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By Luc Cohen
NEW YORK, July 17 (Reuters) - Big U.S. oil refiners along the Gulf of Mexico, which have led an almost charmed life for the past five years, may have to brace themselves for leaner times in the months ahead.
A boom in domestic shale production yielded a gusher of high-quality oil available at discounted prices thanks to an longstanding ban on U.S. crude exports.
Refiners made billions by turning half of that extra supply into products such as gasoline and diesel that could be freely exported to countries including Brazil and Colombia.
More recently, while drillers reel from the collapse in crude prices, refiners such as Valero Energy Corp and Phillips 66 are still riding high on healthy margins, savoring an OPEC-induced surplus of crude while low pump prices revive domestic demand.
But that business may start losing some of its luster in the coming months, according to a Reuters analysis of refining capacity and export data.
Key customers in Latin America, where about half of U.S. fuel exports go, are poised to import less as they finish refinery projects while an expected contraction in regional economic activity saps demand.
Some 300,000 barrels per day of new capacity will come online in Latin America later this year, according to Reuters calculations. That is equivalent to the combined imports by Brazil and Ecuador, two of the biggest buyers of U.S. fuel, in the first four months of the year.
To be sure, struggling economies, such as Venezuela and Brazil, will find it hard to expand or upgrade refineries and will need to keep relying on imports.
Some analysts also say project delays could extend the U.S. exports boom.
Still, the looming slowdown is likely to be on shareholders' minds when refiners report second-quarter earnings next month.
"Refineries used to point to growing exports as underpinning revenue streams. Now they'll say 'this is where we're maintaining rather than growing'," said David Kirsch, managing director of research and advisory at Energy Intelligence Group.
Some Gulf Coast refiners, such as PBF Energy Inc which recently scooped up a big refinery in Louisiana, have built their strategies around the high margin Latin America business.
Over the past decade, the region has become a major importer of U.S.-made fuel. Last year it consumed nearly 2 million barrels per day of U.S. gasoline, diesel and other products - about one eighth of total U.S. production.
Strong economic growth, inadequate refinery investment and in some cases subsidized pump prices have underpinned demand for U.S. exports. A recent set of long-running repairs has sustained the momentum even as the region's economies began to cool with U.S. exports up 17.5 percent in the first four months of the year from a year ago, according to Reuters calculations based on data from the U.S. Energy Information Administration.
Growth may continue for few more months given that some 440,000 bpd of the region's refining capacity is due to shut for maintenance this quarter, double the average for the past five years, according to IIR Energy data made available to Reuters.
However, a trio of refineries is set to bring some 300,000 of new capacity on stream in the fourth quarter potentially denting demand for U.S. exports.
Ecuador is due to finish revamping its 110,000 bpd Esmeraldas refinery in two months; Colombia's state-run Ecopetrol will restart its Reficar refinery in Cartagena in October or November; Brazil's state-owned Petrobras expects to complete the first phase of the ramp-up of its newest refinery, RNEST, in the second half.
"The situation will change with Reficar restarting," said Diego Usme, equities strategist at Ultralat Capital Markets Inc. in Bogota. "It is going to decrease imports of diluents and refined products from the United States."
In addition, the Energy Information Administration expects fuel demand across the region to grow by less than 1 percent this year, down from an average annual rate of 3 percent of the past decade.
Whether this marks the end of the north-to-south export boom or is just a temporary setback is uncertain. If growth in the region picks up, some big consumers may have to turn to imports again.
Mexico, the biggest buyer of U.S. oil products whose state oil firm Petroleos Mexicanos has slashed budgets and suspended ambitious expansion projects, will be the "swing factor," said Vikas Dwivedi, global head of oil and gas strategy at Macquarie Capital.
Brazil, the second-biggest market for U.S. oil products, could also end up importing more.
Its Petrobras, engulfed by a graft scandal and squeezed by low crude prices, last month pushed back major refinery expansion plans by years.
Last week, domestic shortages and stronger demand forced Brazil, to buy extra gasoline.
Editing by Josephine Mason and Tomasz Janowski