Why do British and American countries use barrels? In fact, it mainly follows the previous traditional practices, and this history will be attributed to the earliest oil companies.

The first two places in the world that produce industrial oil are rich in wine, both of which are famous in China. People who produce industrial oil always use barrels to fill the crude oil that has just been produced. 1870, Rockefeller established the standard oil company. They use their own vats of wine and deliver them to their homes. 1 barrel is 42 gallons. The U.S. government has adopted a standard acceptable to both British and American businessmen, that is, it follows the standard formulated by Rockefeller family standard oil company and stipulates that 42 gallons is 1 barrel.

This standard unit of crude oil measurement "barrel"-3.7854L per gallon (made in America), so 1 barrel is about159L-has become the most used crude oil trading unit in the world.

There are two main methods to calculate oil production, supply and marketing in the world: one is to calculate by volume and express it in barrels or liters; The other is by weight, expressed in tons. It is customary to use tons to calculate the annual output and consumption of oil, and barrels to calculate the daily output, consumption and export of oil. The density of oil produced in different regions is different, and the weight of a barrel is slightly different. At present, when the international oil industry converts the weight and volume of crude oil, it generally takes Saudi 34-degree light crude oil as the benchmark. This crude oil is equivalent to 7.33 barrels per ton. Unit of volume: 1 bbl)=42 American gallon =0. 159 cubic meter 1 American gallon =3.785 liters 1 British gallon =4.546 liters 1 cubic meter = 1000 liters.