Oklahoma City-based Chesapeake Operating Inc. and Little Rock, AR-based Clarita Operating LLC agreed Friday to halt drilling waste injection activities at two disposal wells while a potential link between injection activities and earthquakes in the Fayetteville Shale region is examined.

The Arkansas Oil and Gas Commission (AOGC) held an emergency meeting to consider a staff request that injections at the two wells be halted, and commissioners unanimously approved the emergency order sought by AOGC Director Larry Bengal to immediately stop all injection operations at the two disposal wells in Faulkner County.

The companies volunteered to stop injections until the matter can be discussed at the AOGC’s regular meeting, which is scheduled for March 29. Since last summer the Fayetteville Shale region has experienced numerous small earthquakes. A recent larger quake heightened concerns that the seismic activity could be caused by injection wells (see Shale Daily, March 4).

“The staff of the AOGC and the Arkansas Geological Survey (AGS) have found no correlation between seismic activity and the drilling, or completion (including fracture stimulation) of production wells,” the commission said. “However, it is the opinion of the staff of the AOGC, based upon research by the AGS and the Center for Earthquake Research and Information (CERI), that there is circumstantial evidence which supports a temporary shutdown of the two above referenced disposal wells.

“An interpretation of the preliminary information obtained in accordance with AOGC Order No. 602A-2010-12 shows a potential correlation between injection operations in one, or both, of these two disposal wells and the seismic activity in the area.”

Bengal requested an emergency order due to the apparent existence of a previously unknown or unmapped fault highlighted by the recent seismic activity, as interpreted by CERI, upon which both of these two disposal wells are located in, or nearby, the commission said.

Chesapeake and Clarita agreed to cease injection operations in the two disposal wells, without agreeing with the position that there may be a potential correlation between the wells and seismic activity in the area.

Bengal is expected to file an application requesting an extension of the cessation order, including a presentation of evidence of the potential correlation between injection operations in the disposal wells and seismic activity in the area at the next AOGC hearing beginning on March 29. Chesapeake and Clarita will have the opportunity to present evidence at the hearing.