Glossary on Natural Gas

British thermal unit (BTU): Quantity of heat required to raise the temperature of 1 lb of water through 1 degree Fahrenheit.
Conservation: Regulation of gas production from a reservoir in order to prolong its life and hopefully recover a larger quantity of the gas in place: re-injection of associated gas for future use.
Conversion: The process whereby appliances, furnaces, or boilers are modified so that they can burn a different fuel than that for which they were originally designed.
Cubic foot: The standard unit used to measure quantity of gas (at atmospheric pressure) 1 cubic foot = 0.0283 cubic metres.
Distribution line: A pipeline that deliver natural gas to end users.
Dry natural gas: Natural gas which is low in associated liquids; mostly methane.
Extraction: The removal of a substance from a mixture by the use of a selective solvent.
Feedstock: The supply of crude oil, natural gas liquids or natural gas to a refinery or petrochemical plant or the supply of some refined fraction of intermediate petrochemical to some other process.
Flaring: Burning off of gas produced in association with oil which, for technical or economic reasons, cannot be re-injected or shipped ashore.
Gathering lines: A pipeline that transports gas from a current production facility to a transmission line or main.
Gas cap: A layer of natural gas above the oil in an oil reservoir.
Gas field: A field containing natural gas but no oil.
Gas grid: A network of pipelines used to distribute gas to industrial and domestic consumers.
Gas injection: The process whereby separated associated gas is pumped back into a reservoir for conservation purposes or to maintain the reservoir pressure.
Gas pipeline: A pipeline used to transport gas between two places either offshore or onshore.
Hydrocarbons: Compounds containing only the elements hydrogen and carbon. They may exist as solids, liquids or gases.
Ignition point: Temperature to which a substance can be heated before it will burn.
Liquefied natural gas (LNG): natural gas that has been liquefied by refrigeration or pressure in order to facilitate storage or transport, it generally consists mainly of methane.
Liquefied petroleum gas (LPG): A mixture of light hydrocarbons derived from oil-bearing strata which is gaseous at normal temperatures but which has been liquefied by refrigeration or pressure in order to facilitate storage or transport: it generally consists mainly of propane and butane. Sometimes known as condensate.
Maximum allowable operating pressure (MAOP): The maximum pressure at which a pipeline or segment of a pipeline may be operated.

div style="text-align: justify;">Natural gas liquids (NGL): Liquid hydrocarbons found in association with natural gas.

Non-associated gas: Natural gas from gas and condensate wells, in which there is little or no crude oil.
Octane Number: A measure of the resistance of a fuel to pre-ignition (“knock”) when burned in an internal combustion engine.
Odorant: A substance such as a mercaptan that is added to natural gas and natural gas liquids when used as fuel (which are normally odourless) to give them a characteristic smell and thus enable them to be detected.
Offshore: The adjective applied to any structure or activity located or carried out at sea as opposed to on land (onshore).
Onshore: The adjective applied to any structure or activity located or carried out on land as opposed to at sea (offshore).
Petrochemical: An intermediate chemical derived from petroleum’ hydrocarbon liquids or natural gas, e.g. ethylene, propylene, benzene, toluene and xylene.
Petroleum: A generic name for hydrocarbons, including crude oil, natural gas liquids, natural gas and their products.
Pig: A piece of equipment that is inserted into pipeline and is carried along by the flow of oil or gas: used to clean or monitor the internal condition of the pipeline or to mark an interface between two different products.
Pipeline: A pipe through which oil, its products, or gas is pumped between two points, either offshore or onshore.
Processing plant: Special plant installed on a production platform or at a pipeline terminal to separate gas, oil and water from mixture containing some or all of these components: also called treatment or separation plant.
Producing horizon: Rock from which oil or gas is produced.
Production drilling: Drilling of wells in order to bring a field into production.
Production licence: A licence to produce oil or gas in a particular area issued to a company by the governing state.
Production platform: A platform from which development wells are drilled and which carries all the associated processing plant and other equipment needed to maintain a field in production.
Production tubing: The pipe in a production well through which oil or gas flows from the reservoir to the surface; also known as the production string.
Production well: A well used to remove oil or gas from a reservoir.
Proven field: An oil and/or gas field whose physical extent and estimate reserves have been determined.
Proven Reserves: The estimated quantities of hydrocarbons which geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known oil and gas reservoir under existing economic and operating conditions.
Purging: Cleansing of processing equipment, or pipelines. Vessels must be purged of noxious gases by sweeping them air before removing manways or entering them for cleaning or inspection. Pipelines must be purged of material. E.g. water, before they are placed into service to carry crude or natural gas.
Racking Pipe: The act of placing lengths of pipe in an orderly arrangement in the derrick.
Recoverable reserves: That proportion of the oil and/or gas in a reservoir that can be removed using currently available technology.
Sour gas: Natural or associated gas with a high sulphur content.
Source rock: the rock in which oil or natural gas originates.
Sweet gas: Natural gas with low sulphur content.
Town gas: The traditional type of locally manufactured gas fuel originally made from coal.
Transmission line: A pipeline that transports gas from gathering or storage facility to a distribution center, storage facility, or large volume customer.
Wellhead: The control equipment fitted to the top of a well casing, incorporating outlets, valves, blowout preventers, etc.
Wet natural gas: Natural gas which contains large amounts of associated liquids.