LITTLE ROCK, Ark. – The U.S. Geological Survey recorded Thursday-morning earthquakes with preliminary magnitudes of 3.7 and 3.2. The earthquakes come a day after the Arkansas Oil and Gas Commission said it will consider temporarily shutting down two injection wells linked to quakes that have shaken the state.
The wells are used by the natural gas industry for wastewater from production. The Oil and Gas Commission's staff requested that two wells be shut down until the panel can reconsider the matter at a March 29 meeting. The emergency meeting is scheduled for Friday.
"I can't go into detail at this time, but I can say that we believe there is a potential correlation between injection operations and earthquakes at one or both of those wells," said Shane Khoury, deputy director and general counsel for the commission.
One of the wells is outside Guy and is owned by Chesapeake Operating Inc. The other near Greenbrier is owned by Clarita Operating LLC.
Chesapeake Energy said it believes its wells are safe and that it would continue to provide information to the commission.
"We remain very confident that an objective review of the facts and science do not support the proposed action," Danny Games Sr., director of corporate development, said in a written statement. "We have dedicated extensive resources and have consulted with several very qualified geophysicists and seismologists to better understand the science, including the natural seismicity of the area that long pre-dates our operations."
Matthew Miles, manager of the Clarita injection well site, declined comment Wednesday evening and referred inquiries to the company's home office in Ada, Okla. A telephone call to the company reached a recording that offered no voice-mail option.
The companies can make presentations during Friday's meeting.
Geologists have been studying a swarm of recent quakes -- most of them tiny -- in the Greenbrier-Guy area for months in an attempt to determine if there is a connection between the seismic activity and activities of gas-drilling companies in the Fayetteville Shale formation. Sunday night, a 4.7-magnitude earthquake -- the most powerful reported in the state in 35 years -- struck near Greenbrier.
Khoury said the Arkansas Geological Survey has conducted studies in partnership with the commission staff.
Scott Ausbrooks, a seismologist from the survey, said he could not comment on the specifics of his agency's findings until after his presentation to the commission on Friday, but he said the two wells cited in the commission announcement are closest to the quakes.
The area of north-central Arkansas that includes Guy and Greenbrier -- less than 10 miles apart in northern Faulkner County -- has endured more than 800 earthquakes over the past six months. Seismologists say the quakes are not connected to the New Madrid Fault, a historically active fault in northeast Arkansas, more than 200 miles away.
ajor source of natural gas in Arkansas is the Fayetteville Shale, an organically-rich rock formation underlying the region. Drillers free up the gas by using hydraulic fracturing or "fracking" -- injecting pressurized water to create fractures deep in the ground. The two injection wells at issue dispose of waste "frack" water when it can no longer be re-used, by injecting it into the ground under pressure.
Gov. Mike Beebe said he supported the commission's decision to take a close look at the injection wells.
"I'm going to listen to the scientists, and if the scientists say that it's worth making some changes in the areas where they think changes should be made, then I'm going to listen to our scientists and support them," Beebe told reporters at the state Capitol.
If the commission decides to shut down the two injection well operations, the order could take effect Friday and stay in force until the commission's next scheduled meeting on March 29.
A six-month moratorium was established in January on new injection wells in the area to allow time to study the relationship -- if any -- between the wells and the earthquakes. The emergency order would not affect the five other injection wells currently operating in that region, Khoury said.