Oil barrels

Petroleum ... is a naturally occurring, yellow-to-black liquid found in geologic formations beneath the Earth's surface, which is commonly refined into various types of fuels. ... The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. [Petroleum. Wikipedia] A drum is a cylindrical container... Drums are also called barrels in common usage. ... International standard size. A 200-litre drum (known as a 55-gallon drum in the US and a 44-gallon drum in the United Kingdom) is a cylindrical container with a nominal capacity of 200 litres (55 US or 44 imp gal). ... The drums are typically made of steel with a ribbed outer wall to improve rigidity and for rolling. The lids can be welded or secured with a head gasket and bolt ring. ... They are commonly used for transporting oils, fuels, chemicals, and dry goods. [Drum (container). Wikipedia] An oil barrel (abbreviated as bbl) is a unit of volume whose definition has not been universally standardized. In the United States and Canada, an oil barrel is defined as 42 US gallons, which is about 159 liters or 35 imperial gallons, and it can also be defined in those units, depending on the context. Oil companies that are listed on American stock exchanges typically report their production in terms of volume and use the units of bbl, Mbbl (one thousand barrels), or MMbbl (one million barrels). [Barrel (unit). Wikipedia]