油氣儲(chǔ)運(yùn)專業(yè)英語(英漢互譯)

./Chapter1OilandGasFields第1章油氣田1.1AnIntroductiontoOilandGasProduction1.1石油和天然氣生產(chǎn)的介紹Thecomplexnatureofwellstreamsisresponsibleforthecomplexprocessingoftheproducedfluids<gas,oil,water,andsolids>.Thehydrocarbonportionmustbeseparatedintoproductsthatcanbestoredand/ortransported.Thenonhydrocarboncontaminantsmustberemovedasmuchasfeasibletomeetstorage,transport,reinjection,anddisposalspecifications.Ultimatedisposalofthevariouswastestreamsdependsonfactorssuchasthelocationofthefieldandtheapplicableenvironmentalregulations.Theoverridingcriterionforproductselection,construction,andoperationdecisionsiseconomics.油氣井井流的復(fù)雜性質(zhì),決定了所產(chǎn)流體<氣、油、水和固體>的加工十分復(fù)雜。必須分出井流中的烴類,使之成為能儲(chǔ)存和/或能輸送的各種產(chǎn)品;必須盡可能地脫除井流中的非烴雜質(zhì),以滿足儲(chǔ)存、輸送、回注和排放的規(guī)。各類廢棄物的最終處置取決于各種因素,如油氣田所處地域和所采用的環(huán)保規(guī)定等。經(jīng)濟(jì)性是決定油氣田產(chǎn)品設(shè)計(jì)、建筑和操作決策的最重要準(zhǔn)則。Fig.1-1isacomprehensivepictureoftheindividualunitoperationscarriedoutinfieldprocessing.Allthevariousmodulesshownwillnotallbepresentineverysystem.Furthermore,themodulesusedinagivenapplicationmaynotbearrangedintheexactsequenceshown,althoughthesequenceis,ingeneral,correct.Theselectionandsequencingofmodulesisdeterminedduringthedesignphaseoffielddevelopment.圖1-1表示在礦場進(jìn)行的各種單元操作的綜合圖。在各系統(tǒng)不一定有圖1--}所示的全部操作模塊。盡管圖中所示的加工順序通常是正確的,但在某一特定使用情況下,模塊的布置可能會(huì)與圖中所示的順序不同。在油氣田開發(fā)設(shè)計(jì)階段確定模塊的選擇和排列順序。AsshowninFig.1-1,theindividualphases<gas,liquidhydrocarbon,liquidwater,andsolids>shouldbeseparatedfromeachotherasearlyaspractical.Individualstreamscanthenbetreatedwithlesstechnicaldifficultyandmoreeconomically.HartleyandBinJadid<1989>illustratehowlabandfieldtestsperformedbeforeconstructioncanidentifyandminimizefutureproductionandprocessingproblemssuchasscaling,foaming,emulsionformation,waxdeposition,andhydrateformation.Processingoftheseparatedstreamsisnowreviewedbrieflybecausemanyoftheindividualunitoperationsarediscussedindetailinsubsequentchapters.如圖1-1所示,應(yīng)盡早將各股流體<氣、液態(tài)烴、液態(tài)水和固體>分離。這樣,單獨(dú)處理各股流體時(shí),技術(shù)難度較小,也較經(jīng)濟(jì)。Hartley和BinJadid<19$9闡明了在建設(shè)前進(jìn)行的室和現(xiàn)場試驗(yàn)可以發(fā)現(xiàn)并減少將來在生產(chǎn)和加工中可能出現(xiàn)的問題,如結(jié)垢、發(fā)泡、形成乳狀液、結(jié)蠟以及生成水合物等,現(xiàn)在簡要介紹被分離的各股流體的加工,在后續(xù)章節(jié)中將詳細(xì)討論其中的許多單元操作。1.1.1GasProcessing1.1.1氣體加工AsshowninFig.1-1,gasprocessingbeginswithtreating,ifnecessary,toremovetheacidgases-hydrogensulfideandcarbondioxide.Bothgasesareverycorrosivewhenliquidwaterispresentandhydrogensulfideismosttoxic.Environmentalregulationsalmostalwaysprohibitthereleaseofsignificantamountsofhydrogensulfidetothesurroundings.Conversiontoelementalsulfurisbecomingincreasinglynecessary.如圖1-Z所示,氣體加工<若需要>從脫除酸氣<H2S和CO2>開始。當(dāng)存在液態(tài)水時(shí),這兩種氣體有極強(qiáng)的腐蝕性,而且H2S極具毒性。環(huán)保法規(guī)幾乎都禁止向周圍環(huán)境排放大量H2S,而且正愈來愈多地要求將H2S轉(zhuǎn)變?yōu)樵亓?。Gassweeteningusuallyusesaqueoussolutionsofvariouschemicals.Therefore,sweeteningwillprecededehydration.Dehydrationisoftennecessarytopreventtheformationofgashydrates,whichmayplughigh-pressureprocessingequipmentorpipelinesathighpressureandattemperaturesconsiderablyhigherthan32°F<0°C>.天然氣脫酸氣常使用各種化學(xué)劑的水溶液,因而脫酸氣應(yīng)在氣體脫水之前進(jìn)行。為防止生成氣體水合物,常需進(jìn)行脫水。在高壓和比32°F<0℃>高的溫度下,水合物可能堵塞高壓工藝設(shè)備和管線。