M. King Hubbert’s prescient prediction of peak oil in the United States worked for five decades until 2010 noted Mark Sooby, managing director for Bank of America Merrill Lynch.

“But now, we are way off track,” Sooby told attendees at Hart Energy’s DUG Eagle Ford Conference and Exhibition in San Antonio on Oct. 15. “So what happened?” he asked. “Well, unconventionals happened.”

What started as a technique to develop natural gas has now spread to natural gas liquids and crude oil, thanks to the price differential between dry gas and ...