Branschordlista Absorptionsabsorption är förmågan hos vätskor och fasta ämnen att suga upp vatten eller andra vätskor, inklusive oönskade gaser, vid naturgasbehandling. Access Access är ett system under vilka marknadsaktörer får använda kapacitet i en rörledning, ett nätverk, ett gaslager eller en annan gasanläggning. Tillträde är centralt för genomförandet av liberaliseringen av gasmarknaden och kontraster, därför med den traditionella modellen där ägare till transportsystem, butiker mm äger all gas som flyter genom sin utrustning och fungerar som exklusiva handlare för den. Se även Gemensam transport. Begränsad åtkomst . Förhandlad tillgång. Tredjeparts åtkomst. Acid Gas Acid Gas är naturgas som innehåller en andel av gaser som koldioxid eller vätesulfid, som i kombination med fukt bildar sura föreningar. Årlig kontraktsmängd Den årliga kontraktsmängden (ACQ) är den mängd gas som Säljaren måste leverera och köparen måste ta ett visst kontraktår. Det kan uttryckas som ett diskret nummer eller som ett flertal av den dagliga kontraktsmängden. I praktiken skrivs många kontrakt i blanketter som gör att köparen kan ta betydligt under den angivna ACQ. Se även Nedåtgående Mängd Tolerans. Årligt leveransprogram Det årliga leveransprogrammet (ADP) är ett schema över gasvolymer som ska levereras på vissa datum eller inom vissa perioder under ett kommande kontraktsår i ett långsiktigt kontrakt. I praktiken kommer detta ofta att ske i form av ett detaljerat schema som täcker de första månaderna, med lossare siffror under resten av året som sedan stärks upp ibland i kontraktet. Aquifer En Aquifer är en kropp med porös sten mättad med vatten. Gasfält är vanligtvis underlag av en vattenförekomst som ofta ger tryck som kallas Water Drive för att hjälpa till med gasproduktionen. Underjordisk lagring av gas kan uppnås genom att pumpa gas ner i vattenförekomster under ogenomträngliga kappstensar och därmed effektivt göra en gasreservoar. Se även Reservoar. Underjordisk förvaring. Arbitrage Arbitrage köper och säljer samma produkt på två olika platser eller marknader för att dra fördel av prisskillnader. Associerad gasrelaterad gas är gas som sameksisterar med olja i ett övervägande oljefält. Det kan vara Cap Gas eller Solution Gas. beteende och behandling av vilka är olika. Associerad gas kommer normalt att säljas som säljarens nomineringsgas, dvs säljaren nominerar de tillgängliga gasmängderna. På traditionella gasmarknader skulle en sådan gas leda ett lägre pris än icke-associerad gas. Autogeneration Autogeneration är elproduktionen genom en industriell angelägenhet, främst för att möta behoven hos sin egen verksamhet. Se även Kombinerad värme och kraft. Backhauling Backhauling är transporten av gas uppenbarligen i omvänd riktning till rörledningens huvudflöde. Detta uppnås vanligen genom bytesarrangemang snarare än genom fysiska rörelser. Känd även som Reverse Flow. Balansavtalsbalansavtal används för att definiera förfaranden för kapacitetsutnyttjande i rörledningar eller produktion från ett gasfält: 1) Rörledningar: Ett balanseringsavtal för en rörledning är ett avtal mellan en rörledningsejer och andra användare av rörledningen om förfarandet för att antas för att säkerställa att gasvolymerna som matas till och tas bort från rörledningen är lika över en viss tidsperiod. Rörledningar kräver vanligen daglig balansering, men vissa kräver balansering över kortare perioder, till en timme, speciellt där det finns en kraftig kraftproduktionsbelastning på rörledningen. Andra kan tillåta längre perioder, t. ex. 3 dagar upp till månad. Månadsbalansering är endast lämplig där tredjepartsbelastningar är mycket små (några procent) i förhållande till huvudanvändarna. 2) Reserver: Ett balansavtal för reserver är ett avtal mellan ägarna till ett gasfält som marknadsför sina andelar av gasen oberoende av varandra. Eftersom varje köpare kan ha ett annat efterfrågemönster, är ägarna överens om att de inte kommer att dra tillbaka reserverna med en hastighet som kommer att orsaka obalans i ägande av de återstående reserverna överstiger vissa överenskomna toleranser. Avtalet definierar också vilka åtgärder som ska vidtas om dessa toleranser överskrids. Syftet är att säkerställa att ägarandelen i de återstående reserverna är konstant för alla praktiska ändamål. Basbelastning Basbelastningen är leveransgraden (eller efterfrågan) under vilken utdelning (eller efterfrågan) inte förväntas falla under en given period. Strandpris Strandpriset är en term som huvudsakligen används i Förenade kungariket för att definiera det pris på vilket offshore gas överförs av producenten vid utgången från anläggningen på land, varav ägandet överförs före vidare överföring eller användning. Brännugn Gas Gas producerad som en biprodukt från användning av koks i traditionella masugnar. Denna gas var av lågt kalorivärde (ungefär kvart till en tredjedel av naturgas) men användes blandat med tillverkad gas i dagarna före naturgas. Block A-block är ett geografiskt område som definieras i ett koncessionsavtal, ofta prefixat av Exploration, Development eller Production. Ofta definierad med avseende på latitud och longitud, men kan också definieras med hänvisning till ett lokalt rutnät, till exempel i Mexikanska golfen. Nedblåsning En metod för att tillverka en gasondensatbehållare genom att låta reservoartrycket falla som gas produceras över tid utan att injicera någon annan gas. Med denna produktionsmetod kan kondensat kondensera i behållaren, där återhämtningen inte längre är ett praktiskt förslag. Koka av gas (BOG) Koka av är en term som används i LNG-projekt. Emellertid kan väl isolerade LNG-lagertankar vara, LNG är alltid vid sin kokpunkt, och små mängder fortsätter att koka bort. I flytande växter krävs en liten mängd koksuggas för att säkerställa att anläggningsflaren är i drift. Kokning som inte behövs för detta ändamål kommer normalt att användas i anläggningens egna lågtrycksbränslesystem. På LNG-tankfartyg som drivs av ångturbiner används gasen normalt som bränsle för att köra fartygen. Gränsvärde Priset vid vilket gas säljs vid gränsen mellan två länder. Typiskt baserat på tull eller annan officiell importexportdata. Ofta används, särskilt i Europa, som en referenspunkt i gasavtal. Gasflaska med flaska. vanligtvis butan eller propan lagras i flytande tillstånd vid måttligt tryck i stålbehållare för användning i små bostäder och kommersiella applikationer. Bundled Tillhandahållande av olika tjänster, såsom transport, lagring etc. i en obligatorisk paket som köparen måste acceptera totalt, utan att kunna välja vilka delar det kräver. Se även Unbundling. Butan En medlem av alkankruppen av kolväten med fyra kolatomer i sin molekyl (C4H10, ofta förkortad till C4 vid icke teknisk användning). Butan är en färglös, brandfarlig gas vid normal temperatur och tryck men är lätt att kondensera genom tryck för lagring och transport. Det finns två isomera former, normal och iso-butan. Vid atmosfärstryck kondenseras isobutan vid 1200 ° C och normalt butan vid -100 ° C. Kalorivärde (CV) Kalorivärde är den mängd värme som produceras genom fullständig förbränning av ett bränsle. Detta kan mätas torr eller mättad med vattenånga och netto eller brutto. Se även Bruttokaloriskt värde. Nettokaloriskt värde. Cap 1. En klausul i ett leveranskontrakt enligt vilket köparen är säker på att han inte behöver betala mer än ett givet maximipris. Denna typ av kontrakt är analog med ett köpoption. 2. I ett Leveransavtal där köparen har flexibilitet i den volym som den kan begära, det maximala som det har rätt till antingen över en period (t ex ett år) eller under kontraktets löptid. Cap Gas Gas finns i en Gas Cap i förening med olja men inte förenade med den. Kapacitetsavgift En kapacitetsavgift är betalningen för reservkapacitet i en rörledning, en gasaffär eller annan infrastruktur. Används ofta omväxlande med efterfrågan. Kapacitetshandel Att köpa och sälja förvärvade rättigheter att flytta gas genom en Transporters rörledningar. Kolsekvestmentering och lagring Fångst av koldioxidutsläpp till atmosfären och lagring i kolsänkor, vilken kamera är naturlig eller kan vara utarmade kolvätenfält. Carbon Trading Ett systematiskt förfarande för utbyte av tillstånd för att producera koldioxidutsläpp. Se EU ETS. Vidarebefordran En avsättning inom ett långsiktigt Take - eller Pay Contract enligt vilket en Köpare som tar mer än sin årliga Kontraktskvantitet under ett år är tillåtet att på villkor som anges i kontraktet motverka detta mot åtaganden under senare år som annars skulle ha uppkommit någon form av sanktion, som ta eller betala. Ibland känd som Advance Make Good. Casing Head Petroleum Spirit (CHPS) Ett alternativt namn för kondensat och speciellt för de som släpper ut vid eller nära brunnshuvudet. Används huvudsakligen i Nordamerika. Churning Churning är en term som används i gashandel för att ange hur många gånger i genomsnitt den gasen handlas mellan första försäljningen och den slutliga konsumtionen. City Gas City-gas är en term som används i vissa delar av världen, till exempel Egypten, Indien, Japan, Korea, för att hänvisa till gas som distribueras till kunder via ett lokalt distributionssystem, nedströms City Gate. Sådana kunder kommer att vara en blandning av bostäder, kommersiella och industriella beroende på speciella lokala förhållanden men kommer vanligtvis att utesluta kraftgeneratorer. I den förflutna staden kan gas ha varit gas tillverkad av kol och olja men är nu övervägande naturgas. Se även Stadsgas. City Gate Den punkt där ett lokalt distributionssystem, som ofta bygger på en stad eller stad, accepterar gas från ett överföringsföretag eller system. Ett överföringspris på denna punkt kallas ett City Gate-pris. Koldbäddsmetan (CBM) Koldbäddsmetan är metan som är eller kan återvinnas från kolsömmar. Kallas även kolsömgas. CBM återvinns genom borrning av brunnar i lämpliga kolsömmar och reducerar sedan trycket i berget, vanligen genom att pumpa ut vatten, vilket kan vara saltlösning och uppvisa miljöproblem, tills metan kan desorberas från kolet. CBM, till skillnad från konventionell naturgas, är inte instängd under en försegling men adsorberas i kolet. Det kan därför uppstå i kolavsättningar som är sidledigt mycket omfattande. Produktionshastigheten är typiskt mycket mindre än för konventionell gas. Utsläppshastigheter är vanligtvis ganska långsamma och brunnar kan producera i många år. CBM kan också produceras som en säkerhetsåtgärd innan kol minskar för att minska förekomsten av potentiellt explosiva gasblandningar under gruvdrift. Se kolgruvmetan. Kolgasgasgas är gas som tillverkas genom destruktiv destillation av bituminöst kol. Huvudkomponenterna är väte (mer än 50), metan (10-30) kolmonoxid och högre kolväten. Vattendampen i kolgas håller gamla rörledningar täta, vilket minimerar förlusten av gas. Om naturgas införs i samma rör utan korrigerande åtgärder kan stora förluster uppstå. Kolmonoxiden är givetvis giftig. Inhalering av kolgas var ett föredraget sätt att begå självmord i städer med kolgasfördelning. Koldioxidmetan (CMM) Metan återvinns från kolgruvor, antingen under aktiv eller efter övergivande, som kan användas i lokal kraftproduktion eller värmeproduktion. Det är sällan tillgängligt i tillräcklig mängd för att motivera bearbetning till rörledningskvalitet för leverans till ett rörledningssystem. Se: Kolbäddsmetan. Koksugnsgas Koksugnsgas produceras som en biprodukt av koksning av kol och var samtidigt en huvudbeståndsdel av tillverkad gas. Kombinerade cykeldurgsturbin En kombinerad cykeldurgsturbin (CCGT) är en typ av elproduktionsanläggning där värmen från förbränning av gaserna används två gånger. Först bränns gasen för att driva en gasturbin. Sedan passerar de heta avgaserna genom en värmeväxlare för att höja ånga för en sekundär ångturbinenhet. Kombinerade cykelväxter har en värmeeffektivitet ca 50 större än en vanlig enkel eller öppen turbin. Kombinerad värme och kraft (CHP) kombinerad värme och kraft (CHP) är användningen av ett enda enhetligt system för att leverera både värme och kraftbehov i ett projekt, vilket minimerar värmeavfallet. Effekten produceras genom gasturbiner eller annan huvudmotor. Avgasvärmen utnyttjas för andra krav än elproduktion. Känd som kogeneration och total energi. Varubeskrivning Tidsavgift för en avgift för varje gasenhet som faktiskt tas eller transporteras. Kan vara i volymetrisk eller värmeenheter. Skiljer sig från stående laddning och efterfrågan. Common Carriage Common Carriage är en term som ofta används utbytbart med Open Access och Third Party Access men som faktiskt är mer specifik. I ett gemensamt transportsystem ges alla sökande till kapacitet (t. ex. i rörledning eller butik) tillgång på lika villkor. Om den begärda totala volymen överstiger tillgänglig kapacitet minskas användningen av alla parter pro rata: kapacitet ransoneras bland användare. Under öppen åtkomst, om sökandena söker mer kapacitet än vad som är tillgängligt, fördelas kapaciteten på först till kvarn eller ett betal-till-boksystem som gör att kapaciteten kan kontraheras och handlas precis som att hyra och sublätta utrymme i en byggnad . En