Following two decades of depressed global searching for oil and gas, frontier exploration is bouncing back. The industry’s biggest producers had cut spending on costly global efforts as they leaned into West Texas’ Permian Basin and the rest of the onshore U.S., as well as proven offshore basins, including the Gulf of Mexico.

For context, that decision proved to be wise: The shale boom—with its horizontal drilling coupled with hydraulic fracturing, or fracking—turned the U.S. from a country that pumped out 5 million barrels of oil a day 20 years ago into a world-leading powerhouse churning out almost 14 million barrels daily and even exporting nearly 5 million barrels.

That allowed Chevron, Exxon Mobil, and others to ease off of the metaphorical gas pedal globally and instead focus much more on literal oil and natural gas drilling domestically. With U.S. shale now potentially peaking and plateauing—or even entering a modest decline—the pendulum is swinging back again.

Global exploration is recovering from historically low levels, so progress remains gradual, but it is clearly rebounding, said Patrick Rutty, director of global intelligence at Enverus.

“Given recent drilling success and diminished concerns over peak [oil] demand, the industry is reprioritizing exploration, a dynamic that should drive resource capture to relatively high levels over the next five years,” Rutty said. He added that there remains a risk of a global oil shortfall later this decade as demand continues to rise in the short term.

Another reason why global exploration had stalled is the ongoing projection that global oil demand would eventually peak and began to decline later this century as the world moves to electric vehicles and other cleaner fuel sources. But, while demand growth has slowed, it is still on the rise, and a shortfall now looks like the greater short-term risk.

That is especially true because U.S. shale wells tend to dry up more quickly than conventional wells after producing large oil volumes for a few years.

Return to the frontiers

So Big Oil is now taking action.

One notable sign: Previously war-torn Libya is awarding exploration licenses to international companies for the first time in nearly 20 years. In addition to Chevron, Italy’s Eni, Spain’s Repsol, and others won new licenses.

Chevron is returning to Libya after previously exiting the country in 2010, during a time of intense political unrest.

“Libya has significant proven oil reserves and a long history of producing its resources,” said Chevron vice president of exploration Kevin McLachlan. “Chevron is confident that its proven track record in developing oil and gas projects and its technical expertise gives it the ability to support Libya to further develop its resources.”

Chevron said the deal showcases the company’s growing focus on the Eastern Mediterranean region in Northern Africa and the Middle East. Chevron is also in the process of expanding its operations in Egypt, Cyprus, and Turkey.

On its Feb. 10 earnings call, BP called its drilling effort offshore of Libya the “most watched exploration well in the industry right now.”

Chevron also is negotiating a potential return to Iraq. In October, Exxon Mobil signed an agreement to return to Iraq as well.

Chevron chairman and CEO Michael Wirth highlighted the global exploration momentum on his Jan. 30 earnings call. He said there’s a broader uptick in interest from countries that want American companies to invest in their resource extraction.

“It’s been a decade or more since we’ve last really had any kind of a serious look at Libya. Those things are changing,” Wirth said. “The resource potential in some of these countries is undeniable. Iraq and Libya are two of the largest resource holders in the world.”

Chevron’s top oil production hub is, by far, the United States—accounting for close to half of its total volumes. Next up is its leadership in Kazakhstan.

After having acquired Hess last year for $53 billion, Chevron also is a leader in the emerging oil power of offshore Guyana. The company is taking part in a new, forced partnership with rival Exxon, which first made the Guyana discovery a decade ago—arguably the largest oil find this century. But such big discoveries are increasingly rare in a mature industry.

The question is whether that will change now that exploration is picking up again in South America, Africa, and other so-called frontier regions. In South America, international investments are rising in Brazil, Argentina, Guyana’s neighbor Suriname—and now, potentially, Guyana’s other neighbor, Venezuela, now that the Trump administration is exerting control over its oil industry.

Exxon chairman and CEO Darren Woods touted its efforts during an October earnings call.

“With the [U.S. shale] depletion curve, the industry has to continue to think long term, invest, and find resources. That, I think, you’re now seeing play out,” Woods said. “People see that resource and the horizon of it, and are shifting to the long-term, longer-cycle projects out there. We’ve never taken our eye off that.”