Energy Statistics Manual - University Of California, Berkeley

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Oil1What is Oil ?General informationPetroleum is a complex mixture of liquid hydrocarbons, chemical compoundscontaining hydrogen and carbon, occurring naturally in underground reservoirs insedimentary rock. Coming from the Latin petra, meaning rock, and oleum,meaning oil, the word “petroleum” is often interchanged with the word “oil”. Broadlydefined, it includes both primary (unrefined) and secondary (refined) products.Crude oil is the most important oil from which petroleum products aremanufactured but several other feedstock oils are also used to make oil products.There is a wide range of petroleum products manufactured from crude oil. Manyare for specific purposes, for example motor gasoline or lubricants; others are forgeneral heat-raising needs, such as gas oil or fuel oil.The names of the petroleum products are those generally used in Western Europeand North America. They are commonly used in international trade but are notalways identical to those employed in local markets. In addition to these oils, thereare others which are “unfinished” oils and will be processed further in refineries orelsewhere.Oil supply and use in industrialised economies are complex and involve bothenergy use and non-energy use. As a result, the indications of use given below canonly be guides to general practice and not rigid rules. Annex 1 provides fullexplanations of the processes and activities mentioned within the questionnaire.Oil is the largest traded commodity worldwide, either through crude oil or throughrefined products. As a consequence, it is essential to collect data as complete,accurate and timely as possible on all oil flows and products. Although oil supplycontinues to grow in absolute terms, its share in global total energy supply has beendecreasing, from over 45% in 1973 to around 35% in recent years.Specific information related to the joint questionnaireThe Oil Questionnaire covers oils processed in refineries and the petroleumproducts made from them. All sources of supply and the uses of the oils are to beincluded as well as their calorific values.Crude oil is not the only feedstock to a refinery. Other primary or secondary oils canbe used as feedstock: NGL, refinery feedstocks, additives and oxygenates and otherhydrocarbons such as shale oil or synthetic crude oil from tar sands (see Table 4.1).A whole range of petroleum products are derived from crude oil, varying from lightproducts such as liquefied petroleum gas (LPG) and motor gasoline to heavier onessuch as fuel oil.69

4OilTable 4.1 Primary versus Secondary OilCrude oilPRIMARYOILNatural gas liquidsPRODUCTSOther hydrocarbonsSECONDARY PRODUCTSAdditives/blending componentsRefinery feedstocksINPUTS TO REFINERYSECONDARYRefinery gasTransport dieselEthaneHeating and other gasoilLiquefied petroleum gasesRes. fuel: low-sulphur contentNaphthaRes. fuel: high-sulphur contentAviation gasolineWhite spirit SBPGasoline type jet fuelLubricantsUnleaded gasolineBitumenLeaded gasolineParaffin waxesKerosene type jet fuelPetroleum cokeOther keroseneOther productsOILPRODUCTSA full description of these primary and secondary oil products and theirspecifications are given in Annex 2. These specifications are important, becausethere are different oil product names in use for certain products in the world, forexample “stove-oil” and “mazout”; their specifications should be obtained fromsuppliers so that the oils can be reported using the product names in the OilQuestionnaire.EssentialPetroleum is a complex mixture of liquid hydrocarbonsoccurring naturally in underground reservoirs.70

Oil24What Units are Used to Express Oil?General informationLiquid fuels can be measured by their mass or volume. Within each of thesemeasurements, several units are used in the oil industry: The most widely used unit of mass (weight) to measure oil is the metric ton (ortonne). For instance, tankers in the oil industry are often described on the basisof their capacity in tonnes, where an ultra large crude carrier (ULCC) is definedas being able to carry over 320 000 tonnes. The original unit for most liquid and gaseous fuels is volume. Liquids can bemeasured by the litre, the barrel, or the cubic metre. A common example of theuse of volume as the unit of measurement is in the price of oil, quoted in dollarsper barrel.As liquid fuels can be measured by their mass or their volume, it is essential to beable to convert one into the other. In order to make this conversion, the specificgravity or density of the liquid is needed.Because crude oil contains a wide range of hydrocarbons from the lightest to theheaviest, the characteristics, including the density, of individual crude oils varygreatly. Similarly, the density of the different petroleum products varies substantiallybetween the products.The density can be used to classify petroleum products from light to heavy, wherefor example LPG is considered light at 520 kg/m3 while fuel oil is a heavy productat over 900 kg/m3.Please note: many countries and organisations use the tonne of oil equivalent(toe) when publishing energy balances. The toe unit which is based on calorificproperties is used to compare oil with other energy forms and should not beconfused with the mass measurement in tonnes.Specific information related to the joint questionnaireThe units employed in the questionnaire are thousand metric tons. When other unitsof mass are used, data are to be converted to metric tons using conversion factorsas found in Annex 3.For volume to mass conversion, specific densities (see Section 3) should be used forboth crude oil and petroleum products, including gases (for example refinery gas);however, in cases where these are not available, please use the average factorshown in Annex 3. Figures should be whole numbers without decimal places.EssentialOil data are reported in thousand metric tonsin the questionnaire. Figures should be whole numberswithout decimal places.71

