The Biden administration said on Friday that it would buy three million barrels of crude oil for the strategic petroleum reserve after selling 200 million barrels of oil over the course of a year.

The administration had been trying to use sales of oil from the reserve to lower oil and gasoline prices. The administration seems to have acknowledged that oil prices have fallen since this summer, when they briefly rose above $120 a barrel, and that the government no longer needs to sell oil.

The West Texas Intermediate benchmark settled at $74.29 a barrel on Friday, its lowest level of the year. The national average for regular fuel was $3.18 a gallon on Friday, which is less than it was a year ago.

Congress created the reserve in 1975 in order to protect the United States from a supply shortage caused by natural disasters, war or other issues. During the Iraq-Kuwait crisis in 1990-91, Hurricane Katrina in 2005 and the Middle East disruptions of the Arab Spring in 2011), the reserve was used.

The administration has sold 180 million barrels from the reserve since the start of the Russian war. The department said that the purchase is an opportunity to get a good deal. In October, the administration said it would begin to replenish the reserve.

The administration wants to sell high and buy low in order to encourage oil companies to keep production up. The goal of the Biden team is to prevent another energy price jump. Republicans have criticized Mr. Biden and Democrats for high inflation.