About 77% of crude oil has already been discovered, and 30% of it has been used so far. Between 1859 and 1968, 200 billion barrels (31 km³) of oil were used, and since then oil production has stabilized to 22 billion barrels (3.5 km³) per year. It is estimated that oil reserves will become scarce by 2050s.

Most of oil is concentrated in the Near East — around 41%. North America, Russia, and Antarctica are also rich in crude oil.