List of countries by proven oil reserves

Proven oil reserves are those quantities of petroleum which, by analysis of geological and engineering data, can be estimated with a high degree of confidence to be commercially recoverable from a given date forward from known reservoirs and under current economic conditions. Some statistics on this page are disputed and controversial — different sources (like OPEC, CIA World Factbook and oil companies) give different figures.

Source: Wikipedia — List of countries by proven oil reserves (CC BY-SA 4.0)