One of the most productive regions in the petroleum world for almost a century, the Permian Basin is far from tapped out, according to a new U.S. Geological Survey (USGS) assessment.
The report, released in November, estimates that the Wolfcamp portion of the eastern Midland sub-basin contains 20 billion barrels of oil trapped in West Texas shale layers, the largest such assessment ever made in the United States.
By some estimates, the oil is worth some $900 billion at today’s prices, although the assessment did not attempt to determine whether producing the resources would be profitable.
“It’s the first time we ever looked at it ... that was a first,” said Stephanie Gaswirth, research geologist at the Central Energy Resources Science Center.
Gaswirth said she is already working on the next step: an assessment of the Delaware basin portion of the Permian, which lies in West Texas and New Mexico.
“If there are any operators who want to talk to me about the geology, we always welcome input from industry if they are willing to come in and chat with us,” she said.
She expects that assessment to be completed sometime in 2018.
“It’s a very productive area. It’s not just oil, but oil and gas,” she said.
As with the Wolfcamp project, “We go in and gather as much geologic information as possible. We rely on what’s out there – literature, maps, drilling and production information databases.”
“The (Wolfcamp) number means 20 billion barrels of undiscovered, technically recoverable oil using today’s technology,” she said.
The Wolfcamp shale also holds an estimated 16 trillion cubic feet of associated natural gas and 1.6 billion barrels of natural gas liquids, according to the assessment.
The continuous oil estimate is almost three times larger than the agency’s 2013 Bakken-Three Forks resource assessment.
“The fact that this is the largest assessment of continuous oil we have ever done just goes to show that, even in areas that have produced billions of barrels of oil, there is still the potential to find billions more,” said Walter Guidroz, program coordinator for the USGS Energy Resources Program. “Changes in technology and industry practices can have significant effects on what resources are technically recoverable, and that’s why we continue to perform resource assessments throughout the United States and the world.”
Asked if the Wolfcamp findings were expected or surprising, Gaswirth said, “We (USGS) don’t go in with any expectations. We were unbiased from a geologic standpoint. We have nothing at stake here.”
New Tech, New Perspective
The Wolfcamp assessment was the first time the agency took a look at the Permian’s unconventional resources.
“The last time was in 2007 and looked mostly at conventional resources,” Gaswirth said.
Unconventional resources like those of the Wolfcamp are less well-defined, regional accumulations where the source rock is also the reservoir rock or in close proximity, she said.
It requires new technology like horizontal drilling and hydraulic fracturing, she said.
The methodology used for the assessment was standardized, as reviewed by the AAPG Committee on Resource Evaluation, she said.
“The Wolfcamp is source rock generating its own resource. It’s a shale with high organic content. It’s really thick compared to the Bakken — thousands of feet thick,” she said.
Since the 1980s, the Wolfcamp shale has been part of the Wolfberry play that encompasses Mississippian, Pennsylvanian and Lower Permian reservoirs. Oil has been produced using traditional vertical well technology, the USGS announcement said.
However, more recently, oil and gas companies have been using horizontal drilling and hydraulic fracturing, and more than 3,000 horizontal wells have been drilled and completed in the Midland Basin Wolfcamp section, the agency said.
More to Come
The Wolfcamp shale assessment was undertaken as part of a nationwide project assessing domestic petroleum basins using standardized methodology and protocol, as mandated by Congress, Gaswirth said.
Gaswirth reiterated her “no expectations” approach in regard to the forthcoming Delaware basin assessment.
“We don’t go in and say one region is better. We define the outer boundary then it’s up to the industry where they put their wells,” she said.
The Wolfcamp shale assessment is available online at usgs.gov.