Hydraulic fracturing, known as fracking, has drawn significant opposition in the United States and France because of concerns that the fluids used can pollute groundwater. Also, the process requires vast amounts of water, a problem since many of the fields are in dry regions.

Another barrier to widespread exploitation of oil shale is that few companies have the expertise and experience to do the work. Chinese and Indian oil companies are investing in joint shale ventures in the United States and other countries in part so they can learn the new exploration and drilling techniques.

The search for oil in tight rocks began in the United States about three years ago, and the potential for oil has been found from Texas to Michigan, California to Ohio. Domestic oil production from shale has grown to more than half a million barrels a day since 2009 and could reach three million barrels a day by 2020.

Oil companies are speculating that the early successes in the United States can be duplicated around the world. Exploration for gas from shale began a couple of years ago in China and around Europe, particularly Poland, and experts say some of those fields have oil potential as well.

“It could potentially be a game changer,” said Fadel Gheit, a managing director and senior oil analyst at Oppenheimer & Company. “We are going to see much wider distribution of oil reserves, to the benefit of the whole world. It could rerank countries, in which the very needy might become self-sufficient. Countries like Canada and Australia could potentially become the new Saudi Arabia for energy.”

Argentina certainly has high hopes for shale oil from the southern Patagonian province of Neuquén. The 150 million barrels of recoverable shale oil found in the Vaca Muerta represents an increase of 8 percent in Argentina’s reserves, and the find was the biggest discovery of oil in the country since the late 1980s.