Glossary

Gas Processing Glossary

Click on a letter below to find a definition for gas processing terms:

A-B | C-D | E-G | H-K | L-M | N-O | P-R | S-Z

10³M³	Abbreviation for one thousand cubic meters.
A-B
Absorption	The process of removing vapors from a stream of natural gas by passing the natural gas through liquids or chemicals which have a natural attraction to the vapors to be removed from the stream.
Acid Gas	The hydrogen sulfide (H₂S) and/or carbon dioxide (CO₂) contained in or extracted from natural gas or other streams.
Adsorption	The process of removing natural gas liquids from a stream of natural gas by passing the natural gas through granular solids which have a natural attraction to the liquids to be removed from the stream.
Atmospheric Pressure	The pressure exerted on the earth by the earth’s atmosphere. A pressure of 760 mm of mercury, 29.92 inches of mercury, or 14.696 psia is used as a standard for some measurements. The various state regulatory bodies have set other standards for use in measuring the legal volume of natural gas that is sold or processed. Atmospheric pressure may also refer to the absolute ambient pressure at any given location.
Barrel	A unit of liquid volume measurement in the petroleum industry that equals 42 U.S. gallons for petroleum or natural gas liquid products, measured at 60 degrees Fahrenheit and at an equilibrium vapor pressure.
Bbl	Abbreviation for barrel.
Bcf	One billion standard cubic feet or one thousand MMcf or one million Mcf.
BG Mix	A liquefied hydrocarbon product composed primarily of butanes and natural gasoline.
BP Mix	A liquefied hydrocarbon product composed primarily of butanes and propane.
Btu	Abbreviation for British Thermal Unit which is the amount of heat necessary to raise one (1) pound of pure water from fifty-nine (59) degrees Fahrenheit to sixty (60) degrees Fahrenheit at a specified constant pressure.
Btu Factor	A numerical representation of the heating value of natural gas which may be calculated or presented to indicate varying relationships (e.g., the number of Btu contained in one standard cubic foot or the number of MMBtu contained in one Mcf of gas. The factor for a given relationship will vary depending upon whether the gas is “dry” or “saturated”.
Butane	A normally gaseous paraffin compound having the chemical formula of C₄H₁₀.
Butane, Normal	see Normal Butane.
C-D
C₁	A standard abbreviation for Methane.
C₂	A standard abbreviation for Ethane.
C₃	A standard abbreviation for Propane.
C₅+	A standard abbreviation for Pentanes Plus (IC₅, NC₅ and C₆+).
C₆+	A standard abbreviation for Hexane Plus.
Calorimeter	An apparatus that is used to empirically determine the heating value of a combustible material.
Carbon Dioxide	A heavy colorless gas having the chemical formula of CO₂, which is commonly referred to as dry ice when in its solid form.
Casinghead Gas	Natural gas that is produced from oil wells along with crude oil.
Cf	A standard abbreviation for Cubic foot.
Chromatograph	An analytical instrument that separates mixtures of substances into identifiable components by means of chromatogophry.
Chromatography	A technique for separating a mixture into individual components by repeated adsorption and desorption on a confined solid bed used for analysis of natural gas and natural gas liquids.
CO₂	A standard abbreviation for Carbon Dioxide.
Compressibility Factor	A factor usually expressed as “z” which gives the ratio of the actual volume of gas at a given temperature and pressure to the volume of gas when calculated by the ideal gas law without any consideration of the compressibility factor.
Condensate	The liquid formed by the condensation of a vapor or gas; specifically, the hydrocarbon liquid separated from natural gas because of changes in temperature and pressure when the gas from the reservoir was delivered to the surface separators. Condensate remains a liquid at atmospheric temperature and pressure.
Cryogenic Plant	A gas processing plant which is capable of producing natural gas liquids products, including ethane, at very low operating temperatures.
Dew Point	The temperature at any given pressure at which liquid initially condenses from a gas or vapor. It is specifically applied to the temperature at which water vapor starts to condense from a gas mixture (water dew point) or at which hydrocarbons start to condense (hydrocarbon dew point).
