Oil prices have fallen 70% since hitting a record $147.27 a barrel in July, which means in just five months, crude has given up all the price gains it made in the past four years.

After such a wrenching plunge, many analysts believe the outlook for the "black gold" remains bleak – and in the short term it certainly is. In the long run, however, dwindling supplies, resurgent demand, and a lack of investment will cause crude oil to double, triple, or even quintuple in price over the next few years.