Gasthatcontainsconsiderableamountsofliquefiablehydrocarbons<ethaneorpropaneandheavier>canproducecondensateuponcompressingorcooling.Thecondensatemaycausedifficultyinpipeliningorsubsequentprocessing.Fieldprocessingtoremovethesenatural-gasliquids<NGL>,sometimesreferredtosimplyascondensate,maybeeconomicalormayberequiredtomeetahydrocarbondew-pointspecification.Inremotelocationssuchprocessingisgenerallyavoidedifpossible.Recoveredcondensatemay,inturn,havetobestabilizedbyremovingdissolvedgaseouscomponentstoobtainatransportableproduct.含有大量可液化烴類<C2+或C3+>的氣體,在壓縮或冷卻時(shí)一可能產(chǎn)生凝析油。凝析油會(huì)給管輸和后續(xù)加一帶來困難。在礦場脫除這些天然氣液體<NGL,有時(shí)簡稱為凝析油>可能是經(jīng)濟(jì)的,或?yàn)闈M足烴露點(diǎn)規(guī)定所必需的。在邊遠(yuǎn)地區(qū)應(yīng)盡一量避免脫除凝析油的工作?；厥盏哪鲇捅仨氝M(jìn)行穩(wěn)定,脫除溶解氣組分,以獲得可輸送的產(chǎn)品。1.1.2OilProcessing1.1.2原油加工Afterfreewaterremoval,producedoiloftencontainsexcessiveresidualemulsifiedwater。].Treating,alsocalleddehydration,isrequiredtoreducethewatercontenttoavalueacceptablefortransportationorsales.Dehydrationshouldbeaccomplishedusingthemosteconomiccombinationoffourfactorsortechniques;namely,residencetime,chemicaladdition,heat,andelectrostaticfields.Dilutionwatermustoccasionallybeaddedtoreducethesaltcontentoftheresidualemulsion<i.e.,thesalescrudeoil>toasuitablylowlevel.IntheUnitedStates,desaltingisusuallyperformedintherefinery；overseas,desaltingissometimesperformedinthefield.脫除游離水后,生產(chǎn)的原油常含有過量的殘余乳化水。含有過量殘余乳化水的原油需要進(jìn)行處理<也稱脫水>,將水含量降至運(yùn)輸和銷售允許的限度。可應(yīng)用四種技術(shù)的最經(jīng)濟(jì)組合實(shí)施脫水,即停留時(shí)間、化學(xué)添加劑、加熱和靜電場。有時(shí)還必須摻人稀釋水,將殘余乳狀液<即銷售原油>的鹽含量降低至合理的低濃度。美國,脫鹽常在煉廠進(jìn)行；美國以外地區(qū),脫鹽有時(shí)在礦場進(jìn)行。Hydrogensulfideincrudeoilislimitedtoreducehandlingandtransportationdifficultiesbecauseofitsextremetoxicityandcorrosiveness.Gasstrippingorheatingisusuallyusedforhydrogensulfideremovalorsweeteningasisdiscussedlatterly.由于H2S具有劇毒和腐蝕性,故應(yīng)限制原油H2S的含量,以降低原油裝卸、沛在和輸送過程的困難。如在后續(xù)容中討論的那樣,常用氣提或加熱方法脫除原油的H2S,或使其"甜化"。Crudeoilstabilizationreferstoloweringthevaporpressuretoavaluethatwillallowsafehandlingandtransport.Vaporpressurecontrolisobtainedbystageseparation,reboileddistillation,oracombinationofthetwo.Duringstabilizationsomeofthemorevolatilehydrocarbonsareremovedasvaporandthisgasphaseentrainshydrogensulfideandothervolatilesulfurcompoundsfromthesourcrudeoil.Additionalsweeteningmaynotberequired.原油穩(wěn)定是指將蒸氣壓降低至某一數(shù)值,在該蒸氣壓下原油可安全地裝卸、儲(chǔ)存和運(yùn)輸。多級(jí)分離、再沸蒸餾或多級(jí)分離與再沸蒸餾相結(jié)合,來控制原油蒸氣壓。在穩(wěn)定過程中,某些揮發(fā)性強(qiáng)的烴類成為蒸氣從原油分出,這種烴類氣體還從酸性原油帶出H2S和其他揮發(fā)性強(qiáng)的硫化物。原油也可能不需要專門的脫硫或"甜化"處理。1.2BriefDescriptionofCrudeOilSurfaceTreatment1.2原油地面處理簡介Wellfluidsareoftenacomplexmixtureofliquidhydrocarbons,gas,andsomeimpurities.Itisnecessarytoremovethegasandsomeimpuritiesfromtheliquidhydrocarbonsbeforetheyarestored,transported,andsold.Liquidhydrocarbonsandobjectionableimpuritiesmustalsoberemovedfromnaturalgasbeforethegasgoestoasalesline.Impuritiesthatmightbefoundinsomewellstreamsarehydrogensulfide,carbondioxidefreewater,watervapor,mercaptans,nitrogen,helium,andsolids.Nearlyallofsiteimpuritiescausevarioustypesofoperatingproblems.井流通常是液態(tài)烴、氣體和某些雜質(zhì)的復(fù)雜混合物。在液態(tài)烴儲(chǔ)存、輸送和銷售前,必須從浪態(tài)烴中脫除氣體和某些雜質(zhì)。氣體進(jìn)人銷售管道前,也必須從天然氣中脫除液態(tài)烴和有害雜質(zhì).