WASHINGTON, June 4 (Reuters) - The U.S. could hasten the rate of replenishing the Strategic Petroleum Reserve as maintenance on the stockpile is completed by the end of the year, Energy Secretary Jennifer Granholm told Reuters on Tuesday.

Granholm said she believes the global oil market is well-supplied and that she does not expect a big increase in oil and gas prices in the "next short while."

The Energy Department this year has been buying about 3 million barrels of oil per month for the Strategic Petroleum Reserve after selling 180 million barrels in 2022 following Russia's invasion of Ukraine.

President Joe Biden, a Democrat, directed the sale, the largest ever from the SPR, in an effort to control gasoline prices after the invasion. But the move sank levels in the reserve to the lowest in 40 years, leading to criticism from Republicans that it left the U.S. emergency oil buffer too thin.

"It could pick up more than that," Granholm told Reuters in an interview in Washington, about the 3 million barrel per month pace. She said that a couple of the SPR's four sites on the coasts of Texas and Louisiana have been in maintenance.

"All four sites will be back up by the end of the year, so one could imagine that pace would pick up, depending on the market," she said.

The U.S. has bought back about 38.6 million barrels and canceled congressionally mandated sales of 140 million barrels through 2027. The administration has said it wants to keep buying oil as long as the price remains below $80 a barrel .

"We want to continue to take advantage of the market when it is right for the taxpayers," Granholm said.

The Organization of Petroleum Exporting Countries agreed on Sunday to extend production cuts into 2025 amid tepid demand growth. But Granholm was not concerned the agreement could result in higher oil prices. "It seems that they have backed off a bit from their goals of getting" much higher oil prices she said about OPEC. "And so that is encouraging."

LNG PAUSE

The Biden administration intends to finalize an environmental and economic review of its liquefied natural gas exports by the end of the first quarter of 2025, following a period of public comment, Granholm said.

She did not expect the pause to have any impact on U.S. competitiveness in the global LNG market, given U.S. exporters are only shipping a fraction of what has already been authorized.

The oil industry, Republican lawmakers, and presidential candidate Donald Trump have lambasted the Biden administration for its decision earlier this year to pause LNG export permitting.

“It doesn’t pause anything that’s already happening and already authorized,” Granholm said.

The U.S. is the world’s top LNG exporter at around 14 billion cubic feet per day. Granholm said the administration had authorized 48 billion cubic feet per day of LNG exports.

OIL COMPANY CONSOLIDATION

Granholm said she was worried about the recent flurry of mergers and acquisitions in the U.S. oil industry involving companies like Exxon Chevron and ConocoPhillips saying they risked harming consumers.

“I’m always worried about consolidation in any industry and what the impacts for real people are on that, and the antitrust issues related. We've got to be vigorous on that throughout. Competition is good. And so consolidation is anti-competition, often. And I think that we should all be concerned about that.”

Asked if she supported efforts by Democratic lawmakers to convince Attorney General Merrick Garland to launch an investigation into the oil industry, Granholm said: "I think it's up to Merrick Garland whether he takes this up. As a Cabinet member I respect his decision."

As the U.S. and allies look to reduce dependence on fossil fuels and boost output of electric vehicles and renewable power, Granholm said the creation of a "strategic resilience reserve" to stockpile critical minerals like graphite and lithium is a "good idea." The reserve could protect against dependence on China for such minerals. The administration is talking with allies and should have announcements on critical minerals soon, Granholm said. (Reporting by Timothy Gardner and Richard Valdmanis; Editing by David Gregorio)