Abandoned Well	A well no longer in use, whether dry, inoperable or no longer productive.
Acre of Feet	Unit of volume; one acre of producing formation one foot thick. One acre- foot equals 7,758 barrels 325,829 gallons, or 43,560 cubic feet.
Allowable	Amount of oil or gas which a well, leasehold or field may produce per month under proration orders of the Texas Railroad Commission (RRC).
Assignment	The legal instrument whereby Oil and Gas Leases, Royalty Interests, or Overriding Royalty interests are assigned/conveyed.
Associated Reservoir	Oil and gas reservoir with a gas cap. Gas production from these reservoirs is generally restricted in order to preserve the gas cap energy thereby increasing ultimate recovery.
Basic Sediment and Water (BS&W)	Impurities and water contained in the fluid produced by an oil well.
Bbl, Barrel	In the energy industry, a barrel is 42 U.S. gallons measured at 60 degrees Fahrenheit.
BCF	The abbreviation for billion cubic feet of gas. (see “cubic foot of gas”)
BHP	The abbreviation for bottom-hole pressure.
Blowout Prevention	Casinghead equipment that prevents the uncontrolled flow of oil, gas and mud from the well by closing around the drill pipe or sealing the hole.
BOPD	The abbreviation for barrels of oil per day.
BTU, British Thermal Unit(s)	The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit under standard conditions of pressure and temperature.
Casing	Pipe cemented in the well to seal off formation fluids or keep the hole from caving in.
Casinghead Gas	Gas found naturally in oil and produced with the oil.
Christmas Tree	The system of pipes, valves, gauges, and related equipment that is located on the well at ground level and that controls the flow of gas and other petroleum products produced from the well.
Condensate (also called Lease Condensate)	Liquid hydrocarbons separated from gas production.
Crude Oil	Liquid petroleum as it comes out of the ground as distinguished from refined oils manufactured out of it.
Cubic Foot of Gas or Standard Cubic Foot of Gas	As a unit of volume, 1,728 cubic inches. As applied to water, 7.48 gallons. As applied to natural gas, the volume of gas which, when saturated with water vapor at 60 degrees F and at a pressure of 30 inches of mercury occupies one cubic foot of volume
Discovery Well	The first oil or gas well drilled in a new field. The discovery well is the well that is drilled to reveal the actual presence of a petroleum-bearing reservoir. Subsequent wells are development wells.
Disposal Well	Well used for disposal of saltwater into an underground formation.
Dissolved Gas	Commonly referred to as a solution gas. (Refer to solution gas)
Division Order	A schedule of owners and their decimal share in revenues of the well derived from the sale of oil and gas.
Downstream	This term is used in describing operations performed after those at a point of reference (generally the sales meter).
Dry Gas	Natural gas that does not have a significant content of liquid hydrocarbons or water vapor.
Dry Hole	Any well that fails to discover oil or gas in paying quantities.
Electric Logs	Recording that indicates the well's rock formation characteristics by different responses to electric current.
Exploratory Well	Any well drilled for the purpose of securing geological or geophysical information to be used in the exploration or development of oil, gas, geothermal, or other mineral resources, except coal and uranium, and includes what is commonly referred to in the industry as “slim hole tests,” “core hole tests,” or “seismic holes”.
Extraction Loss	The reduction in volume and energy content of natural gas resulting from the removal of natural gas liquid constituents.