OKLAHOMA CITY — A new technique that tapped previously inaccessible supplies of natural gas in the United States is spreading to the rest of the world, raising hopes of a huge expansion in global reserves of the cleanest fossil fuel.
Italian and Norwegian oil engineers and geologists have arrived in Texas, Oklahoma and Pennsylvania to learn how to extract gas from layers of a black rock called shale. Companies are leasing huge tracts of land across Europe for exploration. And oil executives are gathering rocks and scrutinizing Asian and North African geological maps in search of other fields.
The global drilling rush is still in its early stages. But energy analysts are already predicting that shale could reduce Europe’s dependence on Russian natural gas. They said they believed that gas reserves in many countries could increase over the next two decades, comparable with the 40 percent increase in the United States in recent years.
“It’s a breakout play that is going to identify gigantic resources around the world,” said Amy Myers Jaffe, an energy expert at Rice University. “That will change the geopolitics of natural gas.”
More extensive use of natural gas could aid in reducing global warming, because gas produces fewer emissions of greenhouse gases than either oil or coal. China and India, which have growing economies that rely heavily on coal for electricity, appear to have large potential for production of shale gas. Larger gas reserves would encourage developing countries to convert more of their transportation fleets to use natural gas rather than gasoline.
Shale is a sedimentary rock rich in organic material that is found in many parts of the world. It was of little use as a source of gas until about a decade ago, when American companies developed new techniques to fracture the rock and drill horizontally.
Because so little drilling has been done in shale fields outside of the United States and Canada, gas analysts have made a wide array of estimates for how much shale gas could be tapped globally. Even the most conservative estimates are enormous, projecting at least a 20 percent increase in the world’s known reserves of natural gas.
One recent study by IHS Cambridge Energy Research Associates, a consulting group, calculated that the recoverable shale gas outside of North America could turn out to be equivalent to 211 years’ worth of natural gas consumption in the United States at the present level of demand, and maybe as much as 690 years. The low figure would represent a 50 percent increase in the world’s known gas reserves, and the high figure, a 160 percent increase.