With white on the following map you can see how many billion barrels of oil each country has, and with yellow what share of the global oil market each country controls. I guess the numbers need to be updated because Venezuela is now a bit richer than Saudi Arabia in oil reserves. But the map is good to give you a rough idea of the global oil market. Note that only the richest countries in oil reserves are included, which means that countries with significant oil prodution but low oil reserves are not included i.e. Norway. That’s why you get a market share of less than 65% if you add the market share of all countries.