But that's changed. U.S. oil prices are now just $1 or $2 a barrel cheaper than Brent.
"The economics don't entirely work for U.S. crude to be traded everywhere in the world," said Brian Scheid, a senior editor at Platts.
There are also logistical hurdles keeping U.S. oil from straying too far from home. Due to the longstanding export ban, America's Gulf Coast doesn't currently have the equipment in place needed to load the giant supertankers that other countries typically use to ship oil long distances, according to Nilofar Saidi, a crude oil market analyst at ClipperData. Smaller ships can be used on voyages to Latin America and Europe, but aren't ideal for far-flung places like East Asia.
Columbia's Bordoff thinks it will take time to fix that situation. "Given the market situation today, there's going to be caution about large-scale infrastructure investments," he said.