43OilHow to Make the Conversionfrom Volume to Mass?General informationThe oil industry in different parts of the world uses different units of measurement.For example, in Europe the metric ton is commonly accepted as the unit ofmeasurement, while in the United States, the volume unit barrel is the unit of choice.In Japan, volume is also used for measuring oil supply and demand; however, thestandard unit is the cubic metre.As so many different units, both volume and mass, are used in the world, it isessential to be able to convert them into a common unit for purposes ofcomparison. The oil industry internationally uses mainly barrels (bbl) as itsreference unit. For certain flows such as production and demand, it is barrels perday (b/d) which is commonly used.As mentioned above, to convert from mass into volume or vice versa, the specificgravity or density of the oil must be known. Without going into too much technicaldetail, a few terms need to be explained in order to understand oil conversion factors.Density is defined as mass per unit volume, i.e. tonne/barrel. The specific gravity isthe relative weight per unit volume (or density) of a given substance compared to thatof water. The density of water is 1g/cm3. Motor gasoline, for example, has a lowerdensity as it is much lighter for the same volume. The specific gravity of motor gasolineis therefore smaller than 1. Since volume changes with changes in temperature, dataon specific gravity are reported with a reference to a specific temperature (forpetroleum, the reference is usually 15 degrees Celsius). Moreover, specific gravity isoften quoted as a percentage, e.g. a specific gravity of 0.89 is shown as 89.The term API gravity (a standard adopted by the American Petroleum Institute) iscommonly used to express the specific gravity of petroleum.Nota bene: API gravity is defined as: ( 141.5 / 60o specific gravity at 60o F ) – 131.5.The result is an arbitrary scale for measuring gravity, expressed in degrees API,where the lighter a compound is, the higher its degree of API gravity. For example,what are considered light crudes are generally greater than 38 degrees API, whilethose with less than 22 degrees API are labelled as heavy crude oils.Specific gravity and API gravity move in opposite directions. API gravity moves in thesame direction as energy content per tonne, i.e. the higher the API gravity, thehigher the energy content per tonne, whereas specific gravity moves in the samedirection as energy content per unit volume.Specific informationThe Oil Questionnaire requires oil data to be reported in metric tons. It is thereforeoften necessary for national statisticians to convert volumetric data into metric tons.National statisticians should, to the extent possible, obtain information from thereporting enterprises on how quantities of crude oil and petroleum products haveto be converted from volume to metric tons. This is particularly important for some72

Oil4of the oil products in gaseous form (e.g. refinery gas, ethane, LPG) which have tobe expressed in mass terms.Density and gross calorific values of selected petroleum products can be found in Annex 3.The following table offers an example of converting volume (in this case given in barrelsper day) to mass (in metric tons) for two different months (January and February).Table 4.2 ImportsConversion from Volume to Mass – An ExampleReported dataNumber ofin barrels per day days/month(volume)DensityVolume/massmass/volume tonne/barrel(average) conversion factorConverted datain metric tons(mass)Crude oil1020310.135691/0.13569 7.37 (1020x31)/7.37 4290Motorgasoline546280.118061/0.11806 8.47(546x28)/8.47 1805EssentialIn the questionnaire please convert liquid fuels fromvolume to mass by using appropriate conversionfactors based on actual density.4Oil FlowsGeneral informationThe flow of oil from production to final consumption is complex owing to the varietyof elements in the chain. The diagram below provides a simplified view of this flow,covering supply of inputs to the refinery, supply of finished products to the end-user,and the petrochemical flows which interact in the process. These main links in thesupply chain will be further discussed below.Figure 4.1 Simplified Flow Chart for Oil73

