Oil and gas experts are closely watching the Permian Basin in 2018. That's hardly surprising, considering it's the largest and fastest-growing energy play in the United States. But some are worried that it may be growing too fast.The Permian Basin has grown crude oil production from 1.5 million barrels per day (bpd) entering 2014 to over 3.1 mbp today -- and that doesn't include natural gas (it's the second-largest gas play in the country) or other petroleum liquids.