Ohio Closes Wastewater Disposal Wells After Earthquakes

Pittsburgh Post-Gazette
3 January 2012
By Don Hopey

A series of earthquakes in northwestern Ohio, the latest and largest on New Year's Eve, has prompted that state's Department of Natural Resources to close or suspend development by natural gas drillers of five deep wastewater disposal wells pending an investigation into well impact on increased seismic activity in the area.

The latest earthquake, registering a magnitude of 4.0, was centered five miles northwest of Youngstown and very close to the 9,000-foot-deep Northstar No. 1 disposal well owned by D&L Energy, which receives most of its brine and fracking wastewater from Marcellus Shale drilling operations in Pennsylvania.

The Ohio DNR had halted wastewater injections at the Northstar disposal well Friday after analyzing new seismic data from a 2.7-magnitude Dec. 24 earthquake, one of 10 smaller tremors that occurred in the area during 2011.

After the New Year's Eve quake, which occurred at 3:05 p.m. and rattled dishes but caused no structural property damage or injuries, the DNR also halted development of four new wastewater injection wells within 5 miles of the Northstar well that were slated to open for business in the next few weeks.

"We evaluated the new research, and it shows the Dec. 24 seismic event occurred within 2,000 feet of the well injection point," said Andy Ware, Ohio DNR deputy director. "We can't say for sure that it's linked to the well, but we'll keep the operations shut down for an indefinite period until we can get an accurate picture of what's going on here. We think that's a prudent and proper response to protecting the health and safety of Ohio residents."

A 4.0-magnitude earthquake has a seismic energy yield equivalent to detonating 15 metric tons of dynamite or a small atomic bomb.

Ohio has 177 Class II deep injection wells, between 5,000 and 9,000 feet deep, for disposal of brine, produced water and drilling wastewater into deep sandstone and limestone formations. Pennsylvania has six.

A secretary answering the phone at D&L Energy said the company is declining comment and referred questions to the Ohio Oil and Gas Association, which, in a statement Sunday, said it supported the DNR well closures to "ensure the safety and peace of mind for area residents."

"We believe the situation in Youngstown is a rare and isolated event that should not cast doubt about the effectiveness or usage of Class II injection wells, which have been used safely and reliably as a disposal method for wastewater from oil and gas operations in the U.S. since the 1930s and is the preferred method for oilfield waste management under the Safe Drinking Water Act," Thomas Stewart, OOGA executive vice president, said in the release. He added that any decisions about continued operation of the disposal wells should be based on "sound, scientific principles."

The DNR hired earthquake experts from Columbia University's Lamont-Doherty Earth Observatory in New York earlier this year to monitor the tremors and gather data using portable seismographs. Those experts, who recommended the closure of the five injection wells, said there's little doubt that the tremors were caused by the Northstar well, based on their location and pattern of seismic activity.

"Our monitors were able to locate the epicenter within a half mile of the injection well and at a depth of about two miles, which if the injection wells were to cause it, it usually would occur at that depth," said Won-Young Kim, a professor of seismology geology and tectonophysics at Lamont-Doherty. "Youngstown is not a seismicly active area, but fluid could migrate to an area where a pre-existing fault is located."

Mr. Kim said the series of lesser tremors followed by the larger earthquake near Youngstown is a "carbon copy" of what occurred around deep injection wells near Ashtabula, Ohio, in the northeast corner of the state near Lake Erie. There, a series of lesser tremors over several years culminated in a 4.5-magnitude earthquake in January 2001, two to three years after the wells had shut down.

A similar pattern of what Mr. Kim termed "induced seismicity" occurred near Denver, Colo., at the Rocky Mountain Arsenal where an almost 12,000-foot-deep injection well drilled in 1961 induced a series of tremors the following year that topped out at a magnitude of 5.5 in 1963.

Leonardo Seeber, another Lamont-Doherty research professor familiar with Ohio geologic formations, said given what is known about the area's geology and its seismic history, closing the injection wells and gathering and analyzing additional data is appropriate.

"I don't like the turn-a-blind-eye approach that doesn't accept that this type of trigger is possible," Mr. Seeber said. "We need to acknowledge that as we increase fracking on the Appalachian Plateau in Pennsylvania and Ohio that we are doing the kind of waste disposal that is increasing the probability of seismic activity around these waste injection wells."

He said all disposal wells should be required to monitor seismic activity in their area and inform regulatory officials if it occurs. Mr. Ware said Ohio is considering such a requirement for new waste injection wells.

"The basement rock there, the Granville, is very old and full of fractures," Mr. Seeber said. "We know the stress is pushing it close to its limits, so if we go down there and change things by injecting, there's a good possibility we could trigger an earthquake. We should assume faults are everywhere."

Don Hopey: dhopey@post-gazette.com or 412-263-1983.