pipeline - eller butiksejer som också vill använda sig av en viss kapacitet måste, enligt Open Access, göra det via en arvslängdsaffär, vars kommersiella relationer med kapacitetsleverantören är transparenta identiska med andra användares. Open Access krävs på amerikanska interstate rörledningar, där det kallas kontraktstransporter. I Europa används termen Open Access ibland löst som synonymt med tredjepartsåtkomst, för att definiera tredje parts rätt att använda rörledning eller utrustning från ett annat företag. I sin allmänna form omfattar den öppen åtkomst, gemensam transport, förhandlad tillgång och reglerad åtkomst. En aspekt av tredjepartstillträde är att det inte i sig innebär någon lösning på diskrimineringsfrågan mellan parterna med hjälp av anläggningarna. Se även Begränsad åtkomst. Komprimerad naturgas (CNG) CNG är naturgas komprimerad i gasflaskor, främst används som alternativ för flytande bränslen i vägfordon. CNG förblir en gas oberoende av trycket. För att inte förväxlas med flytande petroleumgas. Kompressor Station Gas förlorar tryck eftersom den färdas långa sträckor genom ledningar. För att säkerställa ett jämnt flöde och ett tillräckligt tryck vid borttagningsstället måste det komprimeras på kompressorstationer, som vanligen ligger 60 km till 100 km längs landtransportledningarna. Offshore och i avlägsna områden kan det vara bekvämt och föredraget att upprätthålla högre tryck och tillåta större avstånd mellan kompressorstationerna. På stora rörledningar drivs kompressorer normalt av gasturbiner. Mindre rörledningar får använda dieselmotorer. Koncession En licens utfärdad antingen av ett statligt eller statligt oljebolag. Det definierar ett område, ofta kallat ett block. beviljats ett företag eller en grupp av företag för prospektering, produktion eller transport av olja och gas under specificerade villkor och under en bestämd period. Koncessionsområden är ofta initialt tilldelade för prospektering. Om detta lyckas så definieras ett mindre område, inom prospekteringsblocket, som ett produktionsblock. Kan också tillämpas på tillstånd att bygga rörledningar, kraftverk etc. Kondensatkondensat är en naturgasvätska med lågt ångtryck, producerat från en behållare med högt tryck och temperatur. Kondensat separeras naturligt i en ledning eller separationsanläggning genom den normala kondensationsprocessen. Kan hänvisa till en blandning av relativt lätta kolväten som förblir flytande vid normal temperatur och tryck. Det kommer att bli lite propan och butan upplöst i den. Till skillnad från råolja. den innehåller lite eller ingen av de tunga kolväten som utgör tung eldningsolja. Det finns tre huvudkällor för kondensat: a) De flytande kolvätena som produceras från en gasbaserad reservoar. Dessa kan endast vara litet urskiljbara från en lätt stabiliserad råolja. b) De flytande kolvätena som återvinns vid ytan från icke-associerad gas. c) De flytande kolvätena som separeras när rå gas behandlas. Detta kondensat består typiskt av C5 till C8. Kondenspanna En kondensatpanna är en vattenuppvärmningsanordning avsedd för ökad effektivitet genom att använda rökgaser som annars ventileras till atmosfären för att förvärma vatten i pannan. Anslutningsavgift Ibland används som en synonym för Stående Avgift men mer korrekt definierad som ett belopp som ska betalas av kunden i en enstaka summa eller avbetalningar för anslutning till leverantörssystemet. Entreprenör En term som har en särskild betydelse i ett produktionsdelsavtal. Entreprenören är företaget (vanligtvis ett producerande företag) som åtar sig att utforska andor producera för värdregeringen i stället för definierade volymer av den producerade gasen eller oljan. Konvergens En löst definierad term som avser ökad användning av naturgas vid elproduktion. När generationen blir helt eller i stor utsträckning beroende av naturgas, samlas gasleverantörens och kraftgeneratorens intressen och möjligheten att växla gas mellan generation och direkttillförsel, beroende på det tillgängliga priset för varje utlopp. Priserna konvergerar när det inte finns någon fördel vid bytet. Kostnad Gas Kostnadsgas är den gas som en Entreprenör förvärvar enligt ett produktionsavtal för att täcka kostnaderna för sin verksamhet enligt kontraktet. Kontraktören arbetar normalt på egen risk och om inga kolväten upptäcks är kostnaderna helt för sitt konto. Se även vinstgas. Kritiskt tryck Det minsta trycket som måste appliceras på en gas innan det kan kondenseras. Kritisk temperatur Den temperatur över vilken en gas inte kommer att flyta, oavsett vilket tryck som appliceras. Råolja En blandning av kolväten som finns som en vätska i naturliga underjordiska reservoar och förblir flytande vid atmosfärstryck efter att ha passerat ytskillande anläggningar. Råmaterial är råmaterialet som förädlas till bensin, värmeolja, jetbränsle, propan, petrokemikalier och andra produkter. Kryogenik Processen att producera, bibehålla och använda mycket låga temperaturer (under -46C - 50F). Relevant i LNG-verksamheten. Kuddegaskudde Gas är kvar i en gasbutik för att ge det tryck som behövs för att producera lagrad gas, men som förblir oproducerad. Det är typiskt av storleksordningen 50 av den totala lagrade volymen för en Aquifer och utarmad fält, men mindre för andra typer av lagring. När butiken ursprungligen etableras Kuddegas, om det inte är oproducerade reserver kvar i ett delvis utarmat fält, kan det vara en stor del av kapitalkostnaden. Kuddegas kan slutligen användas när butiken avvecklas. Även känd som basgas. Daglig genomsnittlig utdelning Total volym gas levererad under en tidsperiod dividerat med det totala antalet dagar under perioden. Daglig kontraktsmängd (DCQ) Den mängd gas som en köpare nominellt åtar sig att köpa och en säljare åtar sig att leverera inom en definierad 24-timmarsperiod. Trots att det finns många kontrakter, är detta uttryck i praktiken av liten betydelse i sig. Det kan fungera som ett sätt att uttrycka årlig kontraktsmängd om den senare uttrycks som ett antal dagar multiplicerat med DCQ. Det kan också definiera den ränta vid vilken säljaren måste kunna leverera gas. Se även: Daglig leveranssats. Daglig leveranssats Daglig leveranssats (DDR) är den takt som säljarens anläggningar måste kunna leverera gas, uttryckt som en volym gas per dag, eller som ett flertal av den dagliga kontraktsmängden. Även känd som den maximala dagliga kvantiteten. Daglig Peak Daily Peak är den maximala volymen av gas som kan eller måste levereras begärs någon dag under en given period (vanligtvis ett år). Dedikationsavtal Ett Dedikationsavtal är den rätta termen för ett avvecklingsavtal. under vilken hela produktionen från ett gasfält köps och säljs. Examensdag En examensdag är ett mått på medeltemperaturen över en dag och är vanligtvis relaterad till en temperaturgräns. Till exempel är en verklig genomsnittstemperatur på 5C på en dag 2 grader dagar varmare än en förväntad genomsnittstemperatur på 3C. Kan också användas för att mäta kumulativt kallt väder under en period. Således om säsongsmässig normal temperatur för en månad är 18C och den genomsnittliga faktiska temperaturen under månaden förväntas bli 8C, kommer månaden att vara 10 x 30 300 grader dagar kallare än normalt. Levereras En term som huvudsakligen används i LNG-fraktkontrakt för ett arrangemang enligt vilket säljaren är ansvarig för att ordna och betala för frakt av gasen och titeln passerar i leveranshamnen. Vanligtvis är säljarnas risker större i en levererad transaktion, eftersom köparen bara betalar för den landade kvalitetskvoten och Boil Off Gas är säljarens ansvar. Säljaren ansvarar för röjning genom tull och betalning av alla avgifter om inte annat anges i avtalet. Ett alternativt namn för ett Levererat kontrakt är Ex Ship. Mycket liknande levereras är kostnad, försäkring och frakt (CIF). Detta är ett arrangemang enligt vilket säljaren arrangerar och betalar för frakt och försäkring, som för levererat kontrakt, men risk och titel överförs från säljaren till köparen på ett sätt som definieras i avtalet (t. ex. vid leverans eller vid leverans av konteringsbrev till köparen). CIF och Delivered är ofta men felaktigt behandlade som om de var identiska eftersom kostnaderna för säljaren är desamma. Enligt en CIF-kontrakt kan säljaren dock undvika att vara i besittning av lasten inom jurisdiktionen hos köparlandsstyrelsen. Detta kan vara viktigt för skattemässiga eller juridiska skäl. Det tredje arrangemanget som ofta träffas vid leverans av LNG är Free Board, (FOB), som används för att beteckna leveranser där köparen arrangerar leverans och leverans och titelförändring vid lasten laddas in i skepp vid lastporten. Efterfrågningsavgift En månadsavgift eller årlig avgift betald av en köpare för en nominerad, reserverad topp eller för den faktiska högsta volymen av gas som tas på en timme eller dag under en given period. Således kan ett typiskt uttryck vara dollar per tusen kubikfot av högsta timmars kapacitet per månad. Ofta används utbytbart med Kapacitetsavgift, även om det kan hävdas att i strikt logik bör efterfrågningsavgift gälla för en gasförsäljning och kapacitetsavgift till ett transportarrangemang. Avfallskontrakt Ett uttagsavtal är ett produktionsförsäljningskontrakt där försäljningsvolymerna i huvudsak styrs av prestandaegenskaperna hos det specifika gasfältet. Ett uppbyggnadsmönster, en förväntad platå och en metod för att bestämma nedgångsmängder definieras initialt men kan ändras eftersom fältets produktionsförmåga bättre förstås genom operativ erfarenhet. Köparen förutsätter sålunda en stor andel av produktionsriskerna. Se även Dedication Contract och Supply Contract. Depot Drive Reservoir En gasreservoar från vilken gas återvinns genom expansion då gastrycket faller med produktion av gas som ursprungligen är på plats. Reservoaren kan därför behandlas som om den var en sluten tank. Återvinningsfaktorer på upp till 90 av gasen på plats kan uppnås. I sådana reservoarer finns det ingen vattendrift. Deregulering Deregulation är minskningen av rollen som tillsynsorgan som oftast förknippas med en ökning av öppen konkurrens och uppnås genom förenkling av regelverket. Deregulation bör inte förväxlas med liberalisering, vilket kan kräva införande av transparenta regleringsförfaranden. Derivat Derivat är finansiella instrument som i sista hand bygger på handel med en fysisk vara, inklusive gas och andra former av energi. Se även Futures. Swappar. Duggpunkt De temperaturer under vilka kolväten (kolväte daggpunkt) eller vatten (vatten daggpunkt) börjar kondensera ur en given gasflöde. Kondensering minskar noggrannheten i mätningen och skapar olägenheter hos flytande sniglar i rörledningar, vilket måste rensas regelbundet genom att passera en gris men rörledningen. Dessutom kan vatten reagera med koldioxid eller vätesulfid i gasflödet för att bilda syror och med metan i sig under lämpliga betingelser för att bilda hydrater. Därför avlägsnas normalt i behandlingssteget vatten från gasflödet för att minska duggpunkten till någonstans runt -10 ° C vid standardrörledningstryck. Distribution Den sista fasen i transporten av gas (och el) och dess försäljning till slutkonsumenter genom medelstora rörledningar och lågtryck med liten diameter. Retikuleringsnät. Daglig lagring Bokstavligen, daglig lagring. Kortsiktiga eller topplagring av gas i rörledningar eller gashållare, för att möta lokala, dagliga fluktuationer i efterfrågan, i motsats till säsongsförvaring. Mångfaldsfaktor Förhållandet mellan summan av individuella maximala krav från flera konsumenter eller laster, till deras samtidiga maximala efterfrågan. Vanligtvis mindre än 1 för att avspegla att inte alla kunder förväntas ta sitt maximala krav samtidigt. Se även Lastfaktor. Nedströms Dessa aktiviteter i gaskedjan närmast slutkunder. Se uppströms. Nedåtgående kvantitet Tolerans (DQT) Den nedåtgående kvantitetstoleransen (DQT) är det belopp som en köpare kan förkorta sin fulla årliga kontraktskvantitet i ett Take or Pay gas-försäljningskontrakt utan att påföra sanktioner. Om det inte finns någon bestämmelse som kräver att köparen ska ta kompletterande volymer i efterföljande år för att klara sig för bristen, blir den årliga kontraktsmängden i kraft ACQ minus DQT. Se också Gör gott och smink. Torrgas Ett alternativt namn för Lean Gas. Det betyder inte utan vatten, men i vissa fall kan det vara. Torrt gasfält En behållare som ger torrledgas och mycket små mängder kondensat, vanligtvis mindre än 10 fat per miljon kubikfot. Detta motsvarar 350 barrelsMMcm eller 60 kubikmeter oljeMMcm gas som antar 0,159 barrelscubic meter. Torrhål Ett borehål som inte kan producera kommersiella volymer av olja eller gas. Konceptet är välbegränsat till ett borehål som kan producera olja eller gas. EFET European Federation of Energy Traders. En tryckgrupp av europeiska handelsföretag för energi som syftar till att stimulera och främja handel med energi. Effektivitetseffektivitet, eller värmeeffektivitet, är förhållandet mellan energiproduktion och energiinmatning i en process. En av de vanligaste användningsområdena för detta förhållande inom gasindustrin är användningen av gas för kraftproduktion