In its latest act to address concerns about induced earthquakes, the Oklahoma Corporation Commission has directed operators of an additional 211 wastewater injection wells to reduce their depths.
The Corporation Commission in a Friday news release said a $200,000 grant from the Oklahoma Secretary of Energy and Environment will help the agency take the action. A similar directive in March applied to more than 300 disposal wells that injected into the state’s deepest formation, the Arbuckle.
The latest directive expands the coverage area to include 21 of Oklahoma’s 77 counties. Well operators will have until Aug. 14 to prove they aren’t injecting below the Arbuckle.
Tim Baker, director of the commission’s Oil and Gas Conservation Division, said the primary focus remains on high-volume wells injecting into the Arbuckle; research shows those wells hold the highest potential for induced seismicity.
“Also, we have had recent seismicity in some areas that don’t have any of the high-volume, deep disposal wells considered of highest potential risk, most notably in the northern Oklahoma County and southern Logan County area,” Baker said in a statement. “Operators of low-volume Arbuckle disposal wells in the area that have long been proven to be operating at the proper depth have now voluntarily shut down their wells to aid research efforts.”
The March directive established seismic areas of interest that applied to a 16-county area and 347 of approximately 900 Arbuckle disposal wells in Oklahoma. Mounting scientific research has pointed to wastewater coming out of the Arbuckle and contacting the state’s crystalline “basement” as a trigger for quakes. The U.S. Geological Survey has said the crystalline rock has faults and is critically stressed.
Baker noted the latest directive isn’t a final step and that more actions are being formulated.
Michael Teague, Oklahoma secretary of energy and environment, said expanding the area of interest is the correct action to take at this point.
“Though it’s too soon to know the results of the first directive, seismologists agree that injection into or in communication with the basement poses a high risk for seismicity, so this expansion makes sense,” Teague said in a statement.
Gov. Mary Fallin also released a statement applauding the expanded regulations. She said the Corporation Commission is taking “active and appropriate steps” to address seismic activity.
“The state will continue to work with all parties to pursue sound, scientifically driven policy to reduce earthquakes in Oklahoma and protect homeowners,” Fallin said.