta1.conditions,ponentsandsystemsr
26、equiredforstationkeepinganda1.1.activities,theresu1.tantforcesfa1.1.intotwogroups:AerodynamicandHydrodynamic.Aerodynamicforcesresu1.tfromwindforces,snowzrain,etc.andHydrodynamicforcesarea1.1.theforcesactingontheoperatingvesse1.s,inc1.udingcurrent,waves,ortida1.effects.Thecharacteristicsandrea1.ityof
27、combinedenvironmenta1.forcesvarysignificant1.ywithindeepwaterregionsandwe1.1.specificareasasi1.1.ustratedinFig.4.1andTab1.e4.1.Whenperformingdeepwaterstationkeepingorwe1.1.operatingriskana1.ysisandassessingcapabi1.ityp1.otsfordynamicposition,mooringsystems,risermanagementana1.ysis,etc.Deepwateropera
28、tingandevidentfai1.urestestifytowhatcangowrongifnotbeingab1.etorecognize,ana1.yze,identify,riskmanage,andacttocontro1.theextentofmetoceanforcesattheirprobab1.eextremes.Examp1.e:Thegreatesthistorica1.maritime1.ossbyfarisduetovesse1.scapsizingduringtropica1.storms,etc.Furthermoreasdeepwatermigratesint
29、otheseasandoceans,withapreferencetoremainonstationforas1.itt1.eas1-6monthsupto30-40yearsinaproductionscenario.Operatorsmustdemonstratedesign,engineer,andmatchtheoperatingcapabi1.itytoexceedanticipated1.ifecyc1.emetoceanconditions,andassuresafeoperatingmeasuresaremanagedthroughouttoA1.ARP1.eve1.s,i.e
30、.zas1.owasisreasonab1.epracticab1.e.Gu1.fofMexico(Hurricanes/1.oop)II-Wind205042.0m/sWestAfricaBrazi1.Hmax23.2mHs12.5mWavesSurfacecurrent141m/sWind5Q25.0m/sHmax7.1mHs4.0mjWind5Q35.4VsWavesSurfacecurrent2.06m/sHmax14.5mHs7.8m1.DEEPWATERGENERA1.WavesSurfacecurrent110-257m/sMn.temp.4.09C.SeabedCUfrent0
31、.1-0.51m/sMax.temp.30-0oC.Waterdepth2000mMax.temp.30.(FC.Mn.temp.=4O3C.Seabedcurrent0.5WsMax.temp.30.0oC.Mn.temp.=4.0oC.Seabedcurrent0.5m/sWaterdepth1500mWaterdep1.h2000mFIG.4.1DeepwaterEnvironmenta1.Metoceanandoceanographicconditions.FromKingdOffshoreNorway(Ormen1.ange)5Q38.5m/sWaVeSSurfacecunent17
32、5m/sHmax31.5mHs16.5mAt1.anticFrontierFaroe-Shet1.andChanne1.I寸IWind2Q5Q400m/sHmax3.2m-Hs18.0mWavesSurfacecurrent1.96m/sMax.temp.14.0,C.Max.temp.18.5C.M.temp.-1.5C.SeabedCUrfent063msMmtemp.1.9,C.Seabedcurrent0.5sWaterdepth1OOOmWaterdepth700m4DEEPWATERMEToCEANENV-RoNMENTSomDri1.1.ing.DEEPWATERMETOCEAN
33、ENVIRONMENTSTAB1.E4.1DeepwaterExtremeMetoceanConditions1151.ocationWaveHeight(m)WavePeriod(s)WindSpeed(ms)Current(ms)EastKa1.imantan26-7171.5CamposBasin8-1012-15251Gu1.fofMexico111444-481SouthChinaSea12-1413-1445-561.0-2.0NorthernNorthSea15-1615-1738-390.9-1.2WestofShet1.and15-1716-1939-411.0-3.0At1
34、.anticIre1.and16-1816-2039-411.0-1.5WringBasinNorway14-1516-1737-391.0-1.5WestAfrica4-610-16200.3-0.64681011m=1320263336ft,20253035m_44.755.967.178.3mi1.e0.250.50.751.01.25m_0.81.62.53.34.1ft0.250.50.7511.250.51151.92.4knot144640S89.5h1.5S4.9S1.5S2.9154945100.72.06.623.9165250111.82.58.22.54.9175655
35、123593.09.83.05.818JSource：KingdomDri1.1.ing,December2017.Techno1.ogyNote:Maximumstormconditionsaregenera1.1.ydefinedfromtheoretica1.andempirica1.determinations.However,newwavemeasurementsfromadvancingtechno1.ogiessuchas1.aserandradarrecordingshaveshowninordinatediscrepanciesinsuchestimates.EXAMP1.E
36、The100-yearwaveinextremeAt1.anticmarginsisnowunderstoodtobeperhaps2-3mhigherthanexistingstructuresareoftendesignedfor,basedonnewtechno1.ogydatapresented.Inaddition,becausethewavecrestmeasurementuseddeterminesthedeckheightoffixedorf1.oatingstructures(ifatoperatingdrafts),theindustrycannotaddressthese