där elförmedlingen uttrycks som en procentandel av den förbrukade gasen, mätt på basis av en gemensam enhet, t. ex. kWh. Försiktighet måste vidtas för att skilja mellan netto och brutto effektivitet. Se även Bruttokaloriskt värde. Nettokaloriskt värde. Slutanvändare Konsumenten av gas, i bostads-, kommersiell eller industriell sektor. Den sista spelaren i gaskedjan. Entry-Exit Ett inträde-avgångssystem är ett där en gasförare laddas med ett inmatningspris för att sätta gas i ett överförings - eller distributionsnät vid en bestämd ingångspunkt och ett utgångspris för att avlägsna gasen vid en bestämd utgångspunkt. Priserna kan återspegla trafikstockningar vid in - och utgångspunkter, men är desamma för alla användare. Systemet kan vara kontrasterat med punkt-till-punkt-system, där transportkostnader beror på det faktiska eller teoretiska avståndet som reser av varje försändelse av gas. Entry-Exit är starkt gynnad av EU som ett medel för att främja gasliberalisering. ERGEG Den europeiska tillsynsmyndigheten för el och gas. ERGEG är Europeiska kommissionens formella rådgivande grupp av energiregulatorer. ERGEG grundades av Europeiska kommissionen i november 2003 för att hjälpa kommissionen att skapa en gemensam marknad för el och gas. ERGEGs medlemmar är cheferna för de nationella energimyndigheterna i EU: s medlemsstater. Etanetan (C2H6, ofta förkortad till C2 vid icke teknisk användning) är ett av de viktigaste beståndsdelarna i naturgas tillsammans med metan. Koka vid -84,4C. Vid normala temperaturer är det en torr, färglös och luktfri gas. Ett råmaterial för etenproduktion. Etylen Även känd som eten. En färglös gas (C2H4) framställd genom sprickning av kolväten, såsom etan eller nafta, och som används som råmaterial för petrokemikalier, såsom fibrer och många plastmaterial. Kokar vid -103,7C. EU ETS Europeiska unionens emissionshandelssystem. Det största multinationella systemet för handel med utsläppsrätter i världen och en viktig pelare för EU: s klimatpolitik. Överskott av gas överskattad gas är antingen: a) Gas tas till en hastighet som överstiger den dagliga leveranssatsen till ett premiepris eller b) Gas som tas över det årliga kontraktet. Beroende på villkoren i kontraktet och leveransstatus kan sådan gas kvalificera sig som Carry Forward. Gör bra eller sminkgas. Federal Energy Regulatory Commission (FERC) En amerikansk federal myndighet vars ansvar innefattar att reglera interstate gasindustrin. Har ingen jurisdiktion över gasledning och leverans där handeln är helt inom enskilda stater. Kolväten som används som råmaterial i en industriell process, inte som bränsle. De huvudsakliga användningarna av naturgas som råmaterial är vid tillverkning av ammoniak och ammoniakbaserade gödningsmedel och metanol. En potentiell stor marknad är användningen av gas för att göra syntetiska oljeprodukter såsom motorbensin och mellandestillat (se gas till vätska). Kan också användas för att beteckna det råmaterial som används för att producera el, men statistiska sammanfattningar av gasförbrukningen skiljer normalt denna användning från användningen av kemiska råvaror. Se även Middle Distillate Synthesis. Fältbedömning Processen att kvantifiera reservnivåer och produktionspotential hos en nyupptäckt petroleum (olja och gas) reservoar, vanligtvis genom borrning av en eller flera avgränsnings - eller bedömningsbrunnar. Fast gasgas som en leverantör åtar sig att leverera till en köpare enligt villkor som anges i kontraktet, utan avbrott. Se även: Avbrytbar gas. Fischer-Tropsch Process En kemisk process för att omvandla syntesgas till paraffiner genom polymerisation. Ursprungligen utvecklat i början av 1900-talet för att göra bensin från kol. Nyare forskning har identifierat katalysatorer som kraftigt ökar processens effektivitet genom att skapa väldigt långa vaxartade produkter, som sedan kan omvandlas till mycket högkvalitativa flytande bränslen genom konventionell sprickbildning. Se mellandestillatsyntesen. Brännbarhetsgränser Minsta och maximala procentsatser av gas i luft inom vilken gasen kommer att antändas. För naturgas ligger dessa gränser ungefär mellan 5 och 15. Flaring Processen för att bränna oönskad naturgas eller olja. In the case of gas, usually occurs when it is associated with oil and cannot be economically exploited or re-injected. Now less prevalent, as governments seek to profit from the increased value of gas and reduce the advert environmental impact of burning hudrocarbons. Floating LNG Floating LNG (FLNG) is the use of purpose built or converted ships to enable regasification of LNG (and liquefaction) to be carried out offshore. FLNG has the advantage that LNG production and importation can start more quickly than could happen onshore, where lead times are often lengthened by the local approval process. It also enables the processes to move location to satisfy short term demand. Force Majeure A contractual term used to define circumstances in which a party to a contract is not obliged to carry out its obligations because of major events outside its control. Force Majeure can mean very different things, depending upon the law under which the contract is written and the provisions of the clause, which can vary widely. Examples of force majeure could be war, extreme weather, industrial action. Forward Trading Buying and selling gas (and other commodities) to be delivered at a later date, not under a long term contract. See Futures . Fuel Cell Equipment used to generate electric energy directly from the reaction of hydrogen and oxygen in the presence of a catalyst, without combustion. Natural gas can be used as a feedstock from which to obtain the hydrogen. Carbon dioxide will then be produced in the reformation process. Fuel Gas Gaseous fuels, in particular low pressure natural gas used to fuel production or treatment facilities. Futures A future is a contract to buy or sell a specified quantity of gas (or any other commodity) for a specified price on a pre-arranged date. The contract is usually of standard form and can itself be traded at an exchange such as NYMEX or the IPE . Gas:Oil Ratio . The gas:oil ratio is the relationship between the volume of gas produced at atmospheric pressure and the volume of oil produced in a given field. This volume will normally vary considerably over the life of the field. May be expressed as a simple volumetric ratio e. g. 500:1 or as cu ftBarrel. See also Solution Gas. Gas and Electricity Markets Authority (GEMA) The body which determines strategy and takes major policy decisions for Great Britains gas and electricity regulation. Day to day management of policy, resources and operational issues is carried out by the Office of Gas and Electricity Markets ( OFGEM ). Gas Cap In a field where oil is saturated with gas, so that it can dissolve no more, some gas will collect at the top of the reservoir, where it is known as cap gas, and forms a gas cap. Cap Gas overlies the oil and thus provides additional pressure for oil production, but will therefore often be produced only after all the oil has been produced and will then be treated as Non Associated Gas . Unlike Solution Gas . it is not commingled with the oil. Gas Condensate Field A field consisting of one or more reservoirs containing a mixture of gases at reservoir temperature and pressure, but which at normal temperature and pressure separates out into natural gas and Condensates . A gas condensate field is richer in liquids than a Dry Gas field but there is no precise point at which one becomes the other. Sometimes a reservoir will be produced primarily to obtain the condensate the gas may be re-injected, used as a secondary product, e. g. for LNG production or, particularly in areas remote from the market, flared. The liquid in a gas condensate field is often more valuable than the gas. See also Gas Cycling . Gas Condensate Ratio The ratio of gas to condensate in a gascondensate reservoir, usually expressed in practice as the ratio of Condensate to gas. Typical units are barrels of condensate per million cubic feet of gas. Gas Cycling or Re-Cycling A process in which produced gas is re-injected into the reservoir after removal of the condensate. This is to maintain the reservoir pressure and prevent Condensate from condensing in the reservoir and then becoming difficult to recover. This contrasts with Blowing Down the gas condensate field. Gas Day A period of 24 hours starting and ending at a stated time (often 0600 hours). Gas Detector An instrument used to detect the presence of various gases, often as a safety precaution to guard against leakage of flammable or toxic gases. Gas Gathering System A gas gathering system is a network of pipelines from a number of fields, collecting gas and bringing it to a central point, often a processing system or the inlet to a major transportation pipeline. Sometimes built where individual fields are not big enough to justify investment in separate pipelines and processing plant. Gas Grid A gas grid or network is a connected set of pipelines for the transmission and distribution of gas in a region or country to industrial, commercial and domestic users. See Reticulation. Gas Holder Over ground structure used to hold gas for within-day Peak Shaving purposes in urban areas. Gas holders are relics of the manufactured gas era and are steadily disappearing, their function being largely usurped by Line Pack. Gas Lift Injection of gas into an oil reservoir in order to mix gas with oil, reduce the fluid density and so assist oil flow. Gas Marketer A company that supplies gas to end users. See also Shippers . and Local Distribution Companies . Marketers are also major users of transportation capacity. Gas Processing The separation of oil and gas, and the removal of impurities and natural gas liquids from natural gas to meet the delivery Specification of a gas transportation pipeline. Gas Supplier A company that sells gas to the end consumer (UK). Gas to Liquid Gas to Liquid GTL processes convert natural gas into Synthetic Gasoline or Middle Distillates . using the Fischer Tropsch synthesis method. Increasingly relevant where gas is found in fields remote from markets such that delivery by pipeline is likely to be uneconomic. Gas Turbine A turbine propelled by the expansion of compressed air, heated by the combustion of a fuel such as natural gas or gas oil. Widely used for power generation. See Combined Cycle Gas Turbine. Gas Well A borehole sunk into the ground with the objective of bringing natural gas to the surface. GNL The French language acronym for LNG . stands for Gaz Natural Liquifi. Greenfield Often used to refer to a planned development which must be built from scratch on a new site, hence green field, without existing infrastructure. Gross Calorific Value (GCV) The heat generated by the complete combustion of a unit volume of gas in oxygen, including the heat which would be recovered by condensing the water vapour formed. The preferred value for expressing gas calorific quality in gas contracts. Also known as Gross Heating Value, Higher Calorific Value (HCV) or Higher Heating Value (HHV). See also Net Calorific Value. Heads of Agreement A non-binding statement of the main elements of a proposed agreement. See Memorandum of Intent (MOI). Heel LNG LNG left in ship and shore storage tanks to maintain their cryogenic temperatures. Henry Hub Henry Hub is the largest centralized point for natural gas spot and futures trading in the United States. The New York Mercantile Exchange (NYMEX) uses Henry Hub as the notional point of delivery for its natural gas futures contract. NYMEX deliveries at Henry Hub are treated in the same way as cash-market transactions. Many natural gas marketers also use Henry Hub as their physical contract delivery point or their price benchmark for spot trades of natural gas. Henry Hub is owned and operated by Sabine Pipe Line, LLC, which is a wholly owned subsidiary of ChevronTexaco. Henry Hub is based on the physical interconnection of nine interstate and four intrastate pipelines in Louisiana. Hexane A colourless gas (C9H14) naturally occurring in gas fields and normally left as part of the Condensate stream after separation. Boils at -69C. High Sulphur Fuel Oil (HSFO) The bottom of the oil barrel. The lowest priced oil product now, for environmental reasons, often banned or only allowed to be used where rigorous control of emissions is practiced. In some countries with developing gas-to-oil competition it may represent the marker for power station fuel. Hourly Peak The maximum volume of gas delivered or demanded in any one hour during a given period (usually 24 hours). Hub A term, met most frequently in the U. S. but also now used in Europe, for a geographical point at which several pipelines meet, storage is often available, and opportunities for gas trading can be exploited. There are many hubs in the U. S. of which the most important is Henry Hub . In Europe the largest hub is the National Balancing Point in the UK. Hydrates Ice-like solids in which methane molecules are held within the molecular spaces of the water molecule. Can form