But when necessary, such volume is converted to a volume of oil of equivalent enthalpy of combustion. Other terms are used when discussing only oil.
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. In other circumstances, it can be important to include gas in production and consumption figures. Type in unit symbols, abbreviations, or full names for units of length, area, mass, pressure, and other types. Outside of the oil industry, the unit Mbbl megabarrel can sometimes stand for one million barrels.
Normally, gas amount is measured in standard cubic feet or cubic metres for volume as well as in kg or Btu which don't depend on pressure or temperature. Cubic metre is the basic volume unit in the International System. Barrel This unit is used in North America for crude oil or other petroleum products. 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.
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. Nearly all other countries use the metric system.
Some of these barrels would originally have been used for other products, such as beer, fish, molasses or turpentine. The gallon whiskey barrel was the most common size used by early oil producers, since they were readily available at the time.