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The U.S. Geological Survey has released a new assessment pointing to significant undiscovered oil and natural gas resources deep beneath the Permian Basin, reinforcing the region’s long-standing role as one of the nation’s most prolific energy provinces.
According to the assessment, the Woodford and Barnett shales contain an estimated 28.3 trillion cubic feet of technically recoverable natural gas — enough to supply the United States for roughly 10 months at current consumption rates — along with 1.6 billion barrels of oil, equivalent to about 10 weeks of national demand. These resources remain undiscovered but are considered technically recoverable using existing drilling and completion technologies.
“The U.S. economy and our way of life depend on energy, and USGS oil and gas assessments point to resources that industry hasn’t discovered yet,” said Ned Mamula, director of the USGS. “In this case, we have assessed there are significant undiscovered resources in the Woodford and Barnett shales in the Permian Basin.”
While the Woodford and Barnett formations have been producing hydrocarbons since the late 1990s, cumulative output to date underscores how much remains untapped. Since production began, the two shales have yielded approximately 26 million barrels of oil, roughly equal to a single day of U.S. consumption. That disparity reflects both the technical challenges of the formations and the pace of technological advancement now reshaping unconventional energy development.
The organic-rich Woodford and Barnett shales lie as deep as 20,000 feet below the surface, significantly deeper than many of the Permian Basin’s more heavily developed zones. Advances in horizontal drilling and hydraulic fracturing have made it possible to target these formations, opening access to resources that were previously considered too deep or complex to pursue economically.
The assessment builds on a half-century of USGS energy analysis. The agency began formally assessing domestic petroleum resources following the Arab oil embargo of the 1970s, which exposed vulnerabilities in U.S. energy supply and prompted a federal mandate to better understand undiscovered resources. Since then — particularly after the shale boom of the early 2000s — the United States has emerged as a global energy powerhouse.
Still, unlocking these deeper reserves will not be easy. Toti Larson, principal investigator at the University of Texas Bureau of Economic Geology’s Mudrock Systems Research Laboratory, told the Houston Chronicle that renewed interest in the Woodford and Barnett reflects companies pushing beyond traditional drilling targets.
“When you hear that there’s increased activity in Woodford, Barnett, what that’s telling you is that they’re looking beyond the sort of traditional landing zones,” Larson said.
The formations present new challenges: greater depth, higher temperatures, increased associated gas, and — in the Barnett — higher clay content that complicates drilling. Identifying productive “sweet spots” across the vast Permian Basin remains a key exploration hurdle.
“The potential is massive,” Larson said. “But the complexity is really trying to determine where the Woodford is most likely to produce oil. That’s what still makes it an exploration target.”