during a conversation with journalists,

they asked Hugo Chávez why he was certain that the United States was interested in acting against Venezuela. His response was this:

Hugo Chavez:
"Look, here's the current story, I'll tell you the most relevant reason. Right here, right here is the largest oil reserve in the world, there's crude oil in Venezuela for more than 100 years, the United States is running out of its own. The strongest reason the United States wants to install a submissive government here, to the empire, as they've had for a long time, is Venezuelan crude."
Source: Empty Mind