Oklahoma expands earthquake prevention plan

OREANDA-NEWS. September 13, 2016. Oklahoma regulators expanded restrictions on oil and gas wastewater disposal wells to include an area of more than 1,100 square miles, part of an effort to prevent further earthquakes after a 5.6 magnitude quake near Pawnee, Oklahoma, on 3 September.

The restrictions will apply to 67 wells that flow into the Arbuckle formation. Of those, 32 will be shut for at least six months.

The Oklahoma Corporation Commission said the expansion followed new data on faults in the region and that it was notifying operators about the wider area of restrictions today.

The commission said the 3 September earthquake amounted to "an emergency situation having potentially critical environmental or public safely impact resulting from the operation of saltwater disposal wells."

Shortly after the 3 September earthquake, the commission announced restrictions on 37 wells in a 725-square-mile "area of interest." In addition, the US Environmental Protection Agency directed oil and gas producers in Osage county, Oklahoma, to shut 17 wastewater disposal wells on land under federal jurisdiction.

The Oklahoma Oil and Gas Association said earlier this month that the immediate impact of the emergency regulations is severe for producers who have to shut the wells and that there is concern that the restrictions could become permanent.

But the group also said that the industry can accept any outcome as long as the decision is based on good data and good science.

The increase in earthquakes in Oklahoma has coincided with a surge in oil and gas drilling activity. The number of earthquakes in Oklahoma above a magnitude 3.0 increased to more than 900 in 2015, compared to about 580 in 2014 and about 100 in 2013, according to the US Geological Survey.

The Oklahoma Corporation Commission has been taking steps to reduce wastewater injection wells to prevent further seismic activity. A large program announced in May included limits on more than 600 wastewater disposal wells in the Arbuckle formation. That program was further expanded last month after earthquakes near Luther, Oklahoma.

The Oklahoma Corporation Commission could not estimate how much output has been curtailed by earthquake-prevention regulations.