在某些并流中,可能存在的雜質(zhì)是硫化氫、二氧化碳、游離水、水蒸氣、硫醇、氮、氦和固體雜質(zhì)。幾乎所有的雜質(zhì)都會(huì)引起各種操作問題。Theseparationofnaturalgas,liquidhydrocarbons,andimpuritiesisaccomplishedbyvariousfield-processingmethods,dependinguponthecompositionofthewellstreamandthedesiredendproduct.Thosemethodsincludetime,chemicals,gravity,heat,chemicalsorelectricalprocesses,andcombinationsofthese.根據(jù)井流的組成和要求的終端產(chǎn)品,可采用各種現(xiàn)場加工方法實(shí)現(xiàn)天然氣、液態(tài)烴和雜質(zhì)的分離。這些方法包括時(shí)間、化學(xué)藥品、重力、熱、機(jī)械或電加工,以及上述方法的綜合運(yùn)用。1.2.1Separators1.2.1分離器Separationofwell-streamgasfromfreeliquidsisthemostcommonandsimplestformoffieldprocessing.Theequipmentmostwidelyusedforthistypeofprocessingisreferredtoasaseparator.Theseparationofnaturalgasfromliquidsand/orimpuritiesmaseparatorcombinesgravity,time,mechanicalprocesses,andoccasionallychemicals.液體與井流氣的分離是現(xiàn)場加工最普遍和最簡單的方式。這類加工中最常用的設(shè)備稱為分離器。在分離器,從液體和/或雜質(zhì)中分出天然氣時(shí)可綜合使用重力、時(shí)間和機(jī)械方法,偶爾也采用化學(xué)藥劑。Thesizeoftheseparatorisdependentuponrateofflowofthenatural^asand/orliquidsgoinginthevessel.Theoperatingpressureofthevesselisdependentuponthepressureofthegassalesline,theflowingpressureofthewell,andoperatingpressuredesiredbytheleaseoperator.分離器的大小取決于進(jìn)人分離器的天然氣流量和/或液體流量。容器的操作壓力取決于氣體銷售管線的壓力、井的流動(dòng)壓力和礦場操作人員要求的操作壓力。Separatorsarebuiltinvariousdesigns,suchasvertical,horizontalandspherical.Theinternalsofthevessel.toaidinthemechanicalseparationofthegasandliquids,areofaspecialdesign,dependinguponthemanufacture.Althoughmostseparatorsaretwo-phaseindesignseparatingthegasandliquids,theycanbebuiltthree-phaseloseparatenaturalgas,liquidhydrocarbons,andfreewater<Fig.1-2>.分離器有各種不同設(shè)計(jì),如立式、臥式和球形分離器。促進(jìn)氣液機(jī)械分離的容器部構(gòu)件是由制造商專門設(shè)計(jì)的。盡管設(shè)計(jì)中多數(shù)分離器只分離氣液兩相,但能制造分離天然氣、液態(tài)烴和游離水的三相分離器<圖1-2>。1.2.2OilTreating1.2.2原油處理Whencrudeoilisproduced,variousamountsofgas,water,andotherimpuritiesaremixedwiththeoil.Someofthismixturecomesasfreeoil,someasfreewater,andsomeasahomogeneousmixtureknownasanemulsion.Thegas,water,andotherimpurities<knownasbasicsedimentandwater>mustberemovedbeforesellingtheoil.Thisseparationprocessiscalledoiltreating.采出的原油會(huì)混有不同數(shù)量的氣、水和其他雜質(zhì)。這種混合物中有些為原油,有些為游離水,有些為被稱作乳狀液的均勻混合物。原油銷售前必須脫除氣體、水和其他雜質(zhì)<稱為底部沉積物和水>。這種分離過程稱為原油處理。Treatingsystemsareimportantpartsofleaseequipment.Experienceinaparticularfieldorareaisvaluableindeterminingthebestequipmentfortheapplication.處理系統(tǒng)是礦場設(shè)備的重要組成部分。在確定原油的最佳處理設(shè)備時(shí)是有價(jià)值的,在特定油田和地區(qū)的經(jīng)驗(yàn)十分重要。Inselectingatreatingsystem,anumberoffactorsshouldbeconsideredtodeterminethemostdesirablemethodoftreatingthecrudeoiltopipelinerequirements.Someofthesefactorsare:為了確定原油的最佳處理方法,使之滿足管輸要求,在選擇處理系統(tǒng)時(shí)應(yīng)考慮許多因素。其中的一些因素是：<1>Tightnessofemulsion.〔1乳液的牢固程度。<2>Specificgravityoftheoilandproducedwater.〔2油和采出水的相對密度。<3>Corrosivenessoftheoil,gas,andproducedwater.〔3油,氣,和采出水的腐蝕性。<4>Scalingtendenciesoftheproducedwater.〔4采出水的結(jié)垢趨勢。<5>Quantityoffluidtobetreatedandpercentofwaterinthefluid.〔5需處理的流體數(shù)量和流體的水含量。<6>Availabilityofsaleslineforthegas.〔6是否有氣體銷售管線。<7>Desirableoperatingpressurefortheequipment.〔7設(shè)備所需的操作壓力。<8>Paraffin-formingtendenciesofthecrudeoil.〔8原油的結(jié)蠟傾向。