Scientific Peer Reviewed Study

[John Mayo]

When reading this article, remember that injection wells are ongoing
fracked wells as long as they are in use. I also suppose they remain
under pressure after they are shut down and (hopefully) properly
plugged, (as all wells in Texas should be, but regrettably aren't).
John Mayo.


Scientific Study Links Flammable Drinking Water to Fracking
Tuesday 10 May 2011
by: Abrahm Lustgarten, ProPublica

(Photo: danielfoster437/Flickr.)
For the first time, a scientific study has linked natural gas drilling
and hydraulic fracturing with a pattern of drinking water
contamination so severe that some faucets can be lit on fire.
The peer-reviewed study, published today in the Proceedings of the
National Academy of Sciences, stands to shape the contentious debate
over whether drilling is safe and begins to fill an information gap
that has made it difficult for lawmakers and the public to understand
the risks.
The research was conducted by four scientists at Duke University. They
found that levels of flammable methane gas in drinking water wells
increased to dangerous levels when those water supplies were close to
natural gas wells. They also found that the type of gas detected at
high levels in the water was the same type of gas that energy
companies were extracting from thousands of feet underground, strongly
implying that the gas may be seeping underground through natural or
manmade faults and fractures, or coming from cracks in the well
structure itself.
“Our results show evidence for methane contamination of shallow
drinking water systems in at least three areas of the region and
suggest important environmental risks accompanying shale gas
exploration worldwide,” the article states.
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The group tested 68 drinking water wells in the Marcellus and Utica
shale drilling areas in northeastern Pennsylvania and southern New
York State. Sixty of those wells were tested for dissolved gas. While
most of the wells had some methane, the water samples taken closest to
the gas wells had on average 17 times the levels detected in wells
further from active drilling. The group defined an active drilling
area as within one kilometer, or about six tenths of a mile, from a
gas well.
The average concentration of the methane detected in the water wells
near drilling sites fell squarely within a range that the U.S
Department of Interior says is dangerous and requires urgent “hazard
mitigation” action, according to the study.
The researchers did not find evidence that the chemicals used in
hydraulic fracturing had contaminated any of the wells they tested,
allaying for the time being some of the greatest fears among
environmentalists and drilling opponents.
But they were alarmed by what they described as a clear correlation
between drilling activity and the seepage of gas contaminants
underground, a danger in itself and evidence that pathways do exist
for contaminants to migrate deep within the earth.
“We certainly didn’t expect to see such a strong relationship between
the concentration of methane in water and the nearest gas wells. That
was a real surprise,” said Robert Jackson, a biology professor at Duke
and one of the report’s authors.
Methane contamination of drinking water wells has been a common
complaint among people living in gas drilling areas across the
country. A 2009 investigation by ProPublica revealed that methane
contamination from drilling was widespread, including in Colorado,
Ohio and Pennsylvania. In several cases, homes blew up after gas
seeped into their basements or water supplies. In Pennsylvania