I do not know how high it could get, but I know that it will not be as great as it used to be. Everyone around the world is going for green energy these days, which means even though we are still stuck with oil and gas for now, it will not be like that forever, eventually there will be a period in human history where there won't ever be a need for oil ever again, that will take few decades at least that is for sure, but between solar, wind, hydro and few others that I forgot, that is going to be something that is definitely worth looking into.

Plus entry to those business is not as hard as oil is, if you want to drill your own oil out of ground and sell it that is going to take you a lot of money, whereas if you just buy some solar panels and put it on top of your roof that is going to get you started, few thousand at most for a start is a good benefit of this business as well.