WASHINGTON—The energy industry’s eagerness to sell unrefined oil overseas was on display Monday at a conference that included excited discussion of the government’s two recent rulings relaxing the decades-old ban on exporting U.S. oil.

John Auers, executive vice president of the engineering firm Turner, Mason & Co., said rulings by the U.S. Commerce Department allowing two Texas companies to sell minimally processed oil overseas represent a major opening for the U.S. energy industry, and not simply a technical tweak to existing rules.

“What we have now has changed the world,” Mr. Auers said at an energy conference sponsored by the U.S. Energy Information Administration.

Oil companies that want to export ultralight oil, known as condensate, without sending it to a traditional refinery would be able to do so using equipment long common in oil fields, he said.

For now, though, it appears companies seeking to export condensate still have to apply to Commerce and provide detailed explanations of their processes to ensure they fit the two existing rulings’ parameters.

The Wall Street Journal reported last month that the U.S. Commerce Department issued confidential rulings to Enterprise Products Partners LP and Pioneer Natural Resources Inc. affirming condensate that has been minimally processed qualifies as a fuel that can be exported. Congress imposed a ban on crude exports in the 1970s, but allows companies to sell refined fuels like diesel and gasoline abroad.

Finding ways to expand the application of the two private rulings was a chief interest among attendees at the conference, who peppered the panelists with questions about how the decisions could be applied to other kinds of oil.

“How can I expand the definition?” was the first question from the audience read by the panel’s moderator, EIA official Lynn Westfall.

Jacob Dweck, a partner at the Washington, D.C., law firm Sutherland Asbill & Brennan LLP who won one of the rulings from the Commerce Department, suggested there was nothing alarming about the approval. “The ruling was issued because we asked for it—and we happened to ask first.”

The rulings have come under fire from some in Congress who say they violate the export ban and are inappropriate at a time when oil and gasoline prices remain high by historical standards even though U.S. oil output has surged by 55% in the last five years.

But Mr. Dweck said Commerce’s recent moves are good energy policy, adding, “I firmly believe the rulings were correctly decided.”

Much of the crude coming from new shale fields in the U.S. is ultralight oil, which many American refiners aren’t configured to process in large quantities. This trend has pushed down condensate prices in places like Texas, where it is often sold for as much as $20 a barrel less than other traditional crudes and less than it would fetch overseas.

Many companies that produce domestic oil want to see the entire oil export ban lifted. They argue that a glut of light sweet oil is forming at the Gulf Coast, threatening to cut short a U.S. drilling boom that has created thousands of jobs and helped slash the country’s trade deficit.

But some refiners have said that threat is overblown and that they can invest in new equipment to process the ultralight oil. Daniel Yergin, a prominent energy analyst and vice chairman of the consulting firm HIS said the export ban is dated and protectionist and that the market would function more efficiently if it were lifted.

“It is really adjusting to the new reality,” he said, “and getting a better outcome than trying to continue to live in the 1970s.”

Barclays investment bank last month estimated that as much as 800,000 barrels a day of ultralight oil could be exported from the U.S. Gulf Coast if the Commerce Department’s determination is extended to others.