The nuclear deal reached with Iran intends to lift some sanctions; including those on oil trading. Iran has the fourth largest global oil reserves and has stockpiled billions of barrels, which it can now sell. Experts believe that Iran could load 500,000 barrels a day onto an already flooded market. So what if the price drops to $30 per barrel, it is $15,000,000 per day Iran does not currently get and begs the question: What does OPEC do?
The price of $30 is roughly half of what oil has been trading at, a big hit for the likes of the Saudis to take. Do they drop production to try to force the price up, or do they keep production up in the hope the price rises? The last option could force prices even lower. Then what do the likes of Russia, Nigeria and Venezuela do?
In the meantime cheap oil allows it to be used wastefully, well, more wastefully than it currently is - an environmental disaster.
We'll see.