CALGARY, Alberta (Reuters) - Production from the oil sands will more than triple over the next quarter century, to 5.1 million barrels per day, Canada’s national energy regulator said in a report released on Tuesday.

In a look at energy production and consumption through 2035, the National Energy Board said output from the oil sands, the largest source of U.S. oil imports, will continue to expand from around 1.5 million bpd currently as new mining and thermal projects tap the resources.

The oil sands of northern Alberta are the world’s third biggest crude reserves, behind only Saudi Arabia and Venezuela, but the largest open to private investment.

The NEB said its forecast also assumes oil prices will rise slowly through to 2035, reaching $115 a barrel in 2010 dollars, a level that provides a reasonable profit even for expensive new mining and upgrading projects such as those operated by Suncor Energy Inc, Royal Dutch Shell and Canadian Natural Resources Ltd.

The board also estimates that Canadian oil exports will rise to 5 million bpd by 2035 from about 2 million currently, with most of the additional supply coming from oil sands projects.

However the board cautioned that its forecast assumes markets and infrastructure will be available to handle the additional production. That outlook comes despite a U.S. decision delaying the approval of TransCanada Corp’s Keystone XL pipeline from Alberta to Texas by as much as 18 months.

The NEB said total production of Canadian crude oil would rise to 6 million barrels a day by 2035, double current levels. Though most will come from the oil sands, output from oil shale reserves like the Bakken field in Saskatchewan will also help bolster the total.

($1=$1.04 Canadian)