I'm sorry i don't know how much potential vietnam has for oil, but you are right about it not being likely. If we were there for any finacial gain the money would be in rubber trees, drugs, and ofcourse lyndon b. Johnson had major investments in a company that made hilicopters for the millitary. The official reason we were there was because france asked us to go and we want to maintain our relationships with our allies and make them happy. Ofcourse where is france now?