Stop the shaking
An earthquake early Thursday prompted Oklahoma regulators to direct a salt water disposal well operator to shut down.
I want to see the earthquake rate from Enid, northwest, decline more. It has declined a lot, but this whole business of not being out of the woods yet comes down to areas where you are most worried about.” Jeremy Boak
Director of the Oklahoma Geological Survey
HENNESSEY — The Oklahoma Corporation Commission directed the operator of a saltwater disposal well south of Hennessey on Thursday to discontinue that well’s operations after a 3.2 magnitude earthquake struck nearby early the same day.
Thursday’s earthquake was one in a string of eight temblors that have occurred within a 1-square-mile area of Kingfisher County in 2018.
All of the earthquakes except for Thursday’s happened in February, ranging in magnitudes from 3 to 3.7.
The earthquakes have been centered in an area about 4 miles south of town. The saltwater disposal well affected by Thursday’s order, the Choate SWD #1 operated by Choate Disposal Services, was closest to where the activity had occurred.
The commission, acting with Oklahoma’s Coordinating Council on Seismic Activity, also on Thursday directed operators of 15 other saltwater disposal wells near Enid to reduce or limit ongoing injection activities at those wells.
That action aims to further moderate earthquake issues in that part of the state.
Residents in that area experienced two magnitude 4 temblors in March, bringing the statewide total of earthquakes that strong to four in 2018. There were six that strength or greater in 2017.
Operators of the Enid area disposal wells where the commission directed reductions of daily injection rates as part of Thursday’s action are SK Plymouth LLC and SandRidge Exploration and Production LLC.
The action involving
the other eight disposal wells within the Enid area directed those operators to limit daily injection rates to their averages during the previous 60 days.
Officials said none of the eight have average injection rates of more than 2,000 barrels per day, and operators of those wells weren’t named as part of the directive.
All 15 of those wells, however, operate within 10 miles of the March earthquakes, and the latest restrictions also follow others taken in 2016 that reduced daily injection rates at those wells by 40 percent, officials said.
Jeremy Boak, director of the Oklahoma Geological Survey, said the latest direction to operators attempts to prompt further reductions in seismic activities near both Enid and Hennessey.
“I want to see the
earthquake rate from Enid, northwest, decline more,” Boak said. “It has declined a lot, but this whole business of not being out of the woods yet comes down to areas where you are most worried about.”
Regarding the activity near Hennessey, Boak said that cluster of earthquakes does a great job of telling researchers where the area’s previously undetected fault is located.
“You just usually don’t see them lined up quite so nicely,” he said.
As for the Choate SWD #1, officials said its operator already had been required to reduce its daily injection rate in October as part of a directive issued involving it and the operator of another, nearby injection well.
The operator of the second well closed down that operation in December, they said.