Dkt	Abbreviation for Decatherm, equivalent to one MMBtu.
Drip Gasoline	Hydrocarbon liquid that separates in a pipeline transporting gas from the well casing, lease separation, or other facilities and drains into equipment from which the liquid can be removed.
Dry Btu	The heating value of a cubic foot of natural gas that does not contain a significant moisture (water) content.
Dry Gas	Natural gas that either (1) does not contain a significant moisture (water) content, or (2) does not contain significant amounts of liquefiable hydrocarbons. Gas in this second definition preferably should be called lean gas.
E-G
EP Mix	A liquefiable hydrocarbon product consisting primarily of ethane and propane.
Ethane	A normally gaseous paraffin compound having the chemical formula of C₂H₆.
Flash Vapors	Gas vapors released from a stream of natural gas liquids as a result of an increase in temperature or a decrease in pressure.
Fractionation	The process of separating a steam of natural gas liquids into its separate components.
FT³	A standard abbreviation for Cubic Foot.
Gal	An abbreviation for one gallon.
Gas Processing	The separation of components by absorption, adsorption, refrigeration or cryogenics from a stream of natural gas for the purpose of making salable liquid products and for treating the residue gas to meet required specifications.
Gj	An abbreviation for gigajoule, equivalent to one thousand megajoules or one billion joules.
GPM	Gallons per Mcf, the number of gallons of a particular component per Mcf.
Gross Heating Value	The heating value measured in a calorimeter when the water produced during the combustion process is condensed to a liquid state. The heat of condensation of the water is included in the total measured heat.
H-K
H₂S	A standard abbreviation for Hydrogen Sulfide.
Heating Value	The amount of heat developed by the complete combustion of a unit quantity of a material. Heating values for natural gas are usually expressed as the Btu per Cf of gas at designated conditions (temperature and pressure) and either on the dry or water saturated basis.
Heavy Ends	The portion of a hydrocarbon mixture having the highest boiling point. Hexanes or heptanes and all heavier hydrocarbons are usually the heavy ends in a natural gas stream.
Hexane Plus or Heptane Plus	The portion of a hydrocarbon fluid mixture or the last component of a hydrocarbon analysis which contains the hexanes (or heptanes) and all hydrocarbons heavier than the hexanes (or heptanes).
High Heating Value	See Gross Heating Value.
Hydrogen Sulfide	A flammable, very poisonous and corrosive gas with a markedly disagreeable odor, having the chemical formula of H₂S that is a contaminant in natural gas and natural gas liquids.
IC₄	A standard abbreviation for Isobutane.
IC₅	A standard abbreviation for Isopentane.
Inerts	Elements or compounds not acted upon chemically by the surrounding environment. Nitrogen and carbon dioxide are examples of inert components in natural gas. Inerts dilute the natural gas and since they do not burn or combust, have no heating value.
Isobutane	A hydrocarbon of the paraffin series having a chemical formula of C₄H₁₀ and having its carbon atoms branched.
Isopentane	A hydrocarbon of the paraffin series having a chemical formula of C₅H₁₂ and having its carbon atoms branched.
Joule	The International System unit of electrical, mechanical, and thermal energy. A unit of electrical energy equal to the work done when a current of 1 ampere is passed through a resistance of 1 ohm for 1 second. A unit of energy equal to the work done when a force of 1 newton acts through a distance of 1 meter.
L-M
Light Ends	The portion of a liquid hydrocarbon mixture having the lowest boiling points which are easily evaporated.
Light Hydrocarbons	The low molecular weight hydrocarbons such as methane, ethane, propane and butanes.
Liquefied Natural Gas	The light hydrocarbon portion of natural gas that is predominantly methane and which has been liquefied.
Liquefied Petroleum Gas	Predominantly propane or butane separately or in mixtures that are maintained in a liquid state under the pressure within the confining vessel.
Liquefiable Hydrocarbons	The components of natural gas that may be recovered as liquid products.
