Oklahoma on right track in addressing quakes
OUR VIEWS |
AS of the middle of last week, Oklahoma had experienced 110 fewer magnitude-3.0 and greater earthquakes this year than it had during the same period of time in 2015. Why that’s so, exactly, is up for debate.
We would like to think new regulations regarding the disposal of wastewater have something to do with it.
In March, the Oklahoma Corporation Commission expanded its plan to deal with quake activity, designating more than 5,200 square miles of central Oklahoma as an area where wells must reduce their volumes of wastewater. The commission had done the same for an area of northwestern Oklahoma a month earlier.
These moves placed more than 10,000 square miles and 640plus disposal wells under heightened scrutiny by commission regulators. The hoped-for result is a 40 percent reduction in the wells’ total volume of wastewater compared with 2014.
The commission this year also expanded a previously defined “area of interest” to include more restrictions on disposal wells in parts of the Arbuckle formation that hadn’t been affected by earthquakes. Those operators are providing regular volume data to the commission to show they’re not disposing wastewater too deep into the formation, something researchers have said could help trigger quakes.
These moves came about the time a report by the U.S. Geological Survey linked wastewater disposal to seismic activity. The agency found that Oklahoma, Kansas, Texas, Arkansas, New Mexico and Colorado faced the potential for earthquake activity.
The USGS said last week there had been 448 magnitude-3.0 or greater quakes in Oklahoma to date, compared with 558 through early August of last year. In total, our state saw more than 900 quakes of this magnitude in 2015, a significant increase over the 579 in 2014.
It’s certainly true that there haven’t been as many wells drilled this year as in years past, due to a particularly challenging stretch for the oil and gas industry. The fewer wells drilled, the less wastewater there is disposed, and thus the less likely it is for industry-related quakes to occur. (There also have been quakes in areas of the state where drilling is not considered to be a contributing factor.)
Jefferson Chang, a geophysicist with the Oklahoma Geological Survey, told USA Today last week that monitoring quakes in the state is a challenge, and no study has conclusively surveyed Oklahoma. Thus, “It’s really hard to quantify what is episodic and what is ‘normal,’ ” Chang said.
In the meantime, regulators and energy companies continue to collaborate on the best way forward. An example is research on inactive Arbuckle formation disposal wells in Alfalfa, Grant, Payne and Logan counties. “By measuring Arbuckle pressure changes in the inactive disposal wells, researchers are hoping to collect data to enhance Oklahoma’s regulatory response to the rise in earthquakes,” The Oklahoman’s Paul Monies reported.
The Oklahoma Geological Survey is leading this effort, which includes the Corporation Commission and the Oklahoma Independent Petroleum Association. Kim Hatfield, head of the OIPA’s induced seismicity working group, told Monies that unlocking some of the mysteries about the Arbuckle formation is key.
“Understanding how it works is the first step in us being able to figure out how we can change practices and make sure we’re not likely to trigger seismicity,” he said.
Continued close oversight, measured responses and collaboration are the right recipe for addressing this ongoing concern.