Oil-fieldemulsionsareusuallyofthewater-in-oiltype;however,afewoftheemulsionsareoil-in-watertypeandarecalledreverseemulsions.Emulsionsarecomplexandeachshouldbeconsideredindividually.油田乳狀液通常為油包水型,個(gè)別情況為水包油型,并稱為反相乳狀液。乳狀液非常復(fù)雜,對每一種乳狀液都應(yīng)單獨(dú)考慮。Inordertobreakacrudeoilemulsionandobtaincleanoil,itisnecessarytodisplacetheemulsifieranditsfilm.Thisbringsaboutthecoalescenceofdropletsofwaterandfurnishesameansandtimeperiodofundisturbedsettlingofthecoalescedwaterdrops.Thereareseveralmethodsusedinconjunctionwithoneanotherto"treat"anoilemulsion.為使原油乳狀液破乳并得到凈化油,需要一置換乳化劑及其薄膜。這樣可促使水摘聚結(jié)、并并為聚結(jié)水滴提供無干擾的沉降時(shí)間和沉降方法。處理原油乳狀液有多種彼此組合的方法。1.2.5VerticalTreaters1.2.5立式處理器Themostcommonlyusedsingle-wellleasetreateristheverticaltreaterasshowninFig.1-5.Flowentersthetopofthetreaterintoagasseparationsection.Caremustbeexercisedtosizethissectionsothatithasadequatedimensionstoseparatethegasfromtheinletflow.Ifthetreaterislocateddownstreamofaseparator,thischambercanbeverysmall.Thegasseparationsectionshouldhaveaninletdiverterandamistextractor.圖1-5所示的立式處理器是最常用的礦場單井處理器。井流進(jìn)入處理器頂部的氣體分離段。在確定該段尺寸時(shí),應(yīng)使其有有足夠的空間寸來從井流中分離出氣體。如果處理器位于分離器下游,氣體分離段可以很小。氣體分離段應(yīng)有一個(gè)入口分流器和捕霧器。Theliquidsflowthroughadowncomertothebaseofthetreater.whichservesasafree-waterknockoutsection.Ifthetreaterislocateddownstreamofafree-waterknockout,thebottomsectioncanbeverysmall.Ifthetotalwollstreamistobetreatedthissectionshouldbesizedfor3to5minutesretentiontimeforboththeoilandthewatertoallowthefreewatertosettleout.Thiswillminimizetheamountoffuelgasneededtoheattheliquidstreamrisingthroughtheheatingsection.Theendofthedowncomershouldbeslightlybelowtheoilwaterinterfaceto"waterwash"theoilbeingtreated.Thiswillassistinthecoalescenceofwaterdropletsintheoil.液體通過降液管流至處理器底部,該段為游離水分離段。如果處理器位于游離水分離器下游,則該段可以很小。如果要處理全部井流,以油、水在該段都停留3-5min來確定該段的大小,以便游離水沉降。分出游離水后,將減少向上通過加熱段液流所需的加熱燃料氣為了用水洗滌被處理的原油,降液管的底端應(yīng)略低于油水界面。水洗將促進(jìn)原油水滴的聚結(jié)。Theoilandemulsionrisesovertheheaterfire-tubestoacoalescingsectionwheresufficientretentiontimeisprovidedtoallowthesmallwaterparticlesintheoilcontinuousphasetocoalesceandsettletothebottom.原油及其乳狀液上升,通過加熱器火筒至聚結(jié)段。聚結(jié)段可提供足夠的停留時(shí)間,便連續(xù)相原油的水滴聚結(jié)并沉降至處理器底部Treatedoilflowsouttheoiloutlet.Anygas,flashedfromtheoilduetoheating,flowsthroughtheequalizinglinetothegasspaceabove.Oillevelismaintainedbypneumaticorleveroperateddumpvalves.Oil-waterinterfaceiscontrolledbyaninterfacecontroller,oranadjustableexternalwaterleg.處理后的原油從油出口流出。由于加熱,從原油閃蒸出的氣體通過平衡管線流入處理器頂端的氣體空間。氣動(dòng)或連桿操作的出油閥可控制油面液位,由界面控制器或外部可調(diào)出水管線控制油水界面。Thedetaileddesignofthetreater,includingthedesignofinternals<manyfeaturesofwhicharepatented>shouldbetheresponsibilityoftheequipmentsupplier.處理器及其部構(gòu)件<構(gòu)件的許多特點(diǎn)都有相應(yīng)專利>的詳細(xì)設(shè)計(jì)應(yīng)由設(shè)備供應(yīng)商負(fù)責(zé)。1.2.6StabilizationandSweeteningofCrudeOil1.2.6原油的穩(wěn)定和脫酸Dissolvedgasinthewellheadcrudeoilmustberemovedtomeetpipeline,storage,ortankerReidvaporpressure<RVP>specifications.Whentheoilisessentiallyfreeofdissolvednaturalgas,or"dead"thenitcanbestoredinaventedtankatatmosphericpressuresubject,ofcourse,toemissionregulations.Thepresenceofthemostvolatilehydrocarbons<C1,C2,C3,etc.>increasestheRVPdramatically.Removalofthesedissolvednatural-gascomponentsiscalledcrudeoilstabilization.