Publications

Survey of Energy Resources 2007

Natural Gas - Definitions

Natural gas is a mixture of hydrocarbon and small quantities of non-hydrocarbons that exists either in the gaseous phase or is in solution in crude oil in natural underground reservoirs, and which is gaseous at atmospheric conditions of pressure and temperature.

Natural gas liquids (hydrocarbons that exist in the reservoir as constituents of natural gas but which are recovered as liquids in separators, field facilities or gas-processing plants) are discussed in Chapter 2 - Crude Oil and Natural Gas Liquids.
Proved amount in place is the resource remaining in known natural reservoirs that has been carefully measured and assessed as exploitable under present and expected local economic conditions with existing available technology.

Proved recoverable reserves are the volume within the proved amount in place that can be recovered in the future under present and expected local economic conditions with existing available technology.

Estimated additional amount in place is the volume additional to the proved amount in place that is of foreseeable economic interest. Speculative amounts are not included.

Estimated additional reserves recoverable is the volume within the estimated additional amount in place that geological and engineering information indicates with reasonable certainty might be recovered in the future.

Production - where available, gross and net (marketed) volumes are given, together with the quantities re-injected, flared and lost in shrinkage (due to the extraction of natural gas liquids, etc.).

Consumption - natural gas consumed within the country, including imports but excluding amounts re-injected, flared and lost in shrinkage.

R/P (reserves/production) ratio is calculated by dividing proved recoverable reserves at the end of 2005 by production (gross less re-injected) in that year. The resulting figure is the time in years that the proved recoverable reserves would last if production were to continue at the 2005 level.

As far as possible, natural gas volumes are expressed in standard cubic metres, measured dry at 15o C and 1 013 mb, and the corresponding cubic feet (at 35.315 cubic feet per cubic metre).

NOTE:
The quantifications of reserves and resources presented in the tables that follow incorporate, as far as possible, data reported by WEC Member Committees. Such data will reflect the respective Member Committees' interpretation of the above Definitions in the context of the reserves/resources information available to them, and the degree to which particular countries' terminology and statistical conventions are compatible with the WEC specifications.