4OilProduction of primary and secondary products, trade, stocks, energy sector,transformation, and final consumption are the main elements to be known in orderto have a comprehensive view of the flow of oil in a country.Specific information related to the joint questionnaireThe Oil Questionnaire consists of six tables. The nature of each table is as follows: Table 1:Supply of Crude Oil, NGL, Refinery Feedstock, Additives and OtherHydrocarbons Table 2A: Supply of Finished Products Table 2B: Deliveries to the Petrochemical Sector Table 3:Gross Deliveries by Sector Table 4:Imports by (country of) Origin Table 5:Exports by (country of) Destination Table 6:Inputs to Autoproducer Electricity and Heat GenerationIt is essential that the figures reported in each table are correctly totalled and thatthe totals in the different tables are consistent with each other where a logicalrelationship exists. These table relationships are illustrated in the following diagram:Figure 4.2 Table Relations within the Oil QuestionnaireImports Total ImportsTable 1:PrimaryProductsSupplyTable 2A:SecondaryProductsSupplyElectricityand HeatQuestionnaireTable 6bElectricityand HeatQuestionnaireTable 9d - 9f74Exports Total ExportsGross Inland Deliveries(observed)Gross Inland Deliveries(observed)Inputs to Gross Electricityand Heat ProductionInputs to AutoproducerElectricity and Heat GenerationTable 4:Imports by OriginTable 5:Exports by DestinationTable 2B:Deliveries to thePetrochemical SectorTable 3:Gross Deliveries by Sector Transformation Energy Distribution Losses Total Final ConsumptionTable 6:Inputs to AutoproducerElectricity andHeat Generationper Plant Type

Oil4The following totals have to be consistent between the various tables: Products Transferred as Refinery Feedstocks in Table 1 should correspond tototal Products Transferred in Table 2A. The total of Direct Use in Table 1 shouldcorrespond to the total of Primary Product Receipts in Table 2A. Imports by Origin in Table 4 should be summed, and the sum should bereported under Total Imports in Table 1 and Table 2A. Exports by Destination in Table 5 should be summed, and the sum should bereported under Total Exports in Table 1 and Table 2A. Total Gross Inland Deliveries in Table 2B should correspond to Gross InlandDeliveries (observed) in Table 2A. Backflows from Petrochemical Sector toRefineries in Table 2B should correspond to Backflows from PetrochemicalIndustry in Table 1. Gross Inland Deliveries in Table 3 should correspond to Gross Inland Deliveries(observed) in Table 2A.All of the oil entering the refinery should be balanced by total gross production ofmanufactured products plus any declared losses. So the following check applies:Refinery Intake Observed (Table 1) Gross Refinery Output (Table 2A) Refinery Losses (Table 1).In addition, within the oil processes and activities, there are reclassifications of oilproducts in which the name of the product changes. For example, a quantity of oilimported as “gas oil” may be used as a “feedstock” and reported under each ofthe names in different tables of the questionnaire.The corresponding checks on the consistency of the amounts reported are describedbelow. Specific issues affecting reporting and definitions of flows are also described.EssentialPlease remember the interrelationships between the tablesin the questionnaire. Key totals should be consistent5Oil SupplyThe oil supply chain is fairly complex, as several types of feedstock are inputs torefineries, and the resulting output is a wide variety of products with many uses.Moreover, the petrochemical industry is a specific case where oil products are usedas feedstocks and oil by-products are returned for further processing. The followingparagraphs will first describe these three portions of the supply chain, namely:supply of crude oil, supply of finished products, and flows of thepetrochemical industry. Information on trade and stocks common to the supplyof crude oil and finished products follows the explanations of the petrochemicalindustry.75

