The federal government has stashed away nearly 700 million barrels of oil to shield Americans from a shock that would send gasoline prices spiking.

The country dipped into the US strategic oil reserve, during several recent disruptions such as the 2011 turmoil in Libya and Hurricane Katrina in 2005.

Now, President Trump wants to sell off half of the oil sitting in the strategic reserve, which is made up of a complex of tanks and deep underground storage caverns.

Except for the fact that the sale would be done over time, little is known about the exact timing of the move. But Trump's fiscal 2018 budget estimates the it would generate roughly $16.6 billion over the next decade.

It's true that the US shale oil boom has dramatically altered the global energy landscape, turning America into a leading producer and reducing dependence on imports. The surge of American oil has also created a huge glut that OPEC is still struggling to mop up.

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All of this is a huge change from the early 1970s when the Arab Oil Embargo sparked long gas lines and hurt the American economy so much that it inspired the creation of the strategic petroleum reserve, which today is the largest stockpile of government-owned emergency oil on the planet.

Yet some energy analysts warn that selling half the SPR could backfire, especially in today's uncertain world.

"It's a bit concerning. You're reducing the government's budget deficit, but you're putting more risk onto the consumer. That's who is going to pay for it," said Carl Evans, senior crude oil analyst at Genscape, an energy market research firm.

"It does seem like a short-term cash grab," he said.

Evans pointed to the risk posed by the political strife in Venezuela and Nigeria that has caused production to tumble in those OPEC nations.

To justify the proposed sale, the Trump administration pointed to the surge in US oil output.

The national security "risk goes down dramatically when we have increased production like today," Mick Mulvaney, the director of Trump's Office of Management and Budget, told reporters on Tuesday.

But Jason Bordoff, director of Columbia University's Center on Global Energy Policy, warned that even though US oil imports are down "prices at the pump will spike" if there's a supply disruption.

"The national security asset of the SPR helps provide a cushion. It would be foolish to sell it off because of a domestic oil production boom, the longevity of which remains somewhat uncertain," said Bordoff, who served as an energy adviser to President Obama and has testified before Congress on energy policy issues.

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It's not clear if Trump wants to sell 50% of the strategic reserve from current levels, or on top of the reductions Congress recently agreed to. Those cuts would already wipe out more than 150 million barrels from the SPR, according to S&P Global Platts.

Other analysts think now is the perfect time to unload some of the strategic oil reserve, especially because there are costs linked to maintaining this complex that is located in Texas and Louisiana.

"It makes a lot of sense for the US to reduce these rather massive holdings," said Michael Dei-Michei, head of research at JBC Energy.

Selling the oil could generate a nice profit at today's prices of around $50 a barrel. The average price paid for oil in the reserve is just $29.70 a barrel.

The 688 million barrels currently sitting in the reserve are enough to cover 149 days worth of America's import needs, according to the Energy Department.

That means the US is well above the 90-day minimum required by the International Energy Agency (IEA). However, cutting half of the strategic reserve would obviously lower that cushion, potentially to below the IEA threshold. The Energy Department website notes that in the past the US has met this commitment by combining SPR stockpiles with private-sector inventories.

Bordoff, the Columbia professor, acknowledged that the dramatic changes in the world since the 1970s mean it would be wise to take time to think about the purpose and size of the SPR going forward.

"But to propose in the budget to slash it in half seems premature given that I don't know the full analysis has been done," he said.

--CNNMoney's Heather Long contributed to this report