Total proved reserves of natural gas are generally taken to be those quantities that geological and engineering information indicates with reasonable certainty can be recovered in the future from known reservoirs under existing economic and operating conditions.
The data series for proved natural gas reserves in this year’s Review does not necessarily meet the definitions, guidelines and practices used for determining proved reserves at company level, for instance as published by the US Securities and Exchange Commission nor does it necessarily represent BP's view of proved reserves by country. Rather the data series has been compiled using a combination of primary official sources and third-party data.
Although every effort is made to come up with a consistent series for reserves based on a common definition, in reality different countries use different methodologies and the data have varying levels of reliability.
R/P ratios represent the length of time that those remaining reserves would last if production were to continue at the previous year's rate. They are calculated by dividing remaining reserves at the end of the year by the production in that year.
Reserves-to-production (R/P) ratios are available by country and feature in the table of gas reserves. R/P ratios for the region and the world are depicted in the chart above the Energy charting tool and World Energy app.
There is a time series of natural gas reserves, which can be found in the Excel workbook. Data are measured in billion cubic metres.