4OilSupply of crude oil, NGL, refinery feedstocks,additives and other hydrocarbonsGeneral informationA flow chart of the various feedstocks from production to refinery input is shown inthe diagram below. This flow chart is voluntarily simplified in order to give an overallview of the supply chain for crude oil, NGL, refinery feedstocks and other inputs.Figure 4.3 Supply of Crude Oil, NGL, Refinery Feedstocks, Additives and Other HydrocarbonsFrom OtherSourcesExportsDirect UseStock BuildIndigenousProductionRefineryImportsBackflows fromPetrochemicalIndustryStock DrawPetrochemicalIndustryProductsTransferredA number of the flows illustrated above require further explanation:Indigenous Production: Before describing the production process of crude oil, it isnecessary to mention that oil production has two meanings, depending on whetherreferring to primary or secondary products. For primary products, IndigenousProduction of crude oil, natural gas liquids and condensates refers to the processof extracting these oils from the earth. In the case of secondary products, RefineryOutput refers to the production of finished products at a refinery or blending plant(see section below on Supply of finished products).Crude oil can be produced from different locations, onshore or offshore fields orfrom different types of wells, in association with natural gas or not. Any gasextracted from associated oil wells may be flared, vented, reinjected or form part ofnatural gas production (see Chapter 3 on Natural Gas).When crude oil is produced from the well, it is a mixture of oil, water, sediment anddissolved gases (methane, ethane, propane, butane and pentanes). In the firstinstance, all gases are separated from the oil/water mixture. The gases areextracted because of their higher value and readily marketable state, such aspropane and butane which are liquefied petroleum gases (LPG). In a later stage,the sediment and other unwanted substances are removed in treatment plants.76

OilFigure 4.4 4Simplified Flow Chart for Indigenous ProductionAssociatedGasTreatmentExtraction ofCrude Oil andAssociated GasSeparationAnnual nding Products from Outsidethe Refinery SectorAdditives/OxygenatesOther Inputs not already includedin energy balancese.g. tar sands, orimulsionOtherHydrocarbonsThe gases are separated in a wellhead separation plant from onshore wells; fromoffshore wells, this happens through a separator on the platform. The methane willform the constituent of natural gas, while the other constituents form the naturalgas liquids (NGL). Natural gas liquids, however, can also be produced inconjunction with natural gas.Crude oil is very diverse; its characteristics can vary widely. Economically, the mostimportant characteristics are its specific gravity and the sulphur content, as these willbe instrumental in determining the price of the crude oil.To complete the supply balance, other inputs such as additives, oxygenates andother hydrocarbons also need to be included in the production data. Additives andoxygenates are those substances (usually non-hydrocarbon compounds) which areadded to fuels to improve their properties, e.g. oxygenates increase the amount ofoxygen in motor gasoline.In the Other Hydrocarbons category are included the production of products suchas emulsified oils (e.g. orimulsion) and synthetic crude oil from tar sands. Thisproduct category also covers shale oil, liquids produced from the coal liquefactionprocess, hydrogen and other such products.Refinery Intake is the total amount of oil (including additives, oxygenates and otherhydrocarbons) to have entered the refinery process. Refinery throughput refers tothis intake and the corresponding output of refined products, described below asrefinery gross output in the section Supply of finished products. The differencebetween this intake and output is the losses that occur in the refining process, suchas evaporation during distillation.Specific information related to the joint questionnaireIndigenous Production in Table 1 of the questionnaire should include onlymarketable production of crude oil, NGL, and other hydrocarbons.77