必須脫去井口原油的溶解氣,以滿足管道、儲(chǔ)存或油輪運(yùn)輸對雷特蒸氣壓的技術(shù)規(guī)定。只有當(dāng)原油基本上沒有溶解天然氣<或稱"死油">并滿足廢氣排放規(guī)定時(shí),才能儲(chǔ)存在常壓通風(fēng)儲(chǔ)罐。原油存在揮發(fā)性極強(qiáng)的組分<C1,C2,C3,等>時(shí),將極增加雷特蒸氣壓。脫除這些溶解的天然氣組分稱為原油穩(wěn)定。TheRVPisusuallysetintherangeof10-12psia,whichgenerallyyieldsatruevaporpressure<TVP>—or,moreproperly,abubblepointpressureat100。F-ofslightlyhighervalue,13—15psia.OtherimportantspecificationsthatmustbemetareBS&WandH2Scontent.Hydrogensulfidespecificationsareusuallyintherangeof10-60ppm<Moins,1980>.通常,設(shè)定的雷特蒸氣壓圍為14--12psia,雷特蒸氣壓<RVP>一般比真實(shí)蒸氣壓〔TVP,確切的說是1440F下的泡點(diǎn)壓力略低,真實(shí)蒸氣壓約為13--15psia。對原油的其他重要規(guī)定還包括水和懸浮固體含量以及H2S含量。對H2S含量的規(guī)定圍常為10-60ppm〔Moins,1980。Oftenaconsiderableamountofgasisdissolvedincrudeoil.Hydrocarbonsareusuallyworthmoreasliquid<i.e.,inthecrudeoilphasethaninthevaporornaturalgasphase>,evenwhenassociatedgasisusedforLNG[I8]orwhenthegasissoldandcondensateisextracted.原油常溶有相當(dāng)數(shù)量的氣體。液態(tài)烴類的價(jià)值一般較高<即烴類在原油比在蒸氣或天然氣的價(jià)值高>,即使是伴生氣用作制造液化天然氣,或從氣體回收凝析油、銷售氣體,其價(jià)值也低于原油。AsecondpossiblebenefitofspikingcrudeoilwithlighthydrocarbonsisthepotentialforincreasedpriceduetoincreasedAPIgravity.Thisincreaseisusuallysmall,however—lessthanonedegreeAPI—andthepriceincreaseisalsomodest,about10cents/bblper°APIincrease.用輕烴摻入原油的另一好處是,由于API相對密度增加,可提高原油售價(jià)。相對密度的增加一般很小,小于10API,而價(jià)格也溫和地增加。每增加10API,每桶原油約增加10美分。Aspreviouslydiscussed,sourcrudesdocontainsulfurcompoundsingeneralandhydrogensulfideinparticular,Stabilizationmustalsoremovethevolatilesulfurcompoundstomeetsalesortransportspecifications.如前所述,酸性原油一般總含有硫化物,特別是含有H2S。穩(wěn)定處理時(shí)也必須脫除揮發(fā)性硫化物,以滿足銷售和輸送的技術(shù)要求。Theeconomicgoalofstabilizationistomaximizestock-tankoilrecoverywhilemeetinvaporpressureandH2Scontentspecifications,aswellasBS&W.Butanesincreasethevaporpressureofcrudeoilconsiderably,sincethetruevaporpressureofi-C4andn-C4are72.6and52.1psia,respectively.ControlofthebutanecontentcontrolstheRVPandTVP.在滿足蒸氣壓、H2S和固體懸浮物及水含量的技術(shù)要求下,使礦場儲(chǔ)罐原油收率最高是原油穩(wěn)定的經(jīng)濟(jì)目的。由于正、異丁烷的絕對真實(shí)蒸氣壓分別為72.6psi和52.1psi,故丁烷對原油蒸氣壓的增加有重要影響?？刂贫⊥楹烤涂刂屏薘VP和TVP。ThetechnicalgoalofstabilizationistoremoveC1,C2,andC3ascompletelyaspossiblewhileleavingthemaximumamountsofC4<andC5andheavier>inthecrudeoil.穩(wěn)定的技術(shù)目的是盡可能地完全脫除C1,C2,和C3。并在原油留下盡可能多的C4,〔以及C5和重于C5的組分。Crudeoilcanbestabilizedbypassingitthroughaseriesofflashdrumsorvapor-liquidseparatorvesselsatsuccessivelylowerpressures.Traytowerswithreboilers,alternativelyorinconjunctionwithseparators,arealsoused,thoughlessoften.讓原油通過一系列逐步降壓的閃蒸罐或氣一液分離器可以使原油穩(wěn)定,也可以使用帶重沸器的板式塔或采用板式塔與分離器結(jié)合的方式使原油穩(wěn)定,但使用較少。Stabilizationcanalsosweetenthecrudebecausethechiefsulfur-containingorsourcontaminant,H2S,hasaboilingpointof-76.5T-intermediatetothatofethaneandpropane.Incidentally,dissolvedradongaswillalsoberemovedwiththelighthydrocarbons.itsboilingpointis-79.2°F.Radonradioactivitymustbeconsideredverycarefully.由于主要的含硫或酸性雜質(zhì)為H2S,它的沸點(diǎn)為一76.5°F,介于乙烷和丙烷之間,故穩(wěn)定過程也使原油脫酸。順便提及,氡的沸點(diǎn)為一79.20F,在穩(wěn)定過程中溶解在原油中的氡氣也會(huì)隨輕烴一起從原油脫除。必須十分謹(jǐn)慎地對待氡的放射性。