According to BP’s Statistical Review of World Energy 2017, Global proved oil reserves in 2016 rose by 15 billion barrels (0.9%) to 1707 billion barrels, which would be sufficient to meet 50.6 years of global production at 2016 levels. The increase came largely from Iraq (+10 billion barrels) and Russia (+7 billion barrels), with small declines (<1 billion barrels) spread across a number of countries and regions. OPEC countries currently hold 71.5% of global proved reserves.
Oil reserves include field condensate and natural gas liquids as well as crude oil. This inclusive approach helps to develop consistency with the oil production numbers published in the Review, which also include these categories of oil. Liquid hydrocarbon fuels from non-hydrocarbon sources, such as ethanol from corn or sugar or synthetic oil derived from natural gas (so-called GTL or gas-to-liquids), are not included in either the reserves or production series.
Total 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. In the absence of replenishment by successful exploration or reserves growth, so-called ‘reserves replacement’, proved reserves would tend to decline over time as production depleted the existing reserve base. However, the tendency has been for proved reserves at the aggregate level to increase over time as reported discoveries, extensions and improved recovery have exceeded production.
47.7% of the proved reserves in 2016 come from the Middle East, 32.5% from North, Central and South America, 9.5% from Europe and Eurasia, 7.5% from Africa and 2.8% from Asia and Pacific. According to BP, Venezuela holds the largest reserves, Saudi Arabia coming 2nd and Canada 3rd.