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.