So-calledsourcrudeoilcontainsH2Sandothersulfur-containingcompounds.EvensmallamountsofH2Smakethecrudeoilextremelytoxicandcorrosive.Theothersulfurcompoundsarefarlesstoxicandnotsoaggressivelycorrosive,eventhoughsomehaveequallystrongodors.ThepresenceofliquidwaterexacerbatesthecorrosionasdoesCO2.PersonnelsafetyandequipmentprotectionrequirethatH2Sand<toalesserextent>othersulfurcompoundsberemoved.所謂酸性原油,是指含有H2S和其他含硫化合物的原油。即使含少量硫化氫,也使原油具有很強(qiáng)的毒性和腐蝕性。盡管某些硫化物有與H2S相同的強(qiáng)烈氣味,但這些硫化物的毒性和腐蝕性遠(yuǎn)低于H2S。與CO2類似,液態(tài)水的存在也會(huì)激化腐蝕。從人員安全和設(shè)備防護(hù)的角度來看,應(yīng)脫除H2S,并在某種程度上同時(shí)脫除其他硫化物。1.3TreatingOilFieldEmulsions1.3油田乳狀液的處理1.3.1TheoryofEmulsions1.3.1乳狀液理論Anemulsionisacombinationoftwoimmiscibleliquids,orliquidsthatdonotmixtogetherundernormalconditions.Oneoftheliquidsisspreadout,ordispersed,throughouttheotherintheformofsmalldroplets.Thesedropletscanbeofallsizes,fromfairlylargetoverysmall.Sometimesdropletsaresosmallthatmorethanfiftyofthemcouldbeplacedontheheadofapin.Astableemulsionisanemulsionthatwillnotbreakdownwithoutsomeformoftreating.乳狀液是兩種不相溶液體或在正常條件下不能混合在一起的多種液體的混合物。其中,一種液體以小液珠形式完全分散于另一種液體。這些液珠的粒徑是各不相同的,從很大至非常細(xì)小。有時(shí),液珠小至可在一枚大頭針端部放置50多個(gè)液珠。Threeconditionsarenecessaryfortheformationofastableemulsion.穩(wěn)定乳狀液是一種不采用某種處理方法不能破乳的乳狀液。形成穩(wěn)定乳狀液必須具備三個(gè)條件:<1>Theliquidsmustbeimmiscible.〔1各液體必須是互不相溶的;<2>Theremustbesufficientagitationtodisperseoneliquidasdropletsintheother.〔2需要有足夠的攪動(dòng),使一種液體成為液珠分散于另一種液體;<3>Theremustbeanemulsifyingagent,oremulsifier,present.〔3需要有乳化劑。Toformastableemulsionofcrudeoilandwater,anemulsifyingagentmustbepresent.Emulsifyingagentscommonlyfoundinpetroleumemulsionsincludeasphalt;resinoussubstances;oilsolubleorganicacids;andotherfinelydividedmaterialsthataremoresoluble,wettable,ordispersableinoilthaninwater.Somefinelydividedsolidsareiron,zincandaluminumsulfates,calciumcarbonate,silica,andironsulfide.Eachoftheseemulsifiersusuallyoccursasafilmonthesurfaceofthedisperseddroplets.為形成原油和水的穩(wěn)定乳狀液,必須要有一種乳化劑。在石油乳狀液發(fā)現(xiàn)的乳化刑通常包括瀝青、樹脂物質(zhì)、油溶性有機(jī)酸以及那些更易溶解于油中、易為油所潤濕或易在油中分散的細(xì)顆粒物質(zhì)。某些細(xì)顆粒固體為鐵、鋅和硫酸鋁、碳酸鈣、硅和硫化鐵。上述每種乳化劑一般都會(huì)在分散液珠表面形成薄膜。Inanemulsion,theliquidthatisbrokenupintodropletsisknownasthediscontinuous,dispersedorinternalphase.Theliquidthatsurroundsthedropletsisknownasthecontinuousorexternalphase.Anemulsionofoilandwatermayhaveeitheroilorwaterasthedispersedphase,dependingonthecharacteristicsoftheemulsifyingagent,butinmostcasesitisthewaterthatisdispersedasdropletsintheoil.乳狀液破碎為液珠的液體稱為一作連續(xù)相,也稱分散相或相。液珠周圍的液體稱為連續(xù)相或外根據(jù)乳化劑的性質(zhì),油水乳狀液油或水均可成為分散相,但多數(shù)情況下水以水珠分散于油中。Anoil-wateremulsionmaycontainfromatraceto90percentormorewater.Also,anemulsionmaybetight<difficulttobreak>orloose<easytobreak>.Whetheranemulsionistightorloosedependsonseveralfactors,whichincludethepropertiesoftheoilandwater,thepercentageofeachfoundintheemulsion,andthetypeandamountofemulsifierpresent.油水乳狀液的水含量可從含微量水<痕跡>至90%或90%以上.乳狀液可能很牢固<難于破乳>,也較疏松<易于破乳>。乳狀液破乳的難易取決于若干因素,包括油水性質(zhì)、乳狀液油和水的百分含量、乳狀液乳化劑的類型和數(shù)量。Occasionallyemulsionsproducedfromsomefieldsarethereversetypeinwhichtheoilistheinternalphaseandisdispersedasdropletsinwater.Sometimes,butveryrarelyoilisproducedinadualemulsioninwhichthedispersedphaseisdropletsofoil-inwateremulsionandtheexternalphaseisoil.些油田偶爾會(huì)產(chǎn)生反相型乳狀液,即油為相并呈油珠分散于水中。在極少數(shù)的情況下,原油以雙重乳狀液采出,分散相是水包油型乳狀液,外相為油。