From my understanding, Venezuela's oil reserves are larger and were discovered first. So what lead to the Western nations to invest so heavily in Saudi Arabia instead of Venezuela? Especially for the United States, given their closer geographic proximity to Venezuela.
Edit: I'm writing a paper on Oil in Latin America. I'm not asking you to do my homework for me. In all my research, nothing seems to answer this question that seems like a fairly obvious one to ask.
Well, the middle east was a hotspot ever since the 40's. Even as far back as 1946, superpowers were trying to control the region. In that year, the Soviet union occupied Iran, but eventually left without much trouble.
In WW2, the Axis were particularly interested in controlling the Iranian oil fields. Germany was particularly short of oil, and even the oil fields in eastern Europe were not enough to provide for the Third Reich, so there was always the question of Iran and it's significance.
Add a cold war backdrop, with bloody, unofficially backed coups, and you have a recipe for a center of oil. The role of Israel played a part, as the Arab nations in OPEC managed to use oil as a diplomatic weapon of sorts in the 70's, by effectively sanctioning the rest of the world by driving up oil prices, most notably America for their backing of Israel.
In sum, the middle easy became the center of oil for a number of reasons, of which the Cold War was a significant factor.
Popular media plays a part too. With recent conflicts in the middle east, and oil being used to finance war, it is only natural people and news headlines draw attention to the middle east being a powerhouse pumping out tons of oil. This is a misconception and a generalization of what is geographically, a very wide area.