SHIFTING STRATEGY

State regulators expand their quake plan to central Oklahoma

More than 5,200 square miles of central Oklahoma now will be covered under an expanded plan to deal with the state’s rise in earthquake activity and the links to saltwater disposal wells from oil and natural gas production.

The Oklahoma Corporation Commission released its latest plan Monday that covers more than 400 disposal wells into the deep Arbuckle formation in all or parts of 11 counties. The plan follows an expanded regional plan for northwestern Oklahoma released Feb. 16. Together, those two plans cover more than 10,000 square miles and more than 640 disposal wells.

The disposal wells are used to inject deep underground large volumes of saltwater that come up with oil and natural gas. Most of the increase in volumes in recent years has gone into the Arbuckle formation.

Tim Baker, director of the commission’s Oil and Gas Conservation Division, said the central Oklahoma plan, like the northwest one, will reduce the total volume of wastewater by 40 percent below the totals from 2014.

Baker said the central Oklahoma expansion comes after several more localized actions in the past year, including restrictions in the Cushing, Crescent and Edmond areas. The volume reduction plan will be phased in over two months, with full compliance expected by May 28.

The Oklahoma Geological Survey recorded more than

900 earthquakes greater than magnitude 3.0 in 2015, up from 579 in that category in 2014.

So far this year, more than 200 earthquakes greater than magnitude 3.0 have hit Oklahoma, including seven greater than magnitude 4.0.

The central Oklahoma plan covers more than 120 operators.

Among the companies with the largest number of disposal wells are Devon Energy Corp. (54 disposal wells); American Energy Woodford LLC (22 disposal wells); Equal Energy U.S. Inc. (17); and Range Production Co. (16).

Expanded area of interest

Separately, the commission said it is expanding a previously defined “area of interest” to include more restrictions on Arbuckle disposal well operations in areas that haven’t yet seen earthquake activity.

Baker said that expansion will bring another 118 Arbuckle disposal wells under the commission’s “yellow light” earthquake risk system.

Operators will have to prove the disposal well hasn’t drilled into the basement rock and provide daily and weekly volume reporting.

Researchers have said drilling through the Arkbuckle into the crystalline basement could increase the risk of triggered earthquakes.

“The AOI (area of interest) expansion is a proactive move to get ahead of the earthquake activity,” Baker said.

Under the commission’s “traffic light” system for permitting Arbuckle disposal wells, applications cannot be administratively approved. They must go before the commission, and permits must be reviewed every six months.

Corporation Commission spokesman Matt Skinner said there are fewer than six pending, interim orders asking the three-member commission to approve Arbuckle disposal wells in “yellow light” areas.

Baker said the commission’s latest regional directives have been helped by emergency funding from Gov. Mary Fallin and grants from the Oklahoma Energy Resources Board and the Groundwater Protection Council.

“We have also begun the process of a huge upgrade in our computing power, which will give us far more powerful tools and provide more data to researchers,” Baker said.

The latest Corporation Commission actions on disposal wells come after several public forums earlier this year where residents expressed their frustrations with the earthquake response from regulators and lawmakers.