Inwater-in-oilemulsion,therearetwoforcesindirectopposition.Oneforceisthefilmofemulsifyingagentthatsurroundsthewaterdroplets.Thisforcetendstopreventthedropletsfrommergingtogethertoformlargerdrops,evenwhenthedropletscollide.Theotherforceistheoppositetendencyofwaterdropletstojointogethertoformlargerdrops.Thelargerdropsyieldtotheforceofgravityandsettleout.Therefore.!obreakdownapetroleumemulsion,thepropertiesoftheemulsifyingagentmustbeneutralizedordestroyedsothatthedropletsofwatermayunite.Manyproceduresfortheneutralizationanddestructionoftheemulsifyingagenthavebeendeveloped.在油包水型乳狀液存在兩種起相反作用的力,一種力一與水珠周圍的乳化劑薄膜有關(guān),即使在水珠碰撞時(shí),它也有阻止水珠合并而形成大水珠的趨勢。另一種力是水珠有相互合并和形成大水珠的相反傾向。較大的水珠會(huì)在重力作用下沉降出來,因而要破壞石油乳狀液,就必須抑制或破壞乳化劑的性質(zhì),使水珠合并。已經(jīng)開發(fā)了許多抵消和破壞乳化劑的方法。1.3.2TheMajorReasonsforDehydratingCrudeOil1.3.2原油脫水的主要原因Theworldwidecrudeoilproductionofabout60millionbpdisaccompaniedbyatleastasmuchwater.Inoldfields,water-oilratiosgreaterthan10arenotuncommon.Therefore,itisnotasurprisethatemulsionformationistheruleratherthantheexception.Thesaltcontentoftheproducedbrinemayrangefrompracticallyzerotoalmostsaturated.Inparticular,dilutebrinesformemulsionswithcrudeoilthatcanbeverydifficulttobreak<i.e.,resolveintoseparateoilandwaterphases>.世界原油產(chǎn)量約為60×106bpd,伴隨而產(chǎn)出的水量至少不低于原油產(chǎn)量。在老油田,水油比超過10者并不罕見?？梢姰a(chǎn)生乳狀液是正常現(xiàn)象,而非特例。產(chǎn)出鹽水的鹽含量圍可能從零至幾乎被鹽飽和。由稀鹽水和原油形成的乳狀液很難破乳〔即很難分離為油、水兩相。Themajorreasonsfordehydratinganddesaltingcrudeoilare:原油脫水脫鹽的主要原因?yàn)椋?lt;1>Crudeoilpurchasersspecifymaximumpermissiblecontentsofsedimentsandwater,S&W,formerlycalledbasicsedimentandwater,BS&.W.Typically,limitsvaryfrom0.1—3wt.:0.1%incoldclimates,0.5%intheGulfcoastandTexas,and3%forlowgravityCaliforniacrude.〔1原油買方規(guī)定了最大允許沉積物和水的含量<S&W>,此含量以前被稱為底部沉積物和水<BS&W>。典型的限定圍為0.1%-3%<質(zhì)量分?jǐn)?shù)>,寒冷地區(qū)為0.1%,<墨西哥>海灣地區(qū)和得克薩斯州為0.5%,加利福尼亞州的低相對密度原油為3%。<2>Crudeoilisboughtandsoldona°APIgravitybasisandhigh-gravityoilscommandhigherprices.Waterlowersthe°APIgravityandreducesthesellingpriceofoil.〔2買賣原油以0API相對密度為基準(zhǔn),0API相對密度高的原油能得到較高的售價(jià)。原油的水降低了0API相對密度,因而降低了原油的售價(jià)。<3>Shippingemulsifiedoilwastescostlytransportationcapacitiesoccupiedbyvaluelesswater<i.e.,S&.W>.〔3由于無用的水占有體積,輸送乳化原油浪費(fèi)了寶貴的輸送能力。<4>Theviscosityofcrudeoilincreasesasthewatercontentisincreased.<Adding1%morewater<orS&-W>typicallyproducesa2%viscosityincreaseina30°APIcrudeanda4%viscosityriseina15°APIcrude.>〔4隨著水含量增加,原油貓度增大。0API相對密度為30的原油多增加1%的水,其黏度一般會(huì)增大2%;0API相對密度為15的原油的黏度約增大4%<5>Mineralsailspresentinoilfieldwaterscorrodeproductionequipment,tankcars,pipelinesandstoragetanks.〔5油田水存在礦物鹽,會(huì)腐蝕生產(chǎn)設(shè)備、鐵路油槽車、管道和儲(chǔ)罐。<6>Refiningofwater-bearingcrudecancauseseverecorrosionandpluggingproblems.Distillationofcrudecontainingwater-borneinorganicsaltscontributestocorrosionandfoulingofrefiningequipment.UndersomecircumstanceschloridescanhydrolyzetoHC1,whichisextremelycorrosive.〔6煉制含水原油會(huì)引起嚴(yán)重的腐蝕和堵塞問題。蒸餾乳化水含無機(jī)鹽類的原油將導(dǎo)致煉制設(shè)備的腐蝕和污垢。在某些環(huán)境下,氯化物會(huì)水解為鹽酸,它的腐蝕性極強(qiáng)。1.3.3TreatingMethods1.3.3處理方法Anymethodofremovingwater,salt,sand,sedimentsandotherimpuritiesfromcrudeoiliscalledoiltreating.Oil-treatingmethodshaveonecommongoal,namely,toprovideasuitableenvironmentforgravitytoseparatethebrinefromthecrude.