37、differenceswithoutexecutingfurtherinvestigation.Ana1.ysisofexistingdataandaneva1.uationofothermeasuringtechniquesandmeasurementsarea1.1.examp1.esoftaskstobeperformedparticu1.ar1.yindeepwaterwherehigherrisksanduncertaintiesexist.MetoceanHazardsMetoceanhazardsimpactingdeepwaterwe1.1.operationsand1.imi
38、tsaredrivenby:1. Poorvisibi1.ity2. Highwavesandcurrents,1.oopandeddycurrents3. Extremewinds;hurricanes,typhoons,tornadoes,andcyc1.ones4. Combinedforcesofwindwavesandcurrents5. Heavyrain,snow,ice1.oading.Factorsthatresu1.tinhazardous/risk-basedoperatingconditionsandsituationa1.eventsaremanagedandcont
39、ro1.1.edthroughanunderstanding,determinationzandeva1.uationof:1. Extremereturnperiods,i.e.zprobabi1.itythatthe1-,10-z50-,or100-yearstormwi1.1.resu1.t(a) Atoperating1.ocations,(b) Duringtheoperatingperiod.2. WhenzzWe1.1.-SpecificOperating1.imitszzareexceeded.(a) Pitch,ro1.1.,heave,andoffset,disp1.ace
40、ment,safeworking1.imitsexceeded.(b) Operationsarerestrictedorsuspended.(c) P1.annedand/orunp1.anned(emergency)contingentactionsenforced.3. Capabi1.itytomaintainingvesse1.,RCworsupp1.yvesse1.sonstation.(a) Operationsarerestrictedorsuspended.(b) P1.annedand/orunp1.anned(emergency)disconnectfromwe1.1.s
41、resu1.t.(c) Unab1.eto1.oadoff1.oadtoo1.s,equipmentetc.Supp1.ychainha1.ted.4. Saferisermanagementand/orassociatedoperatingdifficu1.tiescapabi1.ity.5. Pipeandtubu1.arhand1.ingcapabi1.itiesinexcessiverigmotionordisp1.acement.6. Inabi1.itytof1.yhe1.icopters,crewchangebyboat,etc.Personne1.cannotbeevacuat
42、edfromfixedinsta1.1.ationsorrigs.7. Equipmentfitnessforpurposeorresu1.tingineffectiveness,inefficiencies,orfai1.ure.8. Emergencyandcontingentcapabi1.ities:For1.ossofPoWeUrigdriveordriftoff,majororsuddenequipmentoroperationa1.fai1.ure.ManagingDeepwaterMetoceanEnvironmentsIfprobabi1.itypredictsthatext
43、rememetoceanandenvironmenta1.forcesresu1.tduringactiveoperatingperiodsasshowninFig.4.2.Farmorecarefu1.anddetai1.edp1.anning,design,engineering,andmoretime1.yandaccurateforecasting,withc1.oser1.oca1.monitoringmustbeaffordedduetothegreaterriskanduncertaintyofeventsthatcanresu1.t.Inthep1.anningphase,ga
44、theringandassessingregiona1.andsite-specificdata,studiesareadvisab1.eparticu1.ar1.ywhenmoreextrememetoceanrisksexist.Theresu1.tingcauseandeffectofwater-co1.umn,currents,WaVeSinds,seaf1.oor,sha1.1.owtop-ho1.esoi1.andgeo1.ogicconditionsa1.1.canadverse1.ycombinetosevere1.yimpactoperatingconditionsandwh
45、ya1.1.keyaspectsmustbedu1.yrisked,managedzandcontro1.1.ed.Prewe1.1.operationa1.studiesmustbeconductedtobetterunderstand,assess,andaddresshowtocontro1.regiona1.metoceanhazardsateachspecific1.ocation.Metoceaninformationandevidentdatacanthenputtova1.uab1.eusesothatpersonne1.invo1.vedinthep1.anningorsup
46、ervisionofwe1.1.operationshaveaccesstoa1.1.necessarydatarequired:wind,ave,current,tida1.forecasts,andcombinedeffects,andindirectdatasuchasFIG.4.2DeepwaterrigoperatingontheNorwegianContinenta1.she1.f.Source:NorwegianDeepwaterProgram1996-2016.informationonmigratingsediments,surfaceandnearsurfacefau1.ts,sha1.1.owhazards,irregu1.arseaf1.oortopography,seaf1.oorsoi1.characteristics,manmadeobjects,environmenta1.assessment,samp1.ingrequirements,shipping,andfishingoperations.Programandprojectaspectstoconsiderforp1.anning,administrating,andimp1.ementationinc1.udethefo1.1.
