Barrel (unit)

"bbl" redirects here. For other uses, seeBBL (disambiguation).

Ale casks at a brewery in the UK. These arefirkins,each holding 9 imperial gallons (41 L) or a quarter of a UK beer barrel.

Abarrelis one of severalunits of volumeapplied in various contexts; there aredry barrels,fluid barrels(such as theU.K. beer barrelandU.S. beer barrel),oil barrels,and so forth. For historical reasons the volumes of some barrel units are roughly double the volumes of others; volumes in common use range approximately from 100 to 200 litres (22 to 44 imp gal; 26 to 53 US gal). In many connections the termdrumis used almost interchangeably withbarrel.

Since medieval times the termbarrelas a unit of measure has had various meanings throughout Europe, ranging from about 100 litres to about 1,000 litres. The name was derived in medieval times from theFrenchbaril,of unknown origin, but still in use, both in French and as derivations in many other languages such asItalian,Polish,andSpanish.In most countries such usage is obsolescent, increasingly superseded bySI units.As a result, the meaning of corresponding words and related concepts (vat, cask, keg etc.) in other languages often refers to a physical container rather than a known measure.

In the international oil market context, however, prices inUnited States dollarsper barrel are commonly used, and the term is variously translated, often to derivations of theLatin/Teutonicrootfat(for examplevatorFass).

In other commercial connections, barrel sizes such as beerkegvolumes also are standardised in many countries.

Dry goods in the US

See also:Dry goods

• US dry barrel:7,056cubic inches(115.6litres;3.3US bushels)
  • Defined as length of stave28+1⁄2in (72 cm), diameter of head17+1⁄8in (43 cm), distance between heads 26 in (66 cm), circumference of bulge 64 in (160 cm) outside measurement; representing as nearly as possible 7,056 cubic inches; and the thickness of staves not greater than4⁄10in (10 mm)(diameter ≈ 20.37 in or 52 cm). Any barrel that is 7,056 cubic inches is recognized as equivalent. This is exactly equal to 26.25US dry gal.
• US barrel for cranberries5,826cubic inches(95.5litres;2.7US bushels)
  • Defined as length of stave28+1⁄2in (72 cm), diameter of head16+1⁄4in (41 cm), distance between heads25+1⁄4in (64 cm), circumference of bulge58+1⁄2in (149 cm) outside measurement; and the thickness of staves not greater than4⁄10in (10 mm)(diameter ≈ 18.62 in or 47.3 cm). No equivalent in cubic inches is given in the statute, but later regulations specify it as 5,826 cubic inches.

Some products have a standard weight or volume that constitutes a barrel:

• Cornmeal,200 pounds (91 kg)
• Cement (includingPortland cement), 4 cubic feet (113 L; 30 US gal) or 376 pounds (171 kg)
• Sugar,5 cubic feet (142 L; 37 US gal)
• Wheat or ryeflour,threeUS bushels(110 L) or 196pounds(89 kg)
• Lime (mineral),280 pounds (127 kg) large barrel, or 180 pounds (82 kg) small barrel
• Butter and cheese in UK, 224 pounds (102 kg)
• Salt, 280 pounds (130 kg)

Fluid barrel in the US and UK

Fluid barrels vary depending on what is being measured and where. In the UK a beer barrel is 36imperial gallons(43US gal;164L). In the US most fluid barrels (apart from oil) are 31.5 US gallons (26 imp gal; 119 L) (half ahogshead), but a beer barrel is 31 US gallons (26 imp gal; 117 L).The size of beerkegsin the US is based loosely on fractions of the US beer barrel. When referring to beer barrels or kegs in many countries, the term may be used for the commercial package units independent of actual volume, where common range for professional use is 20–60L,typically aDINorEuro kegof 50 L.

History

See also:English wine cask unitsandEnglish brewery cask units

Richard III,King of Englandfrom 1483 until 1485, had defined the wine puncheon as a cask holding 84wine gallonsand a winetierceas holding 42 wine gallons. Custom had made the 42 gallon watertight tierce a standard container for shipping eel, salmon, herring, molasses, wine, whale oil, and many other commodities in the English colonies by 1700. After theAmerican Revolutionin 1776, American merchants continued to use the same size barrels.

Oil barrel

"Blue barrel" redirects here. For the plant, seeBlue barrel cactus.

While the barrel as a unit of measurement for oil is 42 U.S. gallons, actual barrels used in industry are typically 55 U.S. gallons or 200 litres internationally.

Definitions

In theoil industry,onebarrel(unit symbolbbl) is aunit of volumeused for measuringoildefined as exactly 42US gallons,approximately 159 liters,or 35imperial gallons.

According to theAmerican Petroleum Institute(API), astandard barrel of oilis the amount of oil that would occupy a volume of exactly 1 barrel (158.99 L) at reference temperature and pressure conditions of 60 °F (15.6 °C) and 14.696psi(1,013.25hPa). This standard barrel of oil will occupy a different volume at different pressures and temperatures. A standard barrel in this context is thus not simply a measure of volume, but of volume under specific conditions. (See also:Standard temperature and pressure#Molar volume of a gas.)

