The Oklahoma Corporation Commission (OCC) has ordered two disposal wells to stop operations and for another three wells to reduce their disposal volume after analyzing disposal well and seismicity data in the Cushing area, the agency said Friday.

According to the OCC, American Energy-Woodford LLC (AEW) — a private independent oil and gas company formed in 2014 by American Energy Partners LP — was ordered to shut in and plug back its Louis No. 6-3 well, and to shut in its Wilson No. 11-15 well. AEW was also ordered to reduce the volume of wastewater accepted at its Calyx No. 35-2 and Clay wells.

The OCC also ordered FHA Investments to reduce volume at its FHA No. 1-15 well.

All five wells lie within a 10-mile radius of Cushing, located in Payne County, and are classified by the OCC’s Oil and Gas Conservation Division (OGCD) as “wells of interest” because they target the Arbuckle formation.

Last March, the OGCD issued a directive to operators of 347 disposal wells targeting the Arbuckle to prove they were not injecting oil and gas waste into basement rock below it. The directive was expanded to include an additional 211 disposal wells in July. That same month, the operators of another three wells agreed to change their operations (see Shale Daily, July 29; July 20; April 2).

Additional reductions were announced in August, after a swarm of 3.1-magnitude earthquakes near Oklahoma City (see Shale Daily, Aug. 18; Aug. 4).

Scientists with the Oklahoma Geological Survey (OGS) reported in April that the state was being hit by earthquakes at a rate about 600 times greater than historic background data (see Shale Daily, April 22). Seismicity increased from an average of one-and-a-half earthquakes of 3.0 magnitude or greater to about two-and-a-half such earthquakes every day in 2014.

According to the OGS, the earthquakes are primarily occurring within the crystalline basement. The majority of the state’s approximately 900 injection wells target the Arbuckle formation, which closely overlies the crystalline basement.

Last fall, Oklahoma regulators shut in a disposal well that was thought to have been drilled too deep following a spate of seismic activity in the area (see Shale Daily, Oct. 31, 2014).