4OilThere are a number of other categories contributing to production in the supply ofproducts to the refinery which are outlined below. For explanations on trade andstock levels and changes, please consult the appropriate sections which follow.From Other Sources: These are oils whose production has been covered in otherfuel balances. For example, the conversion of natural gas into methanol to be usedas a gasoline component, the production of oil from liquefaction of coal or shaleoil production from oil shale. Inputs of these oils should be reported as from OtherSources if the production of the primary energy form is already covered in other fuelbalances, e.g. synthetic oil from coal liquefaction: the production of coal is coveredin the Coal Questionnaire, the inputs into the coal liquefaction plant are in theTransformation Sector of the Coal Questionnaire (Table 1), while the synthetic oilresulting from this process is reported as from Other Sources of OtherHydrocarbons in the Oil Questionnaire.Backflows from Petrochemical Industry are oils returned to the refinery fromprocesses in the petrochemical industry. They are by-products of processingfeedstock oil supplied to the petrochemical enterprises by the refinery. The refinerymay use the backflows as fuel or include them in finished products. Total Backflowsfrom Petrochemical Industry reported in Table 1 should be identical to backflowsreported in Table 2B.Products Transferred are oils which are reclassified under another name. There is acorresponding row in Table 2A in which the amounts to be transferred are reported.The need for reclassification arises when semi-finished products are imported foruse as feedstock in the refinery and therefore appear in the import data shown inTable 2A. The amounts to be used as feedstock are shown as negative quantities inthe Products Transferred row in Table 2A and the total of all products transferred isthen reported as a positive quantity in the Refinery Feedstocks column of Table 1.Refinery Losses are mass differences which appear between the total oil throughput ofthe refinery (reported as Refinery Intake Observed in Table 1) and the total grossproduction of finished products (reported in Table 2A). The losses arise through genuineoil losses and the conversion of refinery statistics used within the refineries to mass units.Direct Use is amounts which do not enter the refinery but enter consumption directly.The “direct use” of crude oil and/or NGL outside refineries must also be reportedin Table 2A so that their subsequent disposal can be accounted for. In this case, anyfigures entered under Direct Use for crude oil and NGL should be equal to thoseshown in Table 2A, Primary Product Receipts.The formula for Refinery Intake (Calculated) is the sum of production, inputs fromother sources, backflows, transfers (as individually mentioned above), and amountsof imports and stock change, after deducting exports and direct use.EssentialIndigenous production concerns marketable productionwithin national boundaries, including offshore production.Refinery intake is the total amount of oilto have entered the refinery process.78

Oil4Supply of finished productsGeneral informationA simplified flow chart of the supply chain from the refinery to the end-user is shownbelow.Figure 4.5 Supply of Finished ProductsCrude oil as it comes out of the ground is a raw material with limited use. Althoughit can be used as a burning fuel, the real potential of crude oil is reached when itis refined into a range of products, which will be useful for specific purposes to thefinal consumer (e.g. gasoline for transportation). The objective of refining is to addvalue to the raw material, as the total of the refined products should be morevaluable than the feedstock.There are many refinery processes used to transform crude oil. The first basicphase, however, in the refinery process is distillation. Crude oil is heated and fedinto a fractionating column at atmospheric pressure, resulting in a separation of thecrude oil into 4-6 broad cuts. Beyond the atmospheric distillation unit are morecomplex units, in which each stream is redistilled to provide a better yield and moreprecise cut of the final products. For more detailed information, please consultAnnex 1, Section 2.Specific information related to the joint questionnaireRefinery Output is reported in Table 2A. There are a number of other categoriescontributing to production in the supply of finished products. These are outlined below.Primary Products Receipts is the row which brings into Table 2A the crude oil andNGL reported as Direct Use on Table 1 so that the disposal can be shown. NGL79

4Oilshould be shown in the NGL column only if it is disposed of as NGL. NGL may beseparated into ethane and LPG before disposal. If so, the gases are reported asprimary product receipts in the corresponding columns and their disposals will becombined with the disposals of the gases produced in the refineries.Gross Refinery Output of products must include any fuel use of the products withinthe refinery (see Refinery Fuel, below). If separate figures for refinery fuel and onlynet refinery production are given, then the refinery fuel must be added to the netproduction to obtain the gross production figure. The more common problem,however, is that production figures are given but no refinery fuel figures areavailable. In this case, it is most likely that the production figures are net. Thestatistician should then check whether all usual petroleum products are reportedand, if not, ask whether the missing products are fuels used by the refinery insupport of its operations and seek estimates of the amounts concerned. An estimateof the magnitude of missing products and/or refinery fuel may be made bycomparing Refinery Intake Observed on Table 1 with total production as reported.Recycled Products are products which are returned after use to recycling plants forcleaning and reprocessing. They are added to the appropriate column in row 3.There are few products in this category. The most notable product is usedlubricating oil which is cleaned for reuse.Refinery Fuel is the fuel used to support refinery operations and does not includeuse for transport of products to consumers. Use of fuels for the production ofelectricity and heat for sale should be included in the refinery fuel figures but alsoseparately reported in the bottom rows of Table 2A and in the tables making up Table 6.Interproduct Transfers cover movements between products which representreclassification of products owing to changes in quality and therefore specification.For example, aviation turbine fuel which has deteriorated or has been spoiled maybe reclassified as heating kerosene. The quantity transferred is shown as a negativequantity in the product column which surrenders the oil, and positive in the productcolumn which receives the oil. It follows that the sum across all products in this rowshould be zero.International Marine Bunkers are deliveries of oils to ships for consumption duringinternational voyages (bunker oils) and represent a special case of flows of oil fromthe country. The oils are used as fuel by the ship and are not part of the cargo. Allships, irrespective of the country of registration, should be included but the shipsmust be undertaking international voyages, that is, their first port of call must be ina foreign country. International marine bunkers statistics should include fueldelivered to naval vessels undertaking international voyages. Care should be takento ensure that data representing oil delivered for international marine bunkers meetthe definition given here and, in particular, exclude bunker oil used by fishing vessels.EssentialRefinery output should be reported as gross, including any fuelsused by the refinery in support of its operations.80