in pipelines and wells under certain conditions of near freezing temperatures and high pressures. Their formation is averted by ensuring that water vapour levels in the gas are kept below specified levels. See also Treatment . Dew Point . Hydrates are found naturally beneath the ocean at depths greater than 300m in many areas, where they are estimated to have locked up many trillions of cubic metres of methane. There is speculation that these hydrates may provide a commercial resource in the future. Hydrates have also been proposed as a means of transporting natural gas by sea, possibly competing with LNG. Hydrocarbon An organic compound containing only the elements hydrogen and carbon. Hydrocarbons exist as solids, liquids and gases. Impurities At the wellhead, natural gas will probably contain methane and various heavier fractions. It may also contain a number of non-hydrocarbons, some or all of which will need to be removed. There may also be substances introduced into the well as a result of drilling operations, such as inhibitors, mud etc. The principal harmful impurities in the gas itself are likely to be carbon dioxide and sulphur compounds, notably hydrogen sulphide, which can create corrosion in the pipelines in the presence of water and can seriously damage chemical plant units built of aluminium. Hydrogen Sulphide is also extremely toxic. Excessive water vapour can lead to the formation of acids and Hydrates . Some impurities, such as sulphur or helium, can be recovered economically as by-products if in sufficient concentration in the gas. Other impurities, such as inert gases and nitrogen cause no directly harmful effects but dilute the Calorific Value of the gas and mean that pipeline capacity is being wasted. Whether or not they should be removed is simply a question of economics. See also Treatment . Natural Gas Liquids . Condensates. Independent Power Plant (IPP) An IPP is an electric power generation plant owned and operated independently of the major national or regional entity, producing electricity for an industrial complex andor for sale to the electricity grid. Inert Gas: A chemically inert gas, resistant to chemical reactions with other substances. Integrated Gasification Combined Cycle (IGCC) A means of generating electricity from coal and other low grade hydrocarbons by gasifying them at the electricity generation site thereby gaining some of the efficiency of Combined Cycle Gas Turbine generation. While the chemical amp engineering principles are well understood it has yet to be demonstrated as a commercial proposition. International Energy Agency A Paris-based organisation which co-ordinates the energy policies of its member countries. The IEA also compiles detailed energy statistics and country reports, including countries outside the organisation itself. An autonomous wing of the Organisation for Economic Co-operation and Development (OECD). International Gas Union The International Gas Union (IGU) was founded in 1931. A worldwide non-profit organisation of national gas industry associations whose objective is to promote the technical and economic progress of the gas industry. Organises the triennial World Gas Conference. International Petroleum Exchange The IPEis an energy futures and options exchange based in London. Gasoil futures have been traded since 1981, Brent crude futures from 1988, and natural gas futures since 1997. Absorbed into ICE, the InterContinental Exchange in 2005. See also New York Mercantile Exchange. Interruptible Gas Gas made available under agreements permitting the supplier to terminate, or interrupt deliveries, usually for a limited number of days in a specific period. Usually sold at a reduced price and used to boost salestransportation in slack seasons (normally the summer). Important in load balancing because (by reducing gas demand) it is an alternative to using stored gas. The converse of Interruptible Gas is Firm Gas. Into Plant Price (IPP) The price charged for gas at its entry to the plant. Joint And Several A contract term relating to responsibilities under a contract, usually for payment, often misunderstood. Where, for example, there are several buyers in one contract, a joint responsibility does not mean an equal or pro rata responsibility. It means that if one buyer defaults on its liabilities the other buyers will be liable to make good that default. Where responsibilities are several, each party is responsible only for its own default. Kyoto Japanese city which was the location for an international agreement on the need to reduce the level of emissions of greenhouse gases into the Earths atmosphere. Lean Gas Lean gas is gas high in methane content (typically 95 or more) and with few higher fractions. Hence of relatively low Calorific Value . Also known as Dry gas. The converse of Rich Gas. Liberalisation A term often confused with Deregulation but often meaning quite the reverse. Liberalisation is the process of freeing a market from what are perceived as undue monopolistic forces, to achieve which a high degree of regulation may be required, at least in early years. Limited Access Limited Access refers to a gas distribution system in which the host pipeline owner moves its own merchant gas under different rules to those applying to outsiders contracting for spare capacity. The system applies to local distribution companies and intrastate pipelines in the US and is analogous to but not identical with Negotiated Access . See also Common Carriage. Limited Liability A provision in very large gas contracts under which limits are set to the amounts payable by a defaulting party in a contract. Line Pack Line pack is a procedure for allowing more gas to enter a pipeline than is being withdrawn, thus increasing the pressure, packing more gas into the system, and effectively creating storage. The packed gas can subsequently be withdrawn when needed. A useful method of meeting short term (hourly or diurnal) peak demand requirements. In some areas, where there is a particularly high peak demand, a series of additional pipeline loops may be laid near the entry to a network to provide additional line pack. Such systems are effectively a modern version of the traditional Gas Holder. Liquid Market A trading market characterised by the ability to buy and sell with relative ease, usually because there are many buyers and sellers. Liquefied Petroleum Gas Liquefied Petroleum Gas (LPG) is Propane . Butane . or propane-butane mixtures which have been liquefied through pressure, mild refrigeration, or a combination of both. Usually a derivative of refinery operations but often stripped out of natural gas streams, if rich enough. Conventionally sold in steel containers as Bottle Gas . Not to be confused with LNG. LNG (Liquefied Natural Gas) LNG is Natural Gas which has been cooled to a temperature, around the boiling point of methane (-162C), at which it liquefies, thus reducing its volume by a factor of around 600. The exact boiling of any gas mixture and the reduction in volume will depend on its composition. The process of Liquefaction is carried out in a liquefaction plant. Mostly these are very large scale plants built for projects transporting gas by sea, but in many countries small LNG plants have been built to liquefy gas during the seasons of low demand to provide Peak Shaving when required. LNG Plants consist of one or more LNG Trains, each of which is an independent gas liquefaction unit. It is more cost effective to add a train to an existing LNG plant, than to build a new LNG plant, because infrastructure built for early trains, such as ship terminals and other utilities, may be capable of being used or expanded for new LNG trains. The term Train is sometimes extended loosely to embrace the relevant shipping, storage and other facilities required to bring the resultant LNG to market. Liquefied gas is transported and stored as a boiling liquid under slight positive pressure until required for use, when it is warmed and allowed to re-gasify. In the case of Peak Shaving, the gas will normally be regasified at the plant itself or possibly transported for short distances by road, but large scale transportation is by sea, in specially designed insulated LNG vessels and delivered to LNG terminals, which have the requisite facilities for storage and regasification - the process by which LNG is warmed, usually through a heat exchanger, in order to become once more gaseous before emission into the Gas Grid. Load Duration Curve A visual and statistical expression of a number of (daily) demands over a long period, most often a year. Demands are normally ordered with the highest to the left and the lowest to the right, so that the horizontal scale bears no relation to calendar timing. Can be used, among other things, to measure volumes of demand (or supply) above a given threshold. The area beneath the curve and between horizontal thresholds represents the volume required to supply a particular market segment. The approach is used in both electricity and gas industries. Load Factor A measure of utilization for plant, or of the relationship between average and peak demand or supply, as determined by the formula: Average x 100 Peak. For supply and demand calculations average and peak most often refer to daily demand within a year, but any other periods are possible. The resulting figure is usually expressed as a percentage but, where the period covered is a year, the percentage is sometimes multiplied by 8760, so that the load factor is expressed as a number of hours. Thus a 50 Load Factor can also be expressed as 4380 hours. See also Swing. Local Distribution Company (LDC) A company that distributes natural gas primarily to small, residential and industrial end-users. Looping Increasing the capacity of a pipeline system, by adding parallel piping along part or whole of the route. Does not apply to the addition of compression facilities. Low Sulphur Fuel Oil (LSFO) Fuel oil with a low sulphur content. Usually less dense than High Sulphur Fuel Oil . In new markets with gas-to-oil competition this often represents the marker fuel for large segments of the industrial market. Madrid Forum The Madrid Fotum, otherwise known as the European Gas Regulatory Forum, set up to discuss issues regarding the creation of a true internal European gas market. The participants include national regulatory authorities, Member State governments, the European Commission, transmission system operators, gas suppliers and traders, consumers, network users, and gas exchanges. Make Good Make Good Gas is gas which a buyer must take in a later year because it has failed to take its full Annual Contract Quantity obligation in an earlier year, but has not used its full Downward Quantity Tolerance . It must nevertheless take excess gas in subsequent years to make good its deficiency, before it is entitled to claim any Make Up Gas to which it is entitled through shortfalls greater than the Downward Quantity Tolerance. Make Up Make Up Gas is gas for which a buyer has paid under Take or Pay obligations but not taken, and may have rights to receive in subsequent years for no further charge or at reduced prices after it has taken gas in excess of an agreed threshold volume. This is commonly the Annual Contract Quantity but may, for example, be ACQ minus Downward Quantity Tolerance . Make up gas should not be confused with Make Good Gas. Memorandum of Intent (MOI) Also known as Confirmation of Intent and Letter of Intent. A half way house to the signing of a full contract. Its legal status is rather unclear and its value lies largely in how it is viewed by the parties concerned. It will normally be a fairly brief document setting out the principal framework of the contract and specifying a date by which it is expected that a full contract will be completed. An MOI will often have a relatively brief validity, but in some cases they have served to govern active operations over a period of years. Also known as a Memorandum of Understanding (MoU) and Heads of Agreement (HoA). Merchant Pipeline A pipeline system which itself buys and sells part or all of the gas it transports, in contrast to a pipeline which simply carries gas on behalf of others. See also Open Access . Negotiated Access . Common Carriage. Meter Measuring devise, usually located at a point where ownership is transferred, for example at the entry to a customers premises, city gate, national border or gas processing plant. Note that to determine the energy content of the gas it will be necessary to monitor the composition amp hence calorific value of the gas. This is done at high pressure meter stations but not normally downstream of a city gate. Depending on the size of flow, meters may be: Flow meters, measuring gas throughput using a rotor which is made to revolve by the gas flowing through them Ultrasound meters, more sophisticated, based on the principle that sound waves travel faster with than against the flow. By measuring the difference in travelling time between the two sets of measurements the gas flow rate can be measured