New wastewater disposal wells shut down, reduced after fault line discovery

OKLAHOMA - Seismic shakeups in Oklahoma - including the record-setting 5.8 temblor that rattled Oklahoma and states as far away as Iowa - are occurring near a newly discovered fault line, scientists revealed Monday.
In response to that discovery, officials ordered some new oil and gas wastewater disposal wells to shut down or decrease operations in parts of Pawnee, Payne, Noble and Osage counties.
"We are hoping to mitigate seismicity. We certainly do not want to see another earthquake of this magnitude occur in this area," said Charles Lord, senior hydrologist with the Oklahoma Corporation Commission.
Regulators have expanded their action area to include a larger swath of land - 1,116 square miles - in the northern part of the state as they say the threat of earthquakes has shifted east following the discovery of the new fault line.
Officials have ordered dozens of wells in the region to reduce the volumes of wastewater they're pumping back into the ground. They also said Monday that they've decided to allow some wells, which were closed immediately following the earthquake, to reopen.
"The emphasis is to protect the fault that's triggering the earthquakes," said Tim Baker, director of the regulatory commission's oil and gas division in Oklahoma. "So we've shifted our emphasis on where the new fault is. The risk is lower now to the south."
The federal Environmental Protection Agency, which regulates the wells in Osage County, has pledged its actions will mirror those taken by the state, state officials said.
In a statement, EPA spokesman Joseph Hubbard said his agency has been in touch with well operators in Osage County about the "expansion of the seismicity impact area of concern," and is working with operators in the sovereign Osage Nation.
"Additional decisions are expected as the (U.S. Geological Survey) continues to evaluate seismic activities in the area and provide information to regulatory officials," Hubbard said.
In all, 32 wells in Oklahoma now face a mandatory shutdown.
Oklahomans were jolted awake on Sept. 3 by the state's strongest recorded quake in history - a 5.8-magnitude temblor, according to the USGS - that injured one person and damaged numerous homes and businesses.
The spike in state earthquakes during the past few years has been blamed in part on the oil and gas industry's practice of pumping millions of gallons of wastewater disposal wells into the Earth's surface.
The energy industry, Lord said, has been understanding and accepting of the new regulations.
"They're kind of stunned, but they're very polite and they're very cooperative," he said. "And they realize what we're doing is an absolute necessity."
Oklahoma Geological Survey Director Jeremy Boak said locating faults in the state has posed a real challenge for scientists and regulators.
"We're just beginning to define where they all are," he said. "And some of them are showing up simply because of the locations of the earthquakes."
Boak said while he believes the number of earthquakes overall is declining, there is the continued possibility of earthquakes or equal or larger size in the region.
"I'm more concerned, I think, about whether there's another one of these faults out there that was cued up and ready to go," he said.
Janelle Stecklein covers the Oklahoma Statehouse for CNHI's newspapers and websites. Reach her at jstecklein@cnhi.com.

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