LNG	Abbreviation for Liquefied Natural Gas.
Low Heating Value	See Net Heating Value.
LPG	Abbreviation for Liquefied Petroleum Gas.
Mcf	Abbreviation for one thousand cubic feet. A standard unit for measuring or expressing the volume of a thousand cubic feet of gas for which the pressure and temperature conditions for the standard measurement must be defined.
Methane	The first member of the aliphatic hydrocarbon series having the chemical formula of CH₄. Natural gas is primarily composed of Methane.
Mj	Abbreviation for megajoule, equivalent to one million joules.
MMBtu	One million Btus.
MMcf	One million standard cubic feet or one thousand Mcf.
Mol%	The number of molecules of an inert or hydrocarbon component contained in a sample of natural gas, or natural gas liquid, expressed as a percentage of the total molecules in the sample.
N-O
N₂	A standard abbreviation for Nitrogen.
Natural Gas Liquids	Natural gas liquids are those hydrocarbons liquefied at the surface in field facilities or in gas processing plants and include propane, butane and natural gasoline.
Natural Gasoline	A mixture of hydrocarbons, mostly pentanes and heavier, extracted from natural gas, which meets vapor pressure and other specifications.
NC₄	A standard abbreviation for Normal Butane.
NC₅	A standard abbreviation for Normal Pentane.
Net Heating Value	The heating value measured in a calorimeter when the water produced during the combustion process is not condensed.
NGL	A standard abbreviation for Natural Gas Liquids.
Normal Butane	An aliphatic compound of the paraffin series having the chemical formula of C₄H₁₀ and having all of its carbon atoms joined in a straight chain.
Normal Pentane	A hydrocarbon of the paraffin series having a chemical formula of C5H12 and having all its carbon atoms joined in a straight chain.
O₂	A standard abbreviation for oxygen.
P-R
Pentanes Plus	A hydrocarbon mixture consisting mostly of normal pentane and heavier components.
Pentane, Normal	See Normal Pentane.
Pipeline Condensate	Liquid hydrocarbons that have condensed from gas to liquid as a result of changes in pressure and temperature as gas flows in a pipeline. Pipeline condensate only remains as a liquid under high-pressure conditions and would vaporize at atmospheric pressure.
Plant Products	All liquid hydrocarbons and other products (including sulfur and excluding residue gas) recovered in a gas processing plant.
Pressure Base	The contractual, regulatory or standard ambient pressure at which natural gas is measured or sampled expressed in psia (pounds per square inch absolute).
Propane	A normally gaseous paraffin compound having the chemical formula of C₃H₈.
p.s.i.a.	Abbreviation for Pounds per Square Inch Absolute. Absolute pressure is the sum of Atmospheric Pressure plus Gauge Pressure.
Raw Gas	Natural gas that has not been processed.
Raw Mix Liquids	A mixture of natural gas liquids that has not been fractionated or separated into its various components.
Residue Gas	The portion of natural gas remaining in a gaseous state after recovery of certain components through gas processing.
Rich Gas	Natural gas which, based on its content of liquefiable hydrocarbons, is suitable for processing in a gas plant for recovery of plant products.
S-Z
Saturated BTU	The heating value of natural gas that is saturated with water vapor.
Scf	Abbreviation for one standard cubic foot, a measurement of a gas volume at a contractual, regulatory or standard specified temperature and pressure.
Shrinkage	The reduction in volume and/or heating value of a natural gas stream due to extraction or removal of some of its components.
Sour Gas	Natural gas that has a high concentration of H₂S.
Sulfur	A pale, yellow, non-metallic chemical element that may be found in a gas stream and which needs to be removed or reduced from the gas stream for corrosion control or health or safety reasons.
Theoretical Gallons	The content of liquefiable hydrocarbons in a volume of natural gas determined from tests or analyses of the gas.
Vapor Pressure	The pressure exerted by a liquid when confined in a specified tank or test apparatus.
Wet Gas	Natural gas that contains either (1) a significant amount of liquefiable hydrocarbons, or (2) a significant amount of moisture (water).