The top ten largest oil companies based on their 2012 reserves are:
1. Saudi Aramco | 260,000,000,000 bbl
2. National Iranian Oil Company | 138,000,000,000 bbl
3. Iraq National Oil Company | 116,000,000,000 bbl
4. Pemex | 102,000,000,000 bbl
5. Petróleos de Venezuela | 99,000,000,000 bbl
6. Abu Dhabi National Oil Company | 92,000,000,000 bbl
7. National Oil Corporation (Libya) | 41,000,000,000 bbl
8. Nigerian National Petroleum Corporation | 36,000,000,000 bbl
9. Qatar Petroleum | 15,000,000,000 bbl
10. Sonatrach | 12,000,000,000 bbl
Together the top ten companies held a total of 911,000,000,000 bbl in reserves in 2012.
With the current price of oil, the monetary value of these 10 companies’ reserves is $94,744,000,000,000.
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Just how much oil is that?
With the current price of oil, the monetary value of #1 Saudi Aramco’s reserves tops $27,040,000,000,000. That’s roughly double the US national debt.

The #2 National Iranian Oil Company has the oil reserve equivalent of 27x Iran’s GDP in 2012.