Alot of people are going to talk about how "oil isn't going anywhere" and "we'll be using oil for decades", which is technically true, but I think as soon as Electric Cars takes off (and I think we're at the point where it's more than 10 years away), oil is going to go into a steep decline because passenger cars are such a large part of the demand. Oil is very supply/demand sensitive: a demand reduction of a few percent can send prices tumbling and knock out lots of marginal producers. Once an industry is in decline, investment dries up pretty quick. The low cost producers like the middle east will still be around just because they can profitably pump for so low, but the higher cost producers are going to have an extremely tough time. Gas will be around for a while longer because we need it to balance renewables, but I see the same thing: if someone can figure out low cost storage, demand will dry up pretty quick.
One analogy I would use is coal: coal will also be around for several decades still, but no one in their right mind would try to get into it now, because it clearly has no future.
Ultimately if you still want to get into this field, try to stick with some aspect that will can transfer over to other industries. Or just go into tech. It's a growing field that pays well and had good job growth.
