New Study Predicts Frack Fluids Can Migrate to Aquifers Within Years


http://www.propublica.org/images/ngen/gypsy_big_image/gt_drilling_rig_night_
630x420_120501.jpg

A Cabot Oil and Gas hydraulic fracturing site on Jan. 17, 2012, in
Springville, Pa. (Spencer Platt/Getty Images)

by  <http://www.propublica.org/site/author/Abrahm_Lustgarten/> Abrahm
Lustgarten
ProPublica, May 1, 2012, 4:29 p.m.

http://www.propublica.org/article/new-study-predicts-frack-fluids-can-migrat
e-to-aquifers-within-years


A new study has raised fresh concerns about the safety of gas drilling in
the Marcellus Shale, concluding that fracking chemicals injected into the
ground could migrate toward drinking water supplies far more quickly than
experts have previously predicted.

More than 5,000 wells were drilled in the Marcellus between mid-2009 and
mid-2010, according to the study, which was published in the journal
<http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1745-6584;jsessionid=B
C23355888AE384813C75FF3AE8C10B9.d02t02> Ground Water two weeks ago.
Operators inject up to 4 million gallons of fluid, under more than 10,000
pounds of pressure, to drill and frack each well.



Scientists have theorized that impermeable layers of rock would keep the
fluid, which contains benzene and other dangerous chemicals, safely locked
nearly a mile below water supplies. This view of the earth's underground
geology is a cornerstone of the industry's argument that fracking poses
minimal threats to the environment.

But the study, using computer modeling, concluded that natural faults and
fractures in the Marcellus, exacerbated by the effects of fracking itself,
could allow chemicals to reach the surface in as little as "just a few
years."

"Simply put, [the rock layers] are not impermeable," said the study's
author, Tom Myers, an independent hydrogeologist
<http://water.nv.gov/hearings/past/springetal/browseabledocs/exhibits%5CCTGR
%20Exhibits/CTGR_EXH_006%20Statement%20of%20Qualifications%20of%20Tom%20Myer
s,%20Ph.D..PDF> whose clients include the federal government and
environmental groups.

"The Marcellus shale is being fracked into a very high permeability," he
said. "Fluids could move from most any injection process."

The research for the study was paid for by Catskill Mountainkeeper and the
Park Foundation, two upstate New York organizations that have opposed gas
drilling and fracking in the Marcellus.

Much of the  <http://www.propublica.org/series/fracking> debate about the
environmental risks of gas drilling has centered on the risk that spills
could pollute surface water or that structural failures would cause wells to
leak.

Though some scientists believed it was possible for fracking to contaminate
underground water supplies, those risks have been considered secondary. The
study in Ground Water is the first peer-reviewed research evaluating this
possibility.

The study did not use sampling or case histories to assess contamination
risks. Rather, it used software and computer modeling to predict how
fracking fluids would move over time. The simulations sought to account for
the natural fractures and faults in the underground rock formations and the
effects of fracking.

The models predict that fracking will dramatically speed up the movement of
chemicals injected into the ground. Fluids traveled distances within 100
years that would take tens of thousands of years under natural conditions.
And when the models factored in the Marcellus' natural faults and fractures,
fluids could move 10 times as fast as that.

Where man-made fractures intersect with natural faults, or break out of the
Marcellus layer into the stone layer above it, the study found,
"contaminants could reach the surface areas in tens of years, or less."

The study also concluded that the force that fracking exerts does not
immediately let up when the process ends. It can take nearly a year to ease.

As a result, chemicals left underground are still being pushed away from the
drill site long after drilling is finished. It can take five or six years
before the natural balance of pressure in the underground system is fully
restored, the study found.

Myers' research focused exclusively on the Marcellus, but he said his
findings may have broader relevance. Many regions where oil and gas is being
drilled have more permeable underground environments than the one he
analyzed, he said.

"One would have to say that the possible travel times for a similar thing in
Arkansas or Northeast Texas is probably faster than what I've come up with,"
Myers said.

Ground Water is the journal of the  <http://www.ngwa.org/Pages/default.aspx>
National Ground Water Association, a non-profit group that represents
scientists, engineers and businesses in the groundwater industry.

Several scientists called Myers' approach unsophisticated and said that the
assumptions he used for his models didn't reflect what they knew about the
geology of the Marcellus Shale. If fluids could flow as quickly as Myers
asserts, said Terry Engelder, a professor of geosciences at Penn State
University who has been a proponent of shale development, fracking wouldn't
be necessary to open up the gas deposits.

"This would be a huge fracture porosity," Engelder said. "So I read this and
I say, 'Golly, does this guy really understand anything about what these
shales look like?' The concern then arises from using a model rather than
observations."

Myers likened the shale to a cracked window, saying that samples showing it
didn't contain fractures were small in size and were akin to only examining
an intact section of glass, while a broader, scaled out view would capture
the faults and fractures that could leak.

Both scientists agreed that direct evidence of fluid migration is needed,
but little sampling has been done to analyze where fracking fluids go after
being injected underground.

Myers says monitoring systems could be installed around gas well sites to
measure for changes in water quality, a measure required for some gold
mines, for example. Until that happens, Myers said, theoretical modeling has
to substitute for hard data.

"We were trying to use the basic concepts of groundwater and hydrology and
geology and say can this happen?" he said. "And that had basically never
been done."