The race to export U.S. shale oil overseas is about to get fierce, with at least nine proposed terminals angling for a piece of a very limited pie.

Within 18 months, new pipelines opening in the nation's most prolific shale basin promise to carry an added 2 million barrels of oil a day to the Gulf Coast. But the extra crude will arrive at a time when existing terminals in the Corpus Christi area can already offer only about 300,000 barrels a day of unused capacity.

Meanwhile, some of the terminals proposed are being designed to load a supertanker every other day, each capable of carrying 2 million barrels. The result: It's likely only one or two new terminals are needed, with the edge going to companies such as Nexus pipeline partner Enbridge Inc., whose Freeport, Texas, effort could be fed by two pipelines it already owns interests in.

"Anyone can build a terminal," said Chief Executive Officer James Teague of Enterprise Products Partners, one of the first companies to export oil from the U.S., in a conference call last month. "But it's what's behind that terminal that determines its success."

Or in other words, success in the terminal business is as much about securing the barrels as it is about shipping them out.

U.S. oil exports have soared to nearly 2 million barrels a day since a near four-decade moratorium was lifted in late 2015, just as shale production kicked into high gear. Both the Nexus and Rover pipelines crossing Northeast Ohio connect with pipelines that can carry output from the region's Marcellus and Utica shale fields to the Gulf of Mexico.

Trafigura Group Ltd. and other trading houses have jumped at the opportunity to send those supplies to Europe and Asia.

But there's been a problem: Pipeline shortages, particularly in the prolific Permian Basin, have limited how much oil makes it to the coast. Now, anticipating an end to those woes with three major new pipelines expected to open in 2019, several companies — including Trafigura — are lining up with plans to provide terminals that can take advantage of the change.

Industry analysts have predicted that exports will double by 2020 given increased export capacity and growing shale production.

Enbridge hasn't released many details on its proposal for Freeport, which is about 175 miles northeast of Corpus Christi.

The lion's share of crude exports now leave from around Houston given the expansive network of inbound pipelines, storage tanks and dock space in the Houston Ship Channel. But that activity can also prohibit new growth, some say, with concerns about congestion limits.

That makes Corpus Christi, a steadily growing export hub, an attractive option. Many new Permian pipelines slated to come online are ending up there, pushing an infrastructure bottleneck from the shale play south. That ultimately builds a strong case for new terminals to be constructed.