To correct another kneejerk comment far above about Exxon-Mobil, the prices of crude are set by demand and the Commodities Market. West Texas crude often is used as the indicator; it was $101.4 today. Middle East oil is a bit lower (not the cheapest to refine).

In Venezuela, Exxon-Mobil was just one operator. They objected to yielding a 60% stake to PDVSA (the Venezuelan company) and thought about suing, but now have sold their interests to Repsol (a Spanish-Argentine company) which agreed to Venezuelan terms.
Others who have agreed to terms are Royal Dutch Shell, Petrobras (Brazi), and China National Petroleum Co.
Total and Enl refused and are now nationalized.