to an accuracy of more than 0.5 Orifice plate meters, older, and less accurate than other meters. Calculate flow rates by measuring the drop in pressure over a pierced obstructing plate placed in the pipeline. See also Telemetry. Methane A colourless, odourless flammable gas, lighter than air under normal conditions (CH4, often abbreviated to C1 in non technical usage). Methane is the first member in the alkane (paraffin) series and is the chief constituent of Natural Gas . At atmospheric pressure, it liquefies at -162C. Methanol Methyl alcohol, produced from natural gas via Synthesis Gas . Used as a chemical in the resin and paint industry and in the manufacture of Methyl Tertiary Butyl Ether, (MTBE) and acetic acid, but also of interest as a possible total or partial substitute for motor gasoline in cars. Very toxic. Middle Distillate Synthesis (MDS) A chemical process using the Fischer-Tropsch synthesis method for making synthetic middle distillates (principally naphtha, kerosene and gas oil) from natural gas. Midstream Those activities in the gas chain concerned with moving gas between the source and local distribution. See Upstream. National Balancing Point (NBP) The NBP is an imaginary (notional, or virtual) point at which all gas that has paid the entry charge to enter the UK National Transmission System is deemed to be located. The point at which most UK gas trading takes place, and the largest gas hub in Europe. See Entry Exit. Natural Gas Natural gas (NG) is a mixture of generally gaseous hydrocarbons occurring naturally in underground structures. Natural gas consists mainly of Methane and variable proportions of Ethane . Propane and Butane . There will usually be some condensate andor oil associated with the gas. More specifically, the term is also used to mean treated natural gas which is supplied to industrial, commercial and domestic users and meeting a specified quality. Natural Gas Act (NGA) Seminal example of deregulation liberalisation in the USA. Natural Gas Liquids (NGLs) Heavier hydrocarbons found in natural gas production streams and extracted for disposal separately. Within defined limits ethane, propane and butane may be left in the gas to enrich the Calorific Value . Whether to extract them or not is largely a commercial decision. Heavier fractions which are liquids at normal temperatures and pressures will be removed. The terms Natural Gas Liquids and Condensates are in practice used virtually interchangeably. Rather confusingly, there is no agreement on whether the term NGLs includes or excludes LPGs and both usages are current. Natural Gasoline Butanes and heavier fractions extracted from rich natural gas which, after stabilisation (removal of the lighter fractions) may be blended into motor gasoline. Negotiated Access Negotiated Access is a restricted form of Third Party Access, which excludes the requirement for the access terms to be transparent or applied equally to all applicants. It has been proposed in the European Union as a compromise by opponents of Open Access. Sometimes abbreviated to nTPA. Broadly defines access by one party to another partys facilities through negotiation, the result of which is, by implication, confidential, and not necessarily consistent with negotiations between the facility owner and other parties. See also Access . and Limited Access. Net Calorific Value, (NCV) The heat generated by the complete combustion of a unit volume of gas in oxygen, excluding the heat which would be recovered by condensing the water vapour formed. Net Calorific Value is usually seen as a measure of the effective heat produced rather than the total heat in the gas. Also known as Lower Calorific Value or Lower Heating Value. For natural gas, typically 10 lower than the GHV or HHV. See also Gross Calorific Value. Netback The price or value of a gas, at e. g. the border or the wellhead, calculated by deducting the costs associated with getting it from that point to the eventual point of sale from its competitive value at that point of sale. Used to estimate the comparative value of selling gas to various markets, and the worth of producing gas at all. Network Code A detailed contractual regime governing access to a gas grid. Network Codes exist or are being developed in several countries, especially in Europe. In North America the rules of the system are referred to as The Tariff. In particular, the contractual regime for the gas grid in Great Britain operated by National Grid. It is continually amended through rules approved by the GB energy regulator, ( Ofgem ). See also Tariff and Rates. New York Mercantile Exchange (Nymex) The worlds largest physical commodity futures exchange. Has existed for 130 years and pioneered the development of energy futures and options contracts in the 1970s. Nitrogen Oxides Oxides of Nitrogen (NOx) resulting from the combustion of fuels, causing atmospheric pollution in the form of smog. Non Associated Gas Non-Associated is gas found in a reservoir which contains no crude oil, and can therefore be produced in patterns best suited to its own operational and market requirements. See also Associated Gas. Odorants Strong smelling chemicals injected into natural gas, which otherwise is odourless, in order to make its presence more easily detectable. See Mercaptans. Odorisation The process of giving odourless natural gas a smell for safety reasons by injecting small quantities of organic sulphur compounds, such as Mercaptans . typically at the rate of 30 ppm. Usually carried out at the city gate or at the exit from the high pressure transmission system. OFGEM Office of Gas and Electricity Markets, (OFGEM) The regulator for the gas and electricity industries in Great Britain. Governed by the Gas and Electricity Markets Authority . Its powers are provided by the Gas Act 1986, the Electricity Act 1989 and the Utilities Act 2000. Successor organisation to OFGAS and OFFER, the former separate Gas and Electricity Regulators. Offtake Point The point in a gas system where gas is taken by supply pipe to a consumer. Oil Gasification The conversion of oil or naphtha into gas to be used as a fuel. See also Manufactured Gas. On the day Commodity Market (OCM) System of within-day gas trading introduced into Great Britain in 1999. A screen-based system designed to allow shippers, traders and the system operator (then Transco, now National Grid) to resolve within-day demand and supply imbalances in an orderly fashion. Open Access A system offering all applicants access to specified infrastructure. See Common Carriage. Open Cycle Gas Turbine (OCGT) A gas turbine, often derived from aero-engines, used for peak generation of electricity. Also used in conjunction with a steam turbine in a combined cycle power plant. When only the gas turbine is used it may be termed single cycle. Open Season A procedure for demonstrating to a regulator that capacity is offered on a transparent basis. It is used principally where pipelines are required by regulation to offer only transportation services, for example in North America and the Southern Cone of South America. It is also being used elsewhere as a means of gathering information about potential interest in a pipeline. LNG, storage etc project to help the sponsors decide how and when to size the project. Off-Peak The period during a day, week, month or year when the load being delivered by a gas system is not at its maximum volume. Over the Counter Trading (OTC) Trading that takes place outside a formal Exchange. Peak Day The day in the year on which the demand for gas is highest. In temperate areas this is normally a cold day in mid winter. In warmer areas it may occur midsummer, when there is a high air conditioning load met either directly by gas or by gas-fired power. A crucial indicator in planning and sizing gas infrastructure. Peak Hour The hour in the day in which demand for gas is highest. Chiefly relevant to distribution systems. Is normally around the midday or evening meal time Peak Load The maximum load produced or consumed by a unit in a stated period of time. In some tariff systems it is an important component of the tariff design, since it defines the capacity that is booked in the gas delivery system and must be paid whether or not used. Peak Shaving Peak shaving is a means of reducing the Peak Load on the gas transportation and supply system by supplying some gas from sources at or close to the point of ultimate consumption, thus improving the average Load Factor . Peak shaving may be daily or seasonal and will be handled in a variety of ways: - Underground storage . peak shaving LNG plants, Line Pack . Gas Holders . propane-air plant and, occasionally, special peak shaving supply contracts. A non-storage alternative to peak shaving is to interrupt I nterruptible Gas supplies. Permeability A measure of the ease with which liquids or gas flow through a reservoir rock. Compare this with Porosity . Gas will flow more easily than oil, and so can be recovered from rocks with lower permeability. Permeability is measured in Darcies. Gas reservoirs may have permeabilities of only a few millidarcies. Petrochemical An intermediate chemical derived from petroleum, hydrocarbon liquids, or natural gas, such as ethylene, propylene, benzene, toluene, and xylene. Pig Equipment used to clean or flush out liquids and other accumulated and unwanted items from the inside of an oil or gas pipeline. It is inserted into the pipeline and carried along by the flow of oil or gas. An intelligent pig includes measuring and sensing equipment which can be used to inspect a pipeline internally, which is useful after it has been buried underground Pipeline A tube for the transportation of crude oil or natural gas between two points, either offshore or onshore. Pipeline Capacity The amount of oil or gas that can be passed through a pipeline over a given period of time. Plateau In long term gas contracts the period of years for which the Annual Contract Quantity remains flat. The Plateau will normally be preceded by a build up period, during which the volumes increase and, in the case of a Depletion Contract will be followed by a period of decline until further production is no longer economic. Porosity The proportion of a rock volume (expressed as a percentage) that is occupied by the voids between mineral grains. Used to help estimate the volume of hydrocarbons in a field. Compare this with P ermeability . Power Purchase Agreement (PPA) A contract between a power station and the electricity purchasing organisation for the sale of electricity. Primary Energy The gross amount of energy used, measured in the quantities of the original fuel produced (e. g. crude oil) before conversion to other forms (e. g. refined petroleum products or electricity). Thus hydroelectric power and nuclear power are Primary, but power from generating stations consuming fossil fuels is not. Production Sharing Agreement (PSA) An agreement between an international producing company and a host government or state oil company under which the international company acts as risk-taking contractor investing in exploration andor production facilities in return for the right to export or sell a quantity of gas or oil that may be produced from the Concession or Block . Sometimes known as a Production Sharing Contract. The terms are interchangeable and the use of one or the other depends on the country. Profit Gas Frequently used to signify the gas received by a Contractor in a Production Sharing Agreement to provide the profit in the operation. Normally the Contractor will receive Cost Gas to cover its costs and, after other minor provisions, the remaining gas will be split with the host government in agreed proportions. In some countries profit gas is also subject to income tax, in other jurisdictions the State Oil Company is assumed to pay the income tax liability of the contractor. The proportion of profit gas is adjusted depending on local practice. May be used to signify the totality of gas remaining after Cost Gas, Royalty and similar items, including therefore both the Governments and the Contractors shares. Project Financing A method of financing in which the lender makes loans directly to a project and may claim repayment only out of that project. In theory, the lender has no recourse to the project sponsors other assets (non-recourse financing) but in practice this is rare. More commonly the extent of the sponsors liability is strictly defined (limited recourse financing). Propane A member of the alkane (paraffin) group of hydrocarbons with three carbon atoms in its molecule ( C3H8, often abbreviated to C3 in non technical usage). A frequent component of natural gas, also sold as a form of Bottled Gas . Liquefies at -42C. Proven Reserves Those quantities of petroleum which, by analysis of geological and engineering data, can be estimated with reasonable certainty to be commercially recoverable, from a given date forward, from known reservoirs and under current economic conditions, operating methods, and government regulations. Proven (proved) reserves can be