It's great to have low prices, but when the price for oil drops to $20/bbl, companies here (but not the Middle East countries) will stop drilling for new sources, wells currently in production will be shut down, and even refineries may quit. It's what happens when they can't sell the product at a price high enough to stay in business. The we'll be buying all our petroleum products from Saudis, Iranians, and ISIS.
The Saudis, for example, can make money when crude oil is selling for under $10/bbl, so they'll own the market at that price. OTOH, when all the American drilling crews have left the oil patch for non-oil jobs, and wells and refineries are closed (or sold to Iran by the Muslim-in-Chief), it will be very expensive to re-start them. And we will pay for it...in many unpleasant ways.
They were sitting down long before 30 a Barrel. Gulf of Mexico had 59 rigs drilling for oil December 2014. Today there are 20, with more shutting down in the next three months. Oil companies are not turning their 7% profit, but rather a loss. So they do not pay some one to drill for them. Lots more shut down in the Dakotas with more to come. Over 100,000 people laid off, mostly jobs that pay 50K or more a year.
Saudi is pumping over quota as is much of OPEC as they want our drilling out of business. The USA just helped then buy lifting sanctions on Iran and letting them flood the market with more oil.
Very soon we will be dependent on the Middle east again for all our fuel.