interesting article on nationalized oil companies (via the economist):
Yet Big Oil is pretty small next to the industry's true giants: the national oil companies (NOCs) owned or controlled by the governments of oil-rich countries, which manage over 90% of the world's oil, depending on how you count. Of the 20 biggest oil firms, in terms of reserves of oil and gas, 16 are NOCs. Saudi Aramco, the biggest, has more than ten times the reserves that Exxon does.
Saudi Aramco's proved reserves alone could keep the world supplied for several decades. But it is only exploiting ten of its 80 or so fields, so will be able to pump at the present rate for about 70 years even if it never discovers another drop of oil.