More Evidence Ties Ohio Quakes to Well Site
Pittsburgh Tribune-Review
4 January 2012
By Timothy Puko
A New Year's Eve earthquake in Youngstown occurred only 100 meters
from another quake a week earlier, providing more evidence that an
injection well in which a company was disposing wastewater from
oil and gas drilling is likely causing the tremors, a seismologist
studying the activity said on Tuesday.
Eleven earthquakes have struck the area since March, including the
strongest yet -- a 4.0 magnitude -- on Saturday. The quakes have
been getting larger over several months, and all happened near the
Northstar Disposal Services waste-injection well. That means
drilling fluid disposal there probably caused them, said John
Armbruster, a seismologist at Columbia University hired by the
state of Ohio.
The shaking could continue for months before the underground
pressure dissipates, said Armbruster, who is helping state
researchers collect and study the data. His team is trying to add
more instruments, record smaller quakes and study injection
patterns at the well, which could take months, he said.
The Ohio Department of Natural Resources and Gov. John Kasich's
office say no conclusive evidence links the seismic activity to
the injection well, but they agreed to shut it down as a safety
precaution and expanded a moratorium on nearby operations set to
open after Saturday's quake.
If the disposal well is causing the earthquakes, it's probably
because an unknown fault turned out to be nearby, Armbruster said.
Fluid could be seeping from the well bottom down into the fault.
That would essentially work like a hydraulic jack, pushing the
fault walls apart, leading them to slip and the earth to shake, he
added.
Pennsylvania gas drillers rely heavily on Ohio injection wells for
disposal of drilling waste, according to Pennsylvania Department
of Environmental Protection records. Chevron, Rex Energy Corp.,
EOG Resources Inc., Consol Energy and Vista Resources Inc. all
used the site that was shut down, according to Pennsylvania
records.
None of the companies detailed its alternative disposal plans. EOG
has made alternate arrangements for disposal and does not expect
any harm to its Marcellus shale operations, but the company gave
no further details in an e-mailed statement.
Timothy Puko can be reached at tpuko@tribweb.com or 412-320-7991.