Unit multiples

Oil companies that are publicly listed in the United States typically report their production using theunit multipleskbblorMbbl(one kilobarrel, one thousand barrels) orMMbbl(one million barrels), and occasionally (for wider comprehensive statistics)Gbbl(or sometimesGbl) forgiga-barrel (onebillionbarrels).There is a conflict concerning the units for oil barrels (see§ Definitions and units). For all otherphysical quantities,according to theInternational System of Units,the uppercase letter "M" means "mega-"(" one million "), for example: MHz (one millionhertz,or megahertz) and MB (one millionbytes,orMegabyte). But due to tradition, the Mbbl acronym is used today meaning "one thousand bbl", as a heritage of the roman number "M" for Latin "mille" meaning "one thousand". On the other hand, there are efforts to avoid this ambiguity, and most of the barrel dealers today prefer to use kbbl, instead of Mbbl, mbbl, MMbbl or mmbbl.

The abbreviationsMbblandMMbblrefer to one thousand and one million barrels respectively. These are derived from the Latin "mille", meaning "thousand". This is different from theSIconvention for where "M" stands for "mega" representing million, from the Greek for "large". Outside of the oil industry, the unit Mbbl (megabarrel) can sometimes stand for one million barrels.

Etymology

The first "b" in "bbl" may have been doubled originally to indicate the plural (1 bl, 2 bbl), or possibly it was doubled to eliminate any confusion with bl as a symbol for thebale.Some sources assert that "bbl" originated as a symbol for "blue barrels" delivered byStandard Oilin its early days. However, while Ida Tarbell's 1904 Standard Oil Company history acknowledged the "holy blue barrel", the abbreviation "bbl" had been in use well before the 1859 birth of the U.S. petroleum industry.

Flow rate

Oil wellsrecover not just oil from the ground, but alsonatural gasand water. The termbarrels of liquid per day(BLPD) refers to the total volume of liquid that is recovered.Similarly,barrels of oil equivalentor BOE is a value that accounts for both oil and natural gas while ignoring any water that is recovered. Other terms are used when discussing only oil. These terms can refer to either the production ofcrude oilat an oil well, the conversion of crude oil to other products at anoil refinery,or the overall consumption of oil by a region or country. One common term isbarrels per day(BPD, BOPD, bbl/d, bpd, bd, or b/d), where 1 BPD is equivalent to 0.0292gallons per minute.One BPD also becomes 49.8 tonnes per year.At an oil refinery, production is sometimes reported asbarrels per calendar day(b/cd or bcd), which is total production in a year divided by the days in that year. Likewise,barrels per stream day(BSD or BPSD) is the quantity of oil product produced by a single refining unit during continuous operation for 24 hours.

Burning one tonne of light, synthetic, or heavy crude yields 38.51, 39.40, or 40.90 GJ (thermal) respectively (10.70, 10.94, or 11.36 MW·h), so 1 tonne per day of synthetic crude is about 456 kW of thermal power and 1 bpd of synthetic crude is about 378 kW (slightly less for light crude, slightly more for heavy crude).

Conversion

The task of converting a standard barrel of oil to astandard cubic metreof oil is complicated by the fact that the latter is defined by the API to mean the amount of oil that, at different reference conditions (101.325kPaand 15 °C (59.0 °F)), occupies 1 cubic metre. The fact that the refence conditions are not exactly the same means that an exact conversion is impossible unless the exact expansion coefficient of the crude is known, and this will vary from one crude oil to another.

For a light oil with density of 850 kilogram per cubic metre (API gravityof 35),warming the oil from 59 °F (15 °C) to 60 °F (16 °C) might increase its volume by about 0.047%. Conversely, a heavy oil with a density of 934 kg/m³(API gravity of 20) might only increase in volume by 0.039%. If physically measuring the density at a new temperature is not possible, then tables ofempirical datacan be used to accurately predict the change in density. In turn, this allows maximum accuracy when converting between standard barrel and standard cubic metre. The logic above also implies the same level of accuracy in measurements for barrels if there is a 1 °F (0.56 °C) error in measuring the temperature at time of measuring the volume.

For ease of trading, communication andfinancial accounting,international commodity exchanges often set a conversion factor for benchmark crude oils. For instance the conversion factor set by theNew York Mercantile Exchange(NYMEX) forWestern Canadian Select(WCS) crude oil traded atHardisty, Alberta,Canada is 6.29287 U.S. barrels per standard cubic metre,despite the uncertainty in converting the volume for crude oil. Regulatory authorities in producing countries setstandards for measurement accuracyof produced hydrocarbons, where such measurements affect taxes or royalties to the government. In the United Kingdom, for instance, the measurement accuracy required is ±0.25%.

Qualifiers

A barrel can technically be used to specify any volume. Since the actual nature of the fluids being measured varies along the stream, sometimes qualifiers are used to clarify what is being specified. In the oil field, it is often important to differentiate between rates of production of fluids, which may be a mix of oil and water, and rates of production of the oil itself. If a well is producing 10 mbd of fluids with a 20% water cut, then the well would also be said to be producing 8,000 barrels of oil a day (bod).

