Oklahoma expands earthquake prevention plan

OREANDA-NEWS. August 22, 2016. Oklahoma regulators are limiting more wastewater disposal volumes from oil and gas operations, including shutting down two wells in an effort to prevent further earthquakes near Luther, Oklahoma.

The plan is a response to seismic activity in recent days in the central part of the state, said the Oklahoma Corporation Commission. which regulates the industry. In the past week, four earthquakes above a magnitude 2.5 were recorded by the US Geological Survey (USGS) in the area near the cities of Luther and Wellston. The largest was a magnitude 4.0 on 17 August, according to the USGS.

Two disposal wells within three miles of the recent activity will be shut by 25 August. In addition, 19 Arbuckle disposal wells within 10 miles of the latest earthquakes will be further limited in volume. The commission is also requiring operators to install gauges and flow meters on the wells and to record daily volumes and send weekly reports to the state.

The efforts are an expansion of a program implemented in May which included limits on more than 600 wastewater disposal wells in the Arbuckle formation.

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.

Earthquakes near Cushing, Oklahoma, have been of special concern because it is a major crude storage hub, with about 64.5mn bl of oil stored there currently, according to the US Energy Information Administration.

The broader earthquake prevention plan includes part or all of the counties of Oklahoma, Logan, Kingfisher, Garfield, Noble, Pawnee, Payne, Lincoln, Creek, Pottawatomie, and Cleveland. The state has taken action to reduce wastewater injection volumes by 1mn b/d since March 2015.

Separately, Oklahoma regulators said last month that they are investigating oil and gas operations near Blanchard, Oklahoma, searching for any ties to a recent uptick in earthquake activity there. There are no deep Arbuckle disposal wells within at least 20 miles of the earthquakes near Blanchard.

The Oklahoma Corporation Commission does not have an estimate on how much oil and gas output has been curtailed because of the earthquake-prevention regulations.