National Balancing Point (NBP)

A notional point on the UK Transco pipeline through which all gas in the country is deemed to flow. Used as the point of reference for UK gas pricing.

National Energy Board

Canadian regulatory body that oversees inter-provincial gas trade and pipelines. Located in Alberta.

Native gas

Natural gas in place in a producing reservoir when the reservoir is converted into a gas-storage reservoir.

Natural gas

A naturally occurring mixture of hydrocarbon compounds and small quantities of various non-hydrocarbons existing in the gaseous phase or in solution with crude oil in natural underground reservoirs at reservoir conditions. The principal hydrocarbons usually contained in the mixture are methane, ethane, propane, butanes, and pentanes. Typical non-hydrocarbon bases that may be present in reservoir natural gas are carbon dioxide, helium, hydrogen sulphide, and nitrogen. Under reservoir conditions, natural gas and the liquefiable portions thereof occur either in a single gaseous phase in the reservoir or in solution with crude oil and are not distinguishable at that time as separate substances. The principal constituent is methane (CH4) and is the simplest of hydrocarbons.

Natural-gas heating value

The amount of thermal energy released by the complete combustion of 1 cf of natural gas. Higher Heating Value (HHV) or Gross Heating Value (GHV) assumes that the water vapour produced in the combustion process is condensed to liquid. Net Heating Value (NHV) assumes the vapour produced in the combustion process stays in the gaseous phase.

Natural gas liquids (NGLs)

Liquid hydrocarbons, such as ethane, propane, butane, pentane and natural gasoline, extracted from field gas.

Natural-gas processing

1) the purification of field gas at gas-processing plants (or gas plants), or the fractionation of mixed natural gas liquids (NGLs) to natural gas products to meet specifications for use as pipeline quality gas. Gas processing includes removing liquids, solids, and vapours, absorbing impurities and odourising; 2) the process of separating NGLs by absorption, adsorption, refrigeration or cryogenics from a stream of natural gas.

Natural-gas producer

A natural gas producer is generally involved in exploration, drilling and refinement of natural gas.

Natural-gas resource base

An estimate of the amount of natural gas available, based on the combination of reserves, contingent resources and prospective resources. Reserves may include proved, probable and possible commercial reserves. Contingent resources include recoverable quantities from known accumulations that are not commercial. Prospective resources are those quantities of petroleum that are estimated to be recoverable from undiscovered accumulations.

Natural-gas storage

A means of providing a reserve of natural gas supplies to meet the seasonal demands of natural gas customers.

Natural-gas transportation system

The pipeline transportation system used to accept and transport natural gas.

Net capacity (shipping)

The number of tonnes of cargo that a vessel can carry when loaded in salt water to her summer freeboard marks. Also called cargo-carrying capacity, cargo deadweight and useful deadweight.

Net gas

Total produced natural gas times net working interest in natural gas production.

Net tonnage

The carrying capacity of vessels as prescribed by government regulations and determined by measuring the cubic contents of the space intended for revenue earning.

Netback price

The effective price to the producer of natural gas at a defined point, based on the market price for the natural gas less the charges for delivering the natural gas from the defined point to market.


In North America, an order slip to an interstate pipeline, stating the volume of gas a supplier seeks to transport over a fixed period of time. Most nominations are now submitted electronically through pipeline Electronic Bulletin Board/Internet websites.

Non-associated gas

Free natural gas not in contact with, or dissolved in, crude oil in a reservoir. LNG projects require large, proved reserves of non-associated gas to insure supply over long contract terms.

Non-firm purchase

Purchase of a commodity such as natural gas on an as-available basis.

No-notice service

A pipeline delivery service that allows customers to receive gas on demand without making prior nominations to meet peak service needs and without paying daily balancing and scheduling penalties.


A contractual breach.