In other circumstances, it can be important to includegasin production and consumption figures. Normally, gas amount is measured instandard cubic feetorstandard cubic metres(for volume at STP), as well as inkgorBtu(which do not depend on pressure or temperature). But when necessary, such volume is converted to a volume of oil of equivalententhalpyof combustion. Production and consumption using this analogue is stated in barrels of oil equivalent per day (boed).

In the case ofwater-injectionwells, in the United States it is common to refer to the injectivity rate in barrels of water per day (bwd). In Canada, it is measured in cubic metres per day (m³/d). In general, water injection rates will be stated in the same units as oil production rates, since the usual objective is to replace the volume of oil produced with a similar volume of water to maintain reservoir pressure.

Related kinds of quantity

Outside the United States, volumes of oil are usually reported incubic metres(m³) instead of oil barrels. Cubic metre is the basic volume unit in theInternational System.In Canada, oil companies measure oil in cubic metres, but convert to barrels on export, since most of Canada's oil production is exported to the US. The nominal conversion factor is 1 cubic metre = 6.2898 oil barrels,but conversion is generally done bycustody transfermeters on the border, since the volumes are specified at different temperatures, and the exact conversion factor depends on both density and temperature. Canadian companies operate internally and report to Canadian governments in cubic metres, but often convert to US barrels for the benefit of American investors and oil marketers. They generally quote prices inCanadian dollarsper cubic metre to other Canadian companies, but useUS dollarsper barrel in financial reports and press statements, making it appear to the outside world that they operate in barrels.

Companies on the European stock exchanges report themassof oil intonnes.Since different varieties of petroleum have different densities, however, there is not a single conversion between mass and volume. For example, one tonne of heavy distillates might occupy a volume of 6.1 barrels (970litres;256US gallons). In contrast, one tonne of crude oil might occupy 6.5 barrels (1,030 litres; 273 US gallons), and one tonne of gasoline will require 7.9 barrels (1,260 litres; 332 US gallons).Overall, the conversion is usually between 6 and 8 barrels (954 and 1,270 litres; 252 and 336 US gallons) per tonne.

History

The measurement of an "oil barrel" originated in the earlyPennsylvaniaoil fields.TheDrake Well,the first oil well in the US, was drilled in Pennsylvania in 1859, and an oil boom followed in the 1860s. When oil production began, there was no standard container for oil, so oil and petroleum products were stored and transported in barrels of different shapes and sizes. Some of these barrels would originally have been used for other products, such as beer, fish, molasses, or turpentine. Both the 42-US-gallon (159 L) barrels (based on the old English wine measure), thetierce(159 litres) and the 40-US-gallon (150 L)whiskeybarrels were used. Also, 45-US-gallon (170 L) barrels were in common use. The 40 gallon whiskey barrel was the most common size used by early oil producers, since they were readily available at the time.

Around 1866, early oil producers in Pennsylvania came to the conclusion that shipping oil in a variety of different containers was causing buyer distrust. They decided they needed a standard unit of measure to convince buyers that they were getting a fair volume for their money, and settled on the standard winetierce,which was two gallons larger than the standard whisky barrel. TheWeekly Register,anOil City, Pennsylvanianewspaper, stated on August 31, 1866 that "the oil producers have issued the following circular":

Whereas, It is conceded by all producers of crude petroleum on Oil Creek that the present system of selling crude oil by the barrel, without regard to the size, is injurious to the oil trade, alike to the buyer and seller, as buyers, with an ordinary sized barrel cannot compete with those with large ones. We, therefore, mutually agree and bind ourselves that from this date we will sell no crude by the barrel or package, but by the gallon only. An allowance of two gallons will be made on the gauge of each and every 40 gallons in favor of the buyer.

And by that means, King Richard III's English wine tierce became the American standard oil barrel.

By 1872, the standard oil barrel was firmly established as 42 US-gallons.The 42 gallon standard oil barrel was officially adopted by the Petroleum Producers Association in 1872 and by the U.S. Geological Survey and the U.S. Bureau of Mines in 1882.

In modern times, many different types of oil, chemicals, and other products are transported in steeldrums.In the United States, these commonly have a capacity of 55 US gallons (208 L) and are referred to as such. They are called 200 litre or 200 kg drums outside the United States. In the United Kingdom and its former dependencies, a 44-imperial-gallon (200 L) drum was used, even though all those countries now officially use the metric system and the drums are filled to 200 litres. Thus, the 42 US-gallon oil barrel is a unit of measure, and is no longer a physical container used to transport crude oil, as most petroleum is moved inpipelinesoroil tankers.In the United States, the 42 US-gallon size of barrel as a unit of measure is largely confined to the oil industry, while different sizes of barrel are used in other industries. Nearly all other countries use themetric system.

See also

• 55 gallon drum
• Barrel
• Barrel of oil equivalent
• English brewery cask units
• English wine cask units
• Imperial units
• List of unusual units of measurement
• Petroleum
• Petroleum pricing around the world
• Standard Barrel Act For Fruits, Vegetables, and Dry Commodities
• United States customary units
• Units of measurement