Oklahoma Agency Calls for Cuts in Wastewater Well Volumes to Stem Quakes

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The Oklahoma Corporation Commission (OCC), which regulates oil and gas production activity in the state, has come up with a volume reduction plan for oil and gas disposal wells in response to the surge in earthquakes in Oklahoma.

The OCC said its Oil and Gas Conservation Division (OGCD) is implementing what it calls the largest volume reduction plan yet in western Oklahoma. The plan covers 5,281 square miles and 245 disposal wells injecting wastewater into the Arbuckle formation, where many earthquakes have occurred.

The plan was announced on Feb. 16, just days after a 5.1 magnitude earthquake was recorded in northwest Oklahoma and was felt in seven other states. The U.S. Geological Survey said it was the third-strongest temblor ever recorded in the state.

The OCC said researchers agree that wastewater injection into the Arbuckle formation poses the largest potential risk for earthquakes in Oklahoma. Most of the wastewater comes not from hydraulic fracturing operations, but rather from producing wells. The water exists in the producing formation and comes up with the oil and natural gas.

With the new initiative, in conjunction with the 191,000 barrel a day reduction plan begun in Fairview recently, the total volume cutback for the entire area will be more than half a million barrels a day, or about 40 percent, according to OGCD director Tim Baker. A barrel is 42 gallons.

“We have taken a number of actions in the Medford, Fairview, and Cherokee areas,” Baker said in the OCC’s announcement. “However, there is agreement among researchers, including our partners at the Oklahoma Geological Survey, that the data clearly underscored the need for a larger, regional response. That is why, even as we took actions in various parts of the region in response to specific earthquake events, we were already working on a larger plan.”

Baker said while the plan is a response to the continued seismicity in the area, the action will also include areas that are not yet experiencing major earthquakes.

“The wells covered in this plan include those along the western area of the plan’s boundaries where there has not yet been major earthquake activity,” said Baker. “This plan is aimed not only at taking further action in response to past activity, but also to get out ahead of it and hopefully prevent new areas from being involved.”

The plan will be phased in over four stages and two months as recommended by researchers, who caution against sudden pressure changes. Meanwhile, staff continues to work on other areas of the state, helped greatly by recent cash infusions.

Oklahoma experienced more than more than 5,800 earthquakes in 2015, up from an annual high of 167 in the years from 1977 to 2009, according to a complaint filed on Feb. 16 by the Sierra Club in federal court in Oklahoma City.

The number of earthquakes with a magnitude 3.0 or greater has risen in Oklahoma from a few dozen in 2012 to more than 900 last year. In Oklahoma’s six most earthquake-prone counties, the volume of wastewater disposal increased more than threefold from 2012 to 2014, the Associated Press reported.

Bloomberg reported that the Sierra Club’s suit claims that the wastewater disposal activities by a Chesapeake Energy Corp. unit, Devon Energy Production Co., and New Dominion LLC are triggering tremors in Oklahoma and Kansas.

In late January, Oklahoma Gov. Mary Fallin approved the use of nearly $1.4 million in state emergency funds to be split between the OCC and the Oklahoma Geological Survey. Both agencies are researching ways to reduce the number of earthquakes linked to oil & gas activities.

The funds for earthquake research will come from an emergency account used to help the state deal with natural disasters such as tornadoes and flooding.

“The emergency funding from Governor Fallin and a new grant from the Oklahoma Energy Resources Board and the Groundwater Protection Council enable us to add badly needed equipment and staff,” Baker said. “As we continue to go forward, we will continue to focus on regional approaches as supported by the latest data.”