categorised as developed or undeveloped. Where probabilistic methods have been used to estimate reserves, proven reserves are those with a better than 90 chance of being economically recoverable. Sometimes abbreviated as P90. Reserves with a greater than 50 chance but less than 90 chance are defined as Probable, or P50. Reserves with a greater than 10 chance but less than 50 chance are Possible or P10. Reserves may be classified as proved, if facilities to process and transport them to market are operational at the time of the estimate or there is a reasonable expectation that such facilities will be installed. Reasonable expectation is usually taken to mean that a developer has taken the decision to build the necessary facilities and the development plan has been approved by the relevant authorities. Thus large resources, such as those known to exist in North Alaska, are not classified as proven because there is no route to market. Different countries have adopted many different definitions of reserves, but gas contracts often refer to the Society of Petroleum Engineers (SPE) definitions. These and similar definitions from the World Petroleum Council were harmonised in 1997. Public Service Obligation A Public Service Obligation (PSO) is a requirement imposed by government on a company or companies to provide services which might not otherwise be profitable but are judged to be in the public interest. These could, for instance, include supplying gas to small or poor consumers, ensuring that appliances and other infrastructure is operating efficiently and safely, and ensuring that there are sufficient back-up gas supplies to cover emergency interruptions in supply. Public Utility Commission (PUC) State commissions in the USA responsible for regulating gas, and other utilities that operate within the boundaries of the state. See Regulation. Ramping Rate The rate at which the level of production can be increased after a partial or complete interruption. Rates North American term for the charges for the use of pipeline and storage capacity, referred to in other parts of the English-speaking world as Tariff. The North American definition of Tariff is more nearly equivalent to Network Code. Raw Natural Gas Natural gas still containing impurities and unwanted substances, such as water, nitrogen, carbon dioxide, hydrogen sulphide gas and helium. See also Impurities . Treatment. Recovery Factor The percentage of gas or oil in place in the reservoir which can be economically recovered. Gas Recovery factors may be around 60-70 in reservoirs with water drive from an Aquifer and up to 90 in Depletion Drive Reservoirs. Regasification The reconversion of LNG into gas suitable for pipeline transportation. See LNG. Regulated Access Access to infrastructure under terms and conditions set by or agreed with a Regulator . Such access will usually be open to all qualifying customers. See Common Carriage. Regulator (1) A mechanical device for controlling the pressure of gas within acceptable limits. Typically installed when has enters a low pressure distribution system for final use by small customers. (2) The person or body appointed to oversee the operation of the regulated parts of a gas industry. See Regulation. Regulation Regulation is a substitute for free market operation typically, in the gas industry, where all or part of the operations are carried out by institutional or natural monopolies. Provides a temporary or permanent counterweight to the economic power of the monopoly. Often exercised politically by government departments, but in many countries independent regulation is thought preferable. In any case the rules governing regulation will normally have been laid down explicitly by government legislation. Regulation can be economic restricting the revenue and profits of operators - or legal policing legislation. Regulators are normally closely involved in the setting up of liberalised market systems, when they may use their central position to interpret and rule on the applicability of legislation either ex-ante or ex-post. See Common Carriage. Renewable Energy An energy form, the supply of which is partly or wholly regenerated in the course of the annual solar cycle. Thus solar and wind energy, hydropower and fuels of vegetable origin are regarded as renewable mineral fuels and nuclear power are not. Reservoir A reservoir is an accumulation of oil andor gas in a permeable and porous rock such as sandstone. A petroleum reservoir normally contains three fluids (oil, gas and water), which separate into distinct sections, owing to their varying specific gravities. Gas occupies the upper part of the reservoir as it is the lightest, oil the middle section, while water occupies the lower section. See also Permeability . Porosity . Gas Cap . Aquifer . Solution Gas . Proven Reserves. Reticulation A reticulation network is a small diameter, low pressure gas system serving residential and commercial customers. (From the Latin word reta, meaning net). See also Distribution. Retrograde Condensate A gas condensate which, in the reservoir, is close to the Dew Point of the fluid. A small reduction in pressure, by production of the field, leads to the condensation of higher hydrocarbons in the reservoir, causing a lower Recovery Factor . Royalty A tax on production volumes, often paid in kind, which is levied as a percentage of production. It is therefore not related to the profitability of the production project, merely to the volume of gas (or oil) produced. R:P Ratio The Reserves: Production Ratio is the number of years that current reserves would last at current production levels. Thus reserves of 100 divided by consumption of 20year gives an R:P ratio of 5, and implies a life of 5 years for the reserve. RPI-X A regulatory formula by which a regulated monopoly is allowed to increase its prices each year by the retail price index (RPI) minus a defined amount or percentage x (x is a variable). Gives consumers falling real prices and forces the utility to reduce costs if it is to maintain its level of profitability. Sales Gas Raw gas, after processing to remove LPG, condensate and carbon dioxide. Sales gas usually consists mainly of methane and ethane and is odorised. See Odorisation. Salt Cavity Storage The storage of gas in caverns leached out in gas-tight salt strata. Such caverns may be generated during the recovery of salt for commercial purposes, or may be purpose-built for gas storage. Scrubbing The process of purifying a gas or liquid by washing it with suitable chemicals in a contact vessel. Seal The layer of rock overlying a gas field which prevents the gas escaping from the reservoir. It is therefore of low Permeability . Salt and fine clays can provide good seal. Seasonal Normal The average (or normal) result for the time of year. Thus Seasonal Normal Temperature (SNT) is the average temperature on a calendar day, where the average has been measured over a suitably long period. Likewise Seasonal Normal Demand, Seasonal Normal Weather. SNT is an important factor in developing forecasts of gas usage. See Weather Correction. Seasonal storage Storage designed to be filled at times of low (season) demand and emptied at times of high demand, over months rather than days. Security of Supply Security of supply is a term with several meanings including: the provision of adequate infrastructure to cope with annual and peak demand the provision of sufficient gas to meet annual and peak demand ensuring that a country or area does not rely exclusively on one, or very few sources of supply. Seismic Survey A technique for establishing the presence of underground geological strata using sound waves. There are two main techniques - reflection or refraction. In the oil and gas industry by far the most common is reflection. In a reflection survey sound waves are sent into the ground and the echoes from boundaries between rock with different properties of density and sound velocity are recorded. The sound waves recorded at the surface can then be used to create maps of the rock layers in the subsurface to reduce the risk of drilling dry holes. A reflection seismic survey may be either 2D, in which the reflections are recorded along a line or 3D, in which the lines are very closely spaced to deliver a three dimensional view of the subsurface. A refraction seismic survey is a different technology in which the sound waves are refracted along rock boundaries rather than reflected from them. Send-Out The quantity of gas delivered by a plant or system during a specified period of time. Shipper A party negotiating for the transport of gas on its own behalf or as an agent for another. In liberalised markets shippers may not be allowed to operate transportation systems. Slug Catcher Plant installed in a gas pipeline system or gas processing plant to catch slugs of liquid. Usually this takes the form of a long section of pipe, inside which the pressure is allowed to drop by a controlled amount. See also Pig. Solution Gas Solution Gas, unlike Cap Gas is Associated Gas dissolved in oil. Produced inevitably with the oil and separated from it at the well-head. Solution Gas production is thus a function of oil production and of the GasOil Ratio . which changes over the life of the field. It is therefore an unreliable gas supply and difficult to market, unless the buyer or seller have large alternative sources. Has in the past largely been flared or vented but this is becoming less acceptable, largely for environmental reasons, although is still not uncommon in remoter areas. Separation is often carried out in two or three stages to maintain the gas pressure for pipelining as far as possible. Gas from the final stage separator is at low pressure and is normally used in the field or on the platform during production. The gas may be re-injected into the reservoir if it will not break through into the oil wells. Sour Gas Gas containing a high level of Carbon Dioxide or Hydrogen Sulphide, which are corrosive in the presence of water. They may therefore require drying or removal to preserve the pipeline. The converse of Sweet Gas. Spark Spread The spark spread represents the difference between the cost of fuel and the price of electric power produced. A positive spread indicates that the price of the power is higher than that of the fuel, and the spread is profitable. The spread can be calculated for any input fuel, such as natural gas, coal, or heating oil. Specification The technical description of the allowable limits of the chemical composition of gas which may be admitted into a pipeline or process. Specific Gravity The ratio of the density of gas to that of air, or the ratio of the density of a liquid to that of water, in both cases at the same temperature and pressure. Spot Trading A loose term covering the buying and selling of gas other than under a long term contract. Generally in trading parlance spot delivery means immediate delivery. Standing Charge Tariff term for a fixed charge, typically per quarter or per year, irrespective of the amount of gas actually taken. Synonymous with Connection Charge but to be distinguished from Demand Charge. Storage For natural gas storage facilities fall into several categories. Seasonal storage comprises depleted gas fields Aquifers S alt Cavity Storage mined caverns and disused mines. Peak storage includes Gas Holders . Line Pack . lengths of pipeline buried specifically for storage use, and LNG storage used either for base-load or peak-shaving duties, depending on the market. Increasingly used in liberalised markets to enable gas to be trade at any time of the year for reasons not related to peak demand. See also Peak Shaving . Straddle Plant A gas processing plant that straddles a gas transportation pipeline to remove NGLs from the gas stream. Because it is often more economic to transport Rich Gas a straddle plant is required to process the plant to final sales specification. The alternative location of a gas processing plant is close to the producing field. NGLs are then transported as liquids away from the field area either by separate pipeline or other means. Supply Contract A contract under which the seller undertakes to supply gas in guaranteed volumes over a fixed period of time. A Supply Contract is therefore in sharp contrast to a Depletion Contract as the seller assumes the volume risks. Whilst certain fields may be envisaged in the contract, the seller will normally have the right to substitute other suitable gas if necessary. Swaps (1) Arrangements under which gas destined for a market is delivered elsewhere, and substitute gas is supplied to the final market. For instance, Nigerian LNG contracted to Italy is delivered to France, and other gas contracted to France is delivered to Italy. (2) In trading, the exchange of a fixed price for a floating price for a future delivery. Sweet Gas Gas containing little or no Carbon Dioxide or Hydrogen Sulphide. Converse of Sour Gas. Swing The inverse of Load Factor . defined as: Peak volume transported (sold) Average volume transported (sold) Expressed as a percentage. Thus a load factor of 60 is a swing of 167. Often used to describe the flexibility of supplies over a year. Synthesis Gas Also known as Syngas, Synthesis Gas is a mixture of carbon monoxide and hydrogen produced from methane or other hydrocarbons and steam and used to produce various chemicals, notably methanol. It is also the basis for the Fischer Tropsch process. See also: Middle Distillate Synthesis. Synthetic Gasoline Motor gasoline produced from coal (by the Fischer Tropsch process) or from natural gas (by the Fischer Tropsch process or via methanol). See also Middle Distillate Synthesis. Take or Pay Take or Pay (TOP) is a common provision in gas contracts under which, if the Buyers annual purchased volume is less than the Annual Contract Quantity minus any shortfall in the Sellers deliveries, minus any Downward Quantity Tolerance . the Buyer pays for such a shortfall as if the gas had been received. The Buyer may have the right in subsequent years to take the gas paid for but not received, either free or for an amount to reflect changes in indexed prices. See also Make Up Gas. Tariff A schedule of rates or charges offered by a common carrier or utility. Tariffs are commonly available for all parts of the gas industry where third party access is enforced or offered, for example for gas transmission in pipelines, for the use of gas stores, for gas sales to residential customers. Telemetry A technique used in the gas industry for recording information at a distance from the Meter or other recording device, typically by radio transmission of the data. Temperature Demand Analysis The statistical analysis of the causal relationships between weather (and other) factors and the demand for gas. An essential prelude to forecasting demand. See Seasonal Normal and Weather Correction. Temperature Correction The process of adjusting actual gas usage to what it would have been at Seasonal Normal Temperatures, to allow comparisons to be made between results for different time periods, typically years. See weather correction. Title Transfer Title transfer is the transfer of which ownership of gas from the seller to the buyer. Typically this may occur somewhere between the well head and entry into the transmission system, at national border crossings, at the City Gate etc. In the world of traded gas, possible points of transfer become more numerous. A special case is the transfer of LNG at some specified point on the high seas. See Delivered. Trading Volume The number of contracts that change hands during a specified period of time. See also Churning. Transit The transportation of gas through a country or gas system en route to the final customer. For example, Russian gas may transit through Ukraine en route to customers in western Europe. Transmission The transportation of large quantities of gas at high pressures, often through national or regional transmission systems. The gas is then transferred into local distribution systems for supply to customers at lower pressures. Transmission Company The company responsible for operating a transportation system. In liberalised markets there is increasing pressure for such companies to be restricted to offering capacity in pipelines for sale, and to be barred from selling gas itself. The companies are also commonly known as Transmission System Operators (TSOs) a title which reinforces their restricted role. See Unbundling. Transmission Pipeline A network of pipelines moving natural gas from a gas processing plant via compressor stations, to storage centres or distribution points. Transparency A general term meaning open publication of information. In the gas industry it is generally used in relation to costs, prices and capacity, where information has traditionally been considered commercially confidential. Costs and prices generally reflect a number of elements, such as production, transportation, storage, service. Transparency generally involves separating out or U nbundling these elements, usually as a result of regulatory requirements. A further step towards transparency involves the publication of the methodology used to calculate the different elements of costs and prices. Transporter A gas pipeline company transporting gas belonging to other companies. Also the operator of LNG vessels. See Transmission Company. Trap A configuration of reservoir and seal rocks that can confine gas (or oil) which are lighter than water normally contained in the reservoir rock. Structural traps are formed by a closed structure of R eservoir rock overlain by a sealing formation (the Seal ). May also be formed by stratigraphic changes within a reservoir rock in which case it is known as a stratigraphic trap. Treatment Any gas purification process, but most generally applied to the treatment of gas immediately after production, to bring it to acceptable standard for the market in question andor to extract valuable components for separate sale. This may involve the removal of LPGs and will certainly involve stripping out Condensates . Carbon Dioxide and Hydrogen Sulphide and other sulphur compounds (see also Acid Gas ) mercury and excessive water which may be in the raw gas. Other impurities are occasionally encountered. Whether other inert gases such as nitrogen, helium etc are extracted will be a matter for economic evaluation. UKCS United Kingdom Continental Shelf. Unbundling Unbundling is a term with several meanings for the gas industry but more accurately, and originally, it was used to denote the separation of different services and the charges associated with them. Originally used in the US in restructuring the telephone industry. it was adopted in the gas industry to denote the separation of gas sales from transportation and storage services. This is still the most usual meaning of the term, particularly in North America, where large customers are now free to purchase gas and services separately. However the European Commission uses the term Unbundling to mean the financial disaggregation of different functions within integrated companies, such as transmission and marketing. Where companies perform multiple functions, the Commission has sought to require separate accounting for the functions. Its aim is therefore much more related towards Transparency and eliminating the potential for anti-competitive cross subsidisation activities. Underground Storage The storage of gas, for strategic or peak shaving reasons, in underground reservoirs. Depleted gas fields are often suitable. Other possibilities include depleted oil fields, Aquifers and Salt Cavity Storage . In the context of LNG, underground storage refers to normal LNG storage tanks which are, however, buried to provide greater safety in the event of leakages. Unitisation Agreement When a gas field extends over two or more production licences or leases with different ownership, most countries require that the field owners unitise their holdings i. e. decide how the reserves and production of the total field will be shared between the licensees, thus enabling the efficient depletion of the reserves. The Unitisation Agreement normally provides for the appointment of a field operator, a method of determining the reserves underlying each licence or lease and the frequency of reserve re-determination. Upstream Upstream, Midstream and Downstream are imprecisely defined terms used to separate activities along the gas and oil chain into homogenous groups. Upstream typically refers to exploration, development amp production of oil amp gas. Sometimes also defined to embrace Midstream, which typically covers transmission (as opposed to distribution) LNG shipping etc. Downstream typically refers to activities associated with delivery to final consumers, such as distribution systems and connections to customer premises. Water Drive In a porous rock, as gas is withdrawn from the reservoir, water expands into the region formerly occupied by the gas as pressure is released. This often has the result of trapping volumes of gas so that they cannot be produced, thus reducing the recovery of gas. Not a problem with a D epletion Drive Reservoir . See Aquifer. Water Gauge A measure often used to express the pressure of gas in distribution systems, using water instead of mercury. The gauge records how far up a gradated tube gas will lift a column of water. Distribution systems normally operate at about 300mm (12 inches) water gauge (i. e. 300mm above atmospheric pressure). For comparison, atmospheric pressure is a little above 10 metres of water. Wayleave The strip of land around a gas pipeline or other utility to which the utility has legal right of access for building and maintenance. Weather correction A procedure for estimating what customer demand would have been in S easonal Normal weather conditions. Thus in a cold year seasonal normal demand will be lower than actual demand and vice versa. Well A hole drilled into the ground, mostly by rotary rigs, in which a drill bit, which actually cuts the rock, is turned on the end of a drill string, made up of lengths of hollow steel pipe which are added to the string as the bit drills deeper into the ground. Wells have various descriptions depending on the stage of the production process at which they are drilled. Exploration wells are drilled to discover if gas (or oil) can be found Evaluation or appraisal wells are drilled to obtain more information about a previous discovery Development wells are drilled to produce gas from a field which is being developed, and are called Producing wells when the field enters commercial production. Wheeling Physically redirecting gas from one pipeline system to another at a Hub as opposed to changing the title by swap arrangements. Wobbe Index Occasionally referred to as the Wobbe number. A measure of the rate at which gas will deliver heat on combustion and hence of the compatibility of a gas with gas burning equipment. Working Gas In a gas store, the total volume of gas present less C ushion Gas . In other words the gas available for normal working. Hence working gas capacity - the total capacity of a storage facility minus cushion gas. GLOSSARY OF UNITS Absolute Pressure The sum of Atmospheric Pressure and Gauge Pressure i. e. pressure by reference to a vacuum Atmosphere: A measure of pressure, now largely superseded by the Bar to which it is nearly identical. Originally equal to 760 mmHg it has now been redefined as 101,325 pascals and consequently 1 atmosphere 1.01325 bars. Atmospheric Pressure The pressure of the weight of air and water vapour on the surface of the earth. Bar The most used unit for expressing gas pressure. It is equal to 100,000 pascals (Nm2), which is the official SI unit. 1 Bar is approximately atmospheric pressure. bbl A US barrel, 1 barrel 0.159 cubic metres 42 U. S. gallons (approx35 imperial gallons). The abbreviation is also sometimes written as B or b. bblday Barrels per day. Usually used to quantify a refiners output capacity or an oilfields rate of flow. Bcm Billion cubic metres (i. e milliard or 109 cubic metres). Billion In the US 109. Although elsewhere billion often signifies 1012, the Natural Gas industry has generally adopted the US usag e. Boe Barrels of oil equivalent - a frequently used number to quantify general energy requirements for practical purposes. One boe is usually taken as representing 5.8 MMBtu gross. British thermal unit A unit of heat still widely used in the gas industry, notably in North America and in LNG. Originally defined as the amount of heat required to raise the temperature of one lb of water from 60 to 61 Fahrenheit, it is now defined in relationship to a fixed number of Joules (1055.056 to three decimal points). The most common multiple is one million Btu, normally abbreviated to MMBtu and U. S. dollarsMMBtu is perhaps the most frequently used unit for comparing gas prices on a common basis. See also Therm. Cal Calorie. Formerly the SI unit of energy, now no longer part of the system but still extensively used in Europe. The calorie was nominally the amount of heat required to raise 1 gram of water by 1C at 1 standard atmosphere and starting from 14.5C, but is now defined arbitrarily as: 4.1868 J. The most common multiple used is the Megacalorie (Mcal). Cf Cubic feet. Measure of gas volume, referring to the amount of gas needed to fill a volume of one cubic foot at 14.73 pounds per square inch absolute pressure and 600F. cm Cubic metres. Note however that cm is also the official abbreviation for centimetre. Deca Therm Also deka therm. A term sometimes used in the U. S. in lieu of one million Btu. Gauge Pressure The amount of pressure shown by a gauge, i. e. the amount by which the pressure exceeds atmospheric pressure. See also Absolute Pressure. GJ GigaJoule. One GigaJoule is approximately equal to 9.478 MMBtu. One million Btu equals 1.055 GJ. GWh GigaWatts per hour. J Joule - The unit of energy in the SI system and the unit approved by the International Gas Union for the expression of heat in the gas industry. Its definition is one Newton metre. In practice the industry has been reluctant to embrace the Joule for commercial purposes and it is only current in Australia and New Zealand. For practical purposes the multiples most in use are the MegaJoule (MJ) and the GigaJoule (GJ), although Petajoule ( PJ ) is also seen. For quick calculations 1 GigaJoule is very close in value to 1 MMBtu. Kelvin Measurement of temperature equivalent to 1273.16 of the interval between absolute zero and the triple point of water. The official unit of the SI system. The Kelvin is identical to 1 degree Celsius, which is the term most often used in practice, but the scale is different (0C273.16 K). Note incidentally that the Kelvin is itself the unit of measurement and references to 1 degree Kelvin are incorrect. kW KiloWatt One thousand Watts. kWh KiloWatt hour - Together with its multiples, rapidly becoming the most used unit for energy in gas, although its use is not strictly in accordance with the SI system or with IGU preferences. Since 1 Joule 1 Watt per second, the conversion factor 1 kWh 3.6 MJ is exact. Long ton 2240 lb. The most usual form of non-metric ton. Mcf Thousand cubic feet. Mcm Thousand cubic metres. Milliard Synonymous with US billion - 109. MM Widely used in the gas industry to mean a million (106), although this usage is incorrect, according to the SI convention. Similarly M is often used to represent a thousand (103). When the lower case letters m and mm are used, these usually denote a thousand and a million respectively. In everything else M is correctly used to mean Million as in MWh. MMbbl Million barrels. MMcf Million cubic feet. MMcm Million cubic metres. MMscm Million standard cubic metres. Mtoe Million tonnes of oil equivalent. Mtpa Million tonnes per annum, a widely used unit of volume in the LNG industry. MW MegaWatt - one million Watts. ncm Normal Cubic Metre - A cubic metre measured at 0 C and 1013 mbar dry. The most used metric unit for measuring the volume of gas. It differs from the Standard cubic metre ( scm ) in the temperature at which the measurement is made. The Normal cubic metre thus contains about 5 more heat content than the Standard cubic metre. PJ PetaJoule - Standard unit in the Australian gas industry, equivalent to 1 million (106) GJ and therefore roughly equal to 1 million MMBtu . It is therefore close to 1 Bcf or some 30 million cubic metres. ppm Parts per million. Pressure The force exerted by one body on another, measured as force over area e. g. newtons per square metre. Psi Pounds per Square Inch common USEnglish unit of pressure, 14.5psi 1 bar. scf Standard cubic foot - The conditions for measuring the scf are in fact very close to, but not identical with, those for the standard cubic metre ( scm ). Despite its name, there is no single accepted standard for the standard cubic foot but the one most used is 60F and 30 in Hg, dry. scm Standard Cubic Metre - A cubic metre measured at 15C and 1013.25 mbar, dry. The unit of volume recommended by the IGU but not in normal use. See also ncm. Short ton 2000 lb. Used in the US. SI Multiples The SI system uses the following prefixes for multiples of the base units: 103 kilo (k), 106 mega (M), 109 giga (G), 1012 tera (T), 1015 peta (P), 1018exa (E). tce Ton of coal equivalent - Like the barrel of oil equivalent ( boe ) a measure of general energy requirement but now largely supplanted by the boe. Generally taken to have a value of approximately 27 MMBtu. Tcf Trillion (1012) cubic feet. Tcm Trillion (1012) cubic metres. Therm 100,000 British Thermal Units is still occasionally used as a unit for pricing gas, particularly in the UK. Thermie A term virtually identical to 1 Megacalorie but having 15C as its base, used primarily in Spain. toe Tonnes of oil equivalent - A metric measure used to quantify general energy requirements for practical purposes, an alternative to the barrel of oil equivalent. usually taken as representing 10,000 kilocalories net. Ton (t) A term covering a variety of measures: The metric tonne (1000 kg) The long ton (2240 lbs) The short ton (2000 lbs). The metric tonne is the one increasingly used. W Watt - The basic unit of electrical power, defined as one joule per second. Water Drive In a porous rock, as gas is withdrawn from the reservoir, water expands into the region formerly occupied by the gas as pressure is released. This often has the result of trapping gas so that it cannot be produced, thus reducing recovery from the reservoir. Water drive is not a problem with a D epletion Drive Reservoir . See also Reservoir. Water Gauge A measure often used to express the pressure of gas in distribution systems, using water instead of mercury. Distribution systems normally operate at about 300mm (12 inches) water gauge (i. e. 300mm above atmospheric pressure). For comparison, atmospheric pressure is a little above 10metres of water. See also Gauge Pressure. U.S. Energy Information Administration - EIA - Independent Statistics and Analysis NAAQS: National Ambient Air Quality Standards NAICS ( North American Industry Classification System ): A coding system developed jointly by the United States, Canada, and Mexico to classify businesses and industries according to the type of economic activity in which they are engaged. NAICS replaces the Standard Industrial Classification (SIC) codes. Name plate: A metal tag attached to a machine or appliance that contains information such as brand name, serial number, voltage, power ratings under specified conditions, and other manufacturer supplied data. Naphtha: A generic term applied to a refined or partially refined petroleum fraction with an approximate boiling range between 122 degrees and 400 degrees Fahrenheit. Naphtha-type jet fuel: A fuel in the heavy naphtha boiling range having an average gravity of 52.8 degrees API, 20 to 90 distillation temperatures of 290 degrees to 470 degrees Fahrenheit, and meeting Military Specification MIL-T-5624L (Grade JP-4).It is used primarily for military turbojet and turboprop aircraft engines because it has a lower freeze point than other aviation fuels and meets engine requirements at high altitudes and speeds. Note: Beginning with January 2004 data, naphtha-type jet fuel is included in Miscellaneous Products . Naphthas: Refined or partly refined light distillates with an approximate boiling point range between 122 and 400 degrees Fahrenheit. Blended further or mixed with other materials, they make high-grade motor gasoline or jet fuel. Also, used as solvents, petrochemical feedstocks. or as raw materials for the production of town gas. National Association of Regulatory Utility Commissioners (NARUC): An affiliation of the public service commissioners to promote the uniform treatment of members of the railroad, public utilities, and public service commissions of the 50 states, the District of Columbia, the Commonwealth of Puerto Rico, and the territory of the Virgin Islands. National Defense Authorization Act: The federal law, enacted in 1994 and amended in 1995, that required the Secretary of Energy to prepare the Baseline Report. National priorities list: The Environmental Protection Agencys list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The list is based primarily on the score a site receives from the Environmental Protection Agency Hazard Ranking System. The Environmental Protection Agency is required to update the National Priorities List at least once a year. National Rural Electric Cooperative Association (NRECA): A national organization dedicated to representing the interests of cooperative electric utilities and the consumers they serve. Members come from the 46 states that have an electric distribution cooperative. National Uranium Resource Evaluation (NURE): A program begun by the U. S. Atomic Energy Commission (AEC) in 1974 to make a comprehensive evaluation of U. S. uranium resources and continued through1983 by the AECs successor agencies, the Energy Research and Development Administration (ERDA), and the Department of Energy (DOE).The NURE program included aerial radiometric and magnetic surveys, hydrogeochemical and stream sediment surveys, geologic drilling in selected areas, geophysical logging of selected bore holes, and geologic studies to identify and evaluate geologic environments favorable for uranium. Native gas: Gas in place at the time that a reservoir was converted to use as an underground storage reservoir in contrast to injected gas volumes. Native load (electric): The end-use customers that the Load-Serving Entity is obligated to serve. NERC definition Natural gas: A gaseous mixture of hydrocarbon compounds, the primary one being methane . Natural gas field facility: A field facility designed to process natural gas produced from more than one lease for the purpose of recovering condensate from a stream of natural gas however, some field facilities are designed to recover propane, normal butane, pentanes plus, etc. and to control the quality of natural gas to be marketed. Natural gas gross withdrawals: Full well-stream volume of produced natural gas, excluding condensate separated at the lease. Natural gas hydrates: Solid, crystalline, wax-like substances composed of water, methane, and usually a small amount of other gases, with the gases being trapped in the interstices of a water-ice lattice. They form beneath permafrost and on the ocean floor under conditions of moderately high pressure and at temperatures near the freezing point of water. Natural gas lease production: Gross withdrawals of natural gas minus gas production injected on the lease into producing reservoirs, vented, flared, used as fuel on the lease, and nonhydrocarbon gases removed in treating or processing operations on the lease. Natural gas liquids production: The volume of natural gas liquids removed from natural gas in lease separators, field facilities, gas processing plants, or cycling plants during the report year. Natural gas marketed production: Gross withdrawals of natural gas from production reservoirs, less gas used for reservoir repressuring, nonhydrocarbon gases removed in treating and processing operations, and quantities vented and flared. Natural gas marketer: A company that arranges purchases and sales of natural gas. Unlike pipeline companies or local distribution companies, a marketer does not own physical assets commonly used in the supply of natural gas, such as pipelines or storage fields. A marketer may be an affiliate of another company, such as a local distribution company, natural gas pipeline, or producer, but it operates independently of other segments of the company. In States with residential choice programs, marketers serve as alternative suppliers to residential users of natural gas, which is delivered by a local distribution company. Natural gas plant liquids (NGPL): Those hydrocarbons in natural gas that are separated as liquids at natural gas processing, fractionating, and cycling plants. Products obtained include ethane. liquefied petroleum gases (propane. normal butane. and isobutane ), and natural gasoline. Component products may be fractionated or mixed. Lease condensate and plant condensate are excluded. Note: Some EIA publications categorize NGPL production as field production, in accordance with definitions used prior to January 2014. Natural gas plant liquids (NGPL) production: The extraction of gas plant liquids constituents such as ethane. propane. normal butane. isobutane. and natural gasoline. sometimes referred to as extraction loss. Usually reported in barrels or gallons, but may be reported in cubic feet for purposes of comparison with dry natural gas volumes. Natural Gas Policy Act of 1978 (NGPA): Signed into law on November 9, 1978, the NGPA is a framework for the regulation of most facets of the natural gas industry. Natural gas processing plant: Facilities designed to recover natural gas liquids from a stream of natural gas that may or may not have passed through lease separators andor field separation facilities. These facilities control the quality of the natural gas to be marketed. Cycling plants are classified as gas processing plants. Natural Gas Used for Injection: Natural gas used to pressurize crude oil reservoirs in an attempt to increase oil recovery or in instances where there is no market for the natural gas. Natural gas used for injection is sometimes referred to as repressuring. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Om du fortsätter att surfa på webbplatsen godkänner du användningen av cookies på denna webbplats. Se vår användaravtal och sekretesspolicy. Slideshare använder cookies för att förbättra funktionalitet och prestanda, och att ge dig relevant reklam. Om du fortsätter att surfa på webbplatsen godkänner du användningen av cookies på denna webbplats. Se vår sekretesspolicy och användaravtal för detaljer. Explore all your favorite topics in the SlideShare app Get the SlideShare app to Save for Later even offline Continue to the mobile site Upload Login Signup Double tap to zoom out NATURAL GAS DEHYDRATION Share this SlideShare LinkedIn Corporation copy 2017
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