Non-self-propelled marine vessel used as cargo tankers, equipment and supply carriers, crane platforms and support and accommodation bases in offshore drilling, and as submarine pipe-laying vessels.


As the standard unit of measurement of liquids in the petroleum industry, it contains 42 U.S. standard gallons. Abbreviated to "bbl."

Barrels of Oil Equivalent (BOE)

The volume of natural gas that when burned produces the same amount of heat as a barrel of oil (6,000 cubic feet of gas equals one barrel of oil). BOE = gas volumes divided by six and added to crude and natural gas volumes.

Base oils

Feedstock for lubricant production from the residual part of crude oil.

Basement Rock

The ancient rock that lies below sedimentary strata; it does not contain oil or gas.


The firm base rock to which is anchored the geological structure of interest to petroleum geologists.


An aromatic hydrocarbon present to a minor degree in most crude oils. Some important products manufactured from benzene are styrene, phenol, nylon and synthetic detergents.


The technique of combining two or more petroleum liquids to produce a product with specific characteristics.


A geographical area that includes several separate oil and gas license tracts.

Block Leases

A contract with diverse owners of separately leased oil and gas tracts that enables an oil company to drill one or two test wells instead of one well per tract.

Block Number

The numerical designation assigned to offshore lease and license tracts, or subdivisions of the tracts.

Blow Molding

A plastics-forming process that uses compressed air to shape the final product by expanding it to fit the mold.


A pump system installed to maintain or increase pressure in pipelines so that liquids and gases keep flowing.


Barrels of oil per day; barrels per day.


Bi-axially oriented polypropylene production.

Bottom Out

To reach the objective depth in drilling a well.

Bottom-hole Assembly

The components, together as a group, that make up the lower end of the drill string – comprising the drill bit, drill collars, drill pipe and ancillary equipment.


The heavy portions, or fractions, of a crude oil that do not vaporize during distillation; the accumulation of sediments, mud and water in the bottoms of lease tanks.

Bunker fuel oil

A heavy residual fuel oil used by ships.


A butane derivative that is one of the most widely used raw materials used in the manufacture of synthetic rubber.


Refers usually to a mixture of isobutane and normal butane. A flammable, gaseous hydrocarbon. Used as fuel.


A substance obtained incidentally during the manufacture or production of some other substance.


A pipe connected around a valve or other control mechanism in a flow line for the purpose of maintaining flow during adjustments or repair work.