WASHINGTON (REUTERS) - The Biden administration is considering tapping the United States Strategic Petroleum Reserve (SPR) to cool oil prices in conjunction with other big consumers such as China and Japan.

Such a move may not have a long-term impact on dampening US oil prices that hit a seven-year high above US$85 a barrel in late October, analysts said.

Releasing oil could allow the Biden administration to fend off criticism ahead of the 2022 mid-term elections that it has done little to counter rising prices.

By moving in tandem with other big consumers such as China and Japan, it could also allow US President Joe Biden to say he took action after Saudi Arabia and Russia, members of the Opec+ production group, resisted US calls to pump more oil into global markets.

Here are the issues surrounding using the SPR.

Why was the SPR created?

The US created the SPR in 1975 after the Arab oil embargo spiked gasoline prices and damaged the US economy. Presidents have tapped the stockpile to calm oil markets during war or when hurricanes hit oil infrastructure along the US Gulf of Mexico.

How much oil does the SPR hold?

The reserve currently holds about 606 million barrels in dozens of caverns in four heavily guarded locations on the Louisiana and Texas coasts. That's enough oil to meet US demand for more than a month.

The country also maintains small heating oil and gasoline reserves in the US Northeast.

What other countries have strategic reserves?

Besides the US, the other 29 member countries in the International Energy Agency (IEA), including Britain, Germany, Japan and Australia, are required to hold oil in emergency reserves equivalent to 90 days of net oil imports. Japan has one of the largest reserves after China and the US.

China, an associate member of the IEA and the world's second-leading oil consumer, created its SPR 15 years ago and held its first oil reserve auction in September. Another IEA associate member, India, the third-biggest oil importer and consumer, also maintains a reserve.

Overall, the Organisation for Economic Cooperation and Development governments held more than 1.5 billion barrels of crude as at September, according to the IEA. That is about 15 days of global demand prior to the pandemic.

Can those countries release oil all at once?

US presidents can coordinate a SPR release with drawdowns in reserves by other IEA members at the same time. A potential release involving China and India would be the first instance in which the US coordinated a release that included those two nations.

How does the SPR get oil to market?

Because of its location near big US refining or petrochemical centres, the SPR can ship as much as 4.4 million barrels per day. It can take only 13 days from a presidential decision for the first oil to enter the US market, according to the Energy Department.

Under a sale, the Energy Department usually holds an online auction in which energy companies bid on the oil. Under a swop, oil companies take crude but are required to return it, plus interest.

US presidents have authorised emergency sales from the SPR three times, most recently in 2011 during a war in Opec member Libya. Sales also took place during the Gulf War in 1991 and after Hurricane Katrina in 2005.

Oil swops have taken place more frequently, with the last exchange held in September after Hurricane Ida.