從原油脫除水、鹽、砂、沉積物和其他雜質(zhì)的任何方法都被稱為原油處理。各種原油處理方法具有共性,即為重力沉降提供良好氛圍,使鹽水從原油分出。Thefollowingarecommontreatingmethods:以下為常用的處理方法:<1>Settlingorprovidinglowvelocity<reducedturbulenceandincreasedresidencetimetoallowfreewatertoseparate>.〔1沉降或提供較低流速〔減少湍流,并增加停留時(shí)間,允許分開游離水。<2>Degassingorseparatingthegasfromtheliquidasitisreleasedintheproductionequipment.Risinggasbubblesseverelyimpedethesettlingofwaterdrops.Manyreportshavedocumentedindetailthebenefitsofdegassingpriortoemulsiontreating.〔2當(dāng)生產(chǎn)設(shè)備產(chǎn)生氣體時(shí),應(yīng)使氣體和液體分離<或稱脫氣>。上升的氣泡會(huì)極力阻止水珠的沉降。許多報(bào)道詳細(xì)證明了在處理乳狀液前脫氣的好處。<3>Chemicaltreatingoraddingemulsionbreakersordemulsifiers.〔3化學(xué)處理或添加破乳劑。<4>Washingorprovidingacontinuous-phasewaterwash.〔4水洗或提供連續(xù)相水洗。<5>Heatingtoreduceoilviscosityandaccelerateseparation.〔5加熱以降低油粘度和并加速分離。<6>Electricaltreating<i.e.,applyingACand/orDCelectricfields>.〔6電處理〔即,使用交流和/或直流電場。<7>Mechanicaltreatingorprovidingincreasedsurfaceareatopromotedropcoalescence.〔7機(jī)械處理或增大水珠的表面積,以促進(jìn)液滴聚結(jié)。Inaddition,fieldtreatingcanaccomplishmisteliminationandremovalofsand,sludge,andothersolids.Ofcourse,successfultreatingimpliesthatthecrudeoilmeetspipelineorrefiningspecifications—usually0.1%~1.0%S&W.Inaddition,thetreatedbrineorproducedwatermustbeessentiallyoil-freetosatisfyenvironmentaldischargeregulations<often15—40ppm>ortopreventreinjectionproblemssuchasscaleformationand/orreservoirplugging.Notethattheoil-in-waterenvironmentalregulationisfarmoreseverethanthewater-in-oiltransport/salesspecification.此外,現(xiàn)場處理能除去液霧、砂、淤泥和其他雜質(zhì)。顯然,對乳狀液的成功處理可使原油滿足管輸或煉制的規(guī)—通常要求沉積物和水的質(zhì)量分?jǐn)?shù)為。0.1%-1.0%。另外,處理后的鹽水或采出水必須基本上不含油以滿足向環(huán)境排放的規(guī)定<常為15--40ppm>,或防止諸如生成水垢和/或堵塞油藏等采出水回注問題。注意:水包油乳狀液的環(huán)境排放規(guī)定比油包水乳狀液的管輸/銷售規(guī)嚴(yán)格得多。1.4OverviewofGas-handlingFacilities1.4氣體處理設(shè)備概論Theobjectiveofagas-handlingfacilityistoseparatenaturalgas,condensate,oroilandwaterfromagas-producingwellandconditionthesefluidsforsalesordisposal.Thisvolumefocusesprimarilyonconditioningnaturalgasforsales.氣體處理設(shè)備用于從氣井井流中分離天然氣、凝析液或油和水,并使這些流體符合銷售或排放的要求。本節(jié)重點(diǎn)討論如何使天然氣的品質(zhì)符合銷售的要求。Fig.1-6isablockdiagramofaproductionfacilitythatisprimarilydesignedtohandlegaswells.Thewellflowstreammayrequireheatingpriortoinitialseparation.Sincemostgaswellsflowathighpressure,achokeisinstalledtocontroltheflow.Whentheflowstreamischoked,thegasexpandsanditstemperaturedecreases.Ifthetemperaturegetslowenough,hydrates<asolidcrystalline-like"ice",matter>willform.Thiscouldleadtoplugging,sothegasmayhavetobeheatedbeforeitcanbechokedtoseparatorpressure.Low-temperatureexchange<LTX>unitsandindirectfiredheatersarecommonlyusedtokeepthewellstreamfrompluggingwithhydrates.圖1-6所示為用于處理氣井氣的生產(chǎn)設(shè)備方框圖。在一級(jí)分離前井流可能需要加熱。由于多數(shù)氣井的壓力很高,故用節(jié)流件來控制氣體流量。氣體節(jié)流時(shí)其體積膨脹,氣體溫度下降。如果節(jié)流后氣體溫度太低,將生成水合物<一種固態(tài)晶體狀的似"冰"物質(zhì)>。由于形成的水合物會(huì)引起堵塞,故氣體節(jié)流至分離壓力前可能需要加熱。低溫?fù)Q熱裝置<LTX>和間接式加熱爐常用于防止井流被水合物堵塞。Gastransmissioncompaniesrequirethatimpuritiesberemovedfromgasthepurchase.Theyrecognizetheneedforremovalfortheefficientoperationoftheirpipelinesandtheircustomersgas-burningequipment.Consequently,contractsforthesaleofgastotransmissioncompaniesalwayscontainprovisionsregardingthequalityofthegasthatis