Disposal well operations reduced following earthquakes

The Oklahoma Corporation Commission’s Oil and Gas Conservation Division order affects disposal wells within 10 miles of a 4.0-magnitude earthquake, which occurred just before 4 a.m. Thursday near Carney, followed by a series of nearby smaller quakes.

The 23 disposal wells inject wastewater into the Arbuckle formation, the state’s deepest rock formation.

Arbuckle disposal wells within 6 miles of the earthquake were ordered to shut down indefinitely, according to a Corporation Commission news release.

Disposal wells operating in the Arbuckle formation that are 6 to 10 miles from the earthquake site will have their injection volumes limited.

Those with an average injection of 500 barrels a day or less in the latest 30-day period must not exceed that average.

Larger-volume wells, those with average volumes over 500 barrels a day, must reduce volume by 50 percent.

The volume reductions and shut-ins will be phased-in over a four-week period in order to avoid a sudden change of pressure, which theoretically could increase the risk of another seismic event, according to the Corporation Commission.

Reducing the volume of oil and gas wastewater into the Arbuckle formation has been credited by the scientific community with being a key element of the more than 90% reduction in earthquakes with a magnitude of 3.0-magnitude or greater since 2015, according to the Corporation Commission.

Before Thursday, the last Oklahoma earthquake greater than 3.5-magnitude occurred on Jan. 31, 2022, when a 4.5 magnitude quake was recorded north of Enid, near the Kansas border.

Four earthquakes with a magnitude of at least 4.0 have been recorded in Oklahoma since Jan. 1, 2020. There were six 4.0-plus quakes in 2018, five in 2017, 14 in 2016 and 27 in 2015.