Global oil reserves rose by 31 billion barrels to 1,653 billion barrels in 2011
Iraq added 28 billion bbls and Russia, Brazil, and Saudi Arabia all increased reserves by 1 billion bbls. Proved reserves remain concentrated in OPEC which controls 72% of the world’s oil reserves, the highest proportion since 1998. Overall, the long-term trend is the world continues to add more reserves than it uses while the global R/P ratio stands at 54.2 at the end of 2011.
Proved reserves of oil 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 geological conditions.
We have provided a detailed explanatory note on reserves clarifying current definitions and terminology. Reserves in the Review include gas condensate and natural gas liquids (NGLs) as well as crude oil.
The data series for proved oil 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, under accounting rules contained in the Statement of Recommended Practice. 'Accounting for Oil and Gas Exploration, Development, Production and Decommissioning Activities' (UK SORP) or 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.
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. It is 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 oil reserves. R/P ratios for the region and the world are depicted in the chart above and the Energy charting tool.
There is a time series of crude oil reserves, which can be found in the Excel workbook. Data are measured in thousand million barrels.
The estimates have been compiled using a combination of primary official sources, third-party data from the OPEC Secretariat, World Oil, Oil & Gas Journal and an independent estimate of Russian and Chinese reserves based on information in the public domain. Canadian oil sands 'under active development' are an official estimate. Venezuelan Orinoco Belt reserves are based on the OPEC Secretariat and government announcements.