Oil is an important commodity to have, but owning much oil does not equal wealth. There are many factors that contribute to the wealth of a country - have a read on the Wealth of Nations by Adam Smith.

China has cheap labour cost and production capacity that USA cannot match. Europe has its strategic position with a lot of ports and economic routes besides agricultural climate. But saying that USA is wealthy because of its oil sites is just a small part of the story. Middle East has a lot of oil reserves as well and you don't see them "ruling" the world.