LOMA LA LATA, Argentina – In a desertlike stretch of scrub grass and red buttes, oil companies are punching holes in the ground in search of what might be one of the biggest recent discoveries in the Americas: enough gas and oil to make a country known for beef and the tango an important energy player.

The environment is challenging, with resources trapped deep in shale rock. But technological breakthroughs coupled with a feverish quest for the next major find are unlocking the door to oil and natural gas riches here and in several other countries in the Americas not traditionally known as energy producers.

That is quickly changing the dynamics of energy geopolitics in a way that had been unforeseen just a few years ago.

From Canada to Colombia to Brazil, oil and gas production in the Western Hemisphere is booming, with the United States emerging less dependent on supplies from an unstable Middle East.

Central to the new energy equation is the United States itself, which has ramped up production and is now churning out 1.7 million more barrels of oil and other liquid fuel per day than in 2005.

“There are new players and drivers in the world,” said Ruben Etcheverry, chief executive of Gas and Oil of Neuquen, a state-owned energy firm that is positioning itself to develop oil and gas fields here in Patagonia. “There is a new geopolitical shift, and those countries that never provided oil and gas can now do so. For the United States, there is a glimmer of the possibility of self-sufficiency.”

Oil produced in Persian Gulf countries — most notably Saudi Arabia, Iran, the United Arab Emirates, Kuwait and Iraq — will remain vital to the world’s energy picture and to U.S. needs. But what was once a seemingly unalterable truth — that American oil production would steadily fall while the United States remained heavily reliant on Middle Eastern supplies — is being turned on its head.

Since 2006, exports to the United States have fallen from all but one major member of the Organization of the Petroleum Exporting Countries, the net decline adding up to nearly 1.8 million barrels per day. Canada, Brazil and Colombia have increased exports to the United States by 700,000 barrels daily in that time span and now provide nearly 3.4 million barrels a day.

Six Persian Gulf suppliers provide just 22 percent of all U.S. imports, the nonpartisan U.S. Energy Information Administration said this month. America’s neighbors in the Western Hemisphere, meanwhile, provide more than half — a figure that has held steady for years because, as production has fallen in the oil powers of Venezuela and Mexico, it has gone up elsewhere.

Production has risen strikingly fast in places as divergent as the tar sands of Alberta, Canada, and the “tight” rock formations of North Dakota and Texas – basins with resources so hard to refine or reach that they were not considered economically viable until recently. Oil is gushing in once-dangerous regions of Colombia and far off the coast of Brazil, under thick salt beds thousands of feet below the surface.

A host of new discoveries or rosy prospects for large deposits also has energy companies drilling in the Chukchi Sea inside the Arctic Circle, deep in the Amazon, along a potentially huge field off South America’s northeast shoulder, and in the roiling waters around the Falkland Islands.

“A range of big possibilities for oil are opening up,” said Juan Carlos Montiel, as he directed a team from the Argentine-controlled company YPF to drill while a whipping wind brought an autumn chill to the potentially lucrative fields here outside A?. “With the exploration that is being carried out, I think we will really increase the production of gas and oil.”

Because oil is a widely traded commodity, oil market analysts say, the upsurge in production in the Americas does not mean the United States will be immune to price shocks. If Iran were to close off the Strait of Hormuz, stopping tanker traffic from Middle East suppliers, a price shock wave would be felt worldwide.

But the new dynamics for the United States — an increasingly intertwined energy relationship with dependable ally Canada and more reliance on democratic Brazil — mean U.S. energy supplies are more assured than before, even if oil from an important Persian Gulf supplier is temporarily halted.

Perhaps the biggest development in the worldwide realignment is how the United States went from importing 60 percent of its liquid fuels in 2005 to 45 percent last year. The economic downturn in the United States, improvements in automobile efficiency and an increasing reliance on biofuels all played a role.

But a major driver has been the use of hydraulic fracturing. By blasting water, chemicals and tiny artificial beads at high pressure into tight rock formations to make them porous, oil production rose in North Dakota from a few thousand barrels each day a decade ago to nearly half a million barrels today.

Conservative estimates are that oil and natural gas produced through “fracking,” as the process is better known, could amount to 3 million barrels a day by 2020.

“We have a revolution here,” said Larry Goldstein, director of the Energy Policy Research Foundation in New York.

“In 47 years in this business, I’ve never seen anything like this. This is the equivalent of a Category 5 hurricane.”

All of this has happened as exports from Mexico and Venezuela have fallen in recent years, a trend analysts attribute to mismanagement and lack of investment at the state-owned oil industries in those countries.

Even so, there is a possibility that new governments in Mexico and Venezuela — Mexico elects a new president July 1 and Venezuelan President Hugo Chavez is stricken with cancer — could open up the energy industry to the private investment and expertise needed to increase production, analysts say.

“There’s a lot of upside potential in Latin America that will boost the oil supply over the medium term,” said RoseAnne Franco, who analyzes exploration and production prospects in the region for the energy consultant Wood Mackenzie. “So it’s very positive.”

Much of the exploration, though, will not be easy, cheap or, as in the case of Argentina, free of political pitfalls.

Price controls on natural gas and import restrictions have made doing business in Argentina hard for energy companies. And last month, President Cristina Fernandez de Kirchner’s populist government stunned oil markets by expropriating YPF, the biggest energy company here, from Spain’s Repsol.

But the prize for energy companies is potentially huge. Repsol estimated this year that a cross-section of the vast Dead Cow formation here in Neuquen province could hold nearly 23 billion barrels of gas and oil. That followed a U.S. Energy Information Administration report that said Argentina possibly has the third-largest shale gas resources after China and the United States.

“All the top-of-the-line companies are here,” said Guillermo Coco, the energy minister in Neuquen province, reeling off the names of giants including ExxonMobil, Chevron and Royal Dutch Shell.

Although only about 200 wells have been drilled, Coco said energy companies here talk of drilling 10,000 or more in the next 15 years.