More oil/natural gas wastewater disposal wells have joined the Oklahoma Corporation Commission’s (OCC) action plan for reduced injections following a spate of minor earthquakes around Cushing, OK.

The OCC’s Oil and Gas Conservation Division said the goal of the plan is to reduce the risk of induced earthquakes in the Cushing area by changing the operations of the specified disposal wells. With the latest addition, the plan now calls for operational changes at a total of 13 disposal wells. Operators of 13 other disposal wells are being put on notice that changes may be required in the future.

The latest addition to the plan calls for disposal wells injecting into the Arbuckle formation to change operations based on the distance from the center of the recent earthquake activity. Wells within three miles must shut in and stop operations. wells within three to six miles must reduce injection volumes by 25%. Wells with six to 10 miles must prepare for the possible requirement of operational changes in the future.

Earlier this month, 11 minor earthquakes hit the Cushing area over the span of a week, the strongest of which was a 4.5-magnitude temblor recorded by the U.S. Geological Survey (USGS) Oct. 10 (see Shale Daily, Oct. 12). Last month, the OCC shut down two disposal wells and curtailed injections at three others in response to seismic activity (see Shale Daily, Sept. 21).

The issue is not new, and the OCC has been eyeing for more than a year injections into the Arbuckle formation as the potential cause (see Shale Daily, Oct. 31, 2014; July 7, 2014).

Tulsa-based Marjo Operating Co. Inc. is challenging the OCC action curtailing injection well operations. The company has said regulators adopted restrictions without considering their impact on producing oil and natural gas wells (see Shale Daily, Oct. 14).