A company involved in virtually all aspects of the oil and gas industry including exploration, production, transportation, refining and marketing. These companies are also referred to as major oil companies.

A fractional working interest

Heavy steel pipe used to seal off fluids from the hole or to keep the hole from caving in.

A fitting attached to the top (head) of the casing in a producing oil or gas well (usually at or just above ground level). The casinghead regulates the flow of oil or gas, helps separate oil from gas, allows the pumping of oil from an oil well, and facilitates periodic cleaning out of the well. See Christmas tree

Natural gas produced along with crude oil from oil wells (as opposed to gas produced from gas wells). Also known as associated gas

 Stub attached to a check disclosing well name, month of production, price received and total volumes produced.

A device placed in a flow line to restrict the flow of oil and gas. Chokes are commonly used to measure flow rates in producing wells.

A complex assemblage of valves, controls, fittings, gauges, and pipe connections at the top of the casing of an oil or gas well. The Christmas tree controls the flow of oil and gas from the well. The silhouette of the apparatus can vaguely resemble a decorated Christmas tree, hence the moniker.

Compressed Natural Gas, which is used as a fuel for smaller vehicles.

Completing a well. The phase which comes after the drilling of a successful well, which includes all of the work required to ready the well for commercial production.