Yes.. oil is a finite resource, it is getting harder and harder to obtain.. and there are LESS major oil discovery every year hence the global reserves are actually shrinking every year. It will be harder and harder and more expensive to obtain the liquid gold from the ground in time to come.
Fracking is a relatively new technology, and they are reviving OLD wells to squeeze out whatever remaining oil, which was not tapped last time. The bakken formation is not a new discovery, it has been tapped since the 1900's. Each fracking well lifetime is only about 12-16 months as they are squeezing out the last toothpaste from the tube. It will be matter of time all the oil is gone from the bakken formation but it will take at least 5-10 years
Energy efficiency and alternative power is slowly replacing oil, but they are still expensive and not cost effective. And even if enough alternative energy to displace oil consumption. Oil is not only used for fuel, it is in your everyday products from plastics, to fertilizers, food products, cosmetics etc.. and these are not replaceable anytime soon.
There are 'green' alternatives of course which is made from corn, soybean or palm oil, but increasingly these will be used for food in the future, as by 2050 the earth will add a another 2 billion population. By then food, fuel and fertilizer will be a scarcity.
Thus looking at the extreme long term view, my super long term portfolio is concentrated on food (palm oil), fuel (OnG), alternative energy and fertilizers (phosphate), which has limited reserves and have no scientific ways to manufacture it.

I believe water will be very precious in future. Aside from the much-dreaded water rationing in Malaysia, California and Brazil also face water shortage.