The swarm of earthquakes over the past few years could have implications on the state's oil and natural gas industry.
The Oklahoma Corporation Commission is working with the Oklahoma Geological Survey, oil companies and water disposal well operators to develop best practices, which could eventually become new rules.
“It's been an ongoing effort to collect data,” Corporation Commissioner Dana Murphy said. “A lot of this has to do with risk management. The geology in Oklahoma is very complex. The areas we are concerned about have active faults. Ninety percent of the faults in Oklahoma are not active. We need to know where to focus.”
A geologist herself, Murphy regularly considers rocks and faults before approving new disposal well permits.
“With every order that comes up for a disposal well, I ask questions for myself. I have concerns about it,” she said.
But that process is far from certain.
“It's very difficult. Faults are very interpretive,” she said. “You can provide the same seismic data to different geologists, and they will interpret it differently.
“It's a challenge to know where the faults are and if the faults are active.”
While it is still unclear exactly what is causing the earthquakes, part of the investigation has centered whether certain water injection wells could be contributing.
On average, wells in Oklahoma produce about 10 barrels of saltwater for every barrel of oil they release, said Brad Woodard, vice president of regulatory affairs for the Oklahoma Independent Petroleum Association. And some of the state's rock formations — including northern Oklahoma's Mississippian formation — produce up to twice that volume of water.
The water usually is returned deep underground through disposal wells designed to handle high pressure and large volumes of water.
Oklahoma is dotted with more than 4,500 private and commercial water disposal wells. More than 6,600 enhanced recovery wells throughout the state are used to pump water into a producing rock layer in an effort to push oil through a rock formation.
Injection and disposal wells have been used throughout Oklahoma for much of the state's history.
Woodard said the oil producers are working with the Oklahoma Geological Survey and the Oklahoma Corporation Commission, but that more research is still needed.
“We have to let science and research prevail. We do not support any initial knee-jerk reactions,” he said. “We want to be as prudent and practical as we can to assist data capture and to be a partner with the agencies to support understanding.
While the wells have not been linked conclusively to the earthquakes, Oklahoma Geological Survey seismologist Austin Holland said it is wise to look at whether Oklahoma's injection well practices should be updated.
“The concept of best practices does not require us to understand whether a specific earthquake may have been caused by an incident or not,” he said. “We are working on a set of best practices that is independent and based on scientific evaluation.”