Oil4Petrochemical flowsGeneral informationWhile petroleum products main uses are for their energetic properties, there are anumber of non-energy uses of petroleum, most notably in the petrochemicalindustry. Petrochemicals are chemicals derived from petroleum, and used as thebasic chemical building blocks for a variety of commercial products. Dating backto the early 1920s, the petrochemical industry today is very diverse, supplying theraw materials for the manufacturing of plastics, synthetic fibres and rubbers,fertilisers, pesticides, detergents and solvents. Industries as diverse as textile, food,pharmaceutical, automobile, and paint manufacturing use petrochemicals.Petrochemical feedstocks are created from a number of petroleum products, mainlynaphtha, LPG and ethane.The petrochemical industry, however, is not only a large consumer of petroleumproducts, it is also a producer of petroleum products, as it extracts the necessarycomponents for production of petrochemicals and then returns the by-products tothe refineries or to the market.The flow chart below illustrates the flow scheme between refineries andpetrochemical plants.Figure 4.6 RefineryFeedstockDeliveries to the Petrochemical thaneNaphthaLPGGas/Diesel OilOtherPlasticsNon-energyUseSyntheticRubberand FibreEnergy UsePesticidesPETROCHEMICAL BACKFLOWS(e.g. pyrolysis gasoline)Specific information related to the joint questionnairePetrochemical flows are reported in Table 2B. The details of these flows are outlinedbelow.Gross Deliveries should represent the total quantity of each oil product delivered tothe petrochemical companies for feedstock use. It should not be a “net” flow, thatis, any oils returned to the refinery from the petrochemical companies should notbe subtracted from the deliveries. The feedstock may also cover some or all of thefuel requirements of the industrial process using the feedstock. However, it shouldnot include oils which are used as general purpose fuels unrelated to the process.81

4OilEnergy Use in the Petrochemical Sector should be the amount of the deliveredfeedstock oils used as fuel during their processing. The fuels are some of the byproduct gases obtained from the feedstock oils during processing. The fuel useinformation must come through the petrochemical companies that may be able toprovide it through the refineries if there is joint refining and petrochemicalprocessing on the site.Backflows from Petrochemical Sector are oils returned to the refinery from processesin the petrochemical industry. They are by-products of processing feedstock oilsupplied to the petrochemical enterprises by the refinery. The refinery may use thebackflows as fuel or include them in finished products.EssentialGross deliveries to the petrochemical sector are oil productsused as raw material in the manufacture of petrochemicals.Products returning to the refinery for further processingor blending should be reported as backflows.Imports and exportsGeneral informationOne of the basic economic realities of oil is that it is often found in areas farremoved from the consuming markets. Two-thirds of the reserves of crude oil areeither in the Middle East or in Russia, while almost 90% of the oil is consumed inother areas.This is why oil needs to be shipped from producing zones to consuming regions. Asoil is a liquid and compact form of energy, transportation is made relatively easy.Oil can be transported in tankers, pipelines, railways and trucks, and a vasttransportation network exists between producing and consuming regions.The information required on origins and de

Moreover, specific gravity is often quoted as a percentage, e.g. a specific gravity of 0.89 is shown as 89. The term API gravity(a standard adopted by the American Petroleum Institute) is commonly used to express the specific gravity of petroleum. Nota bene:API gravity is defined as: ( 141.5 / 60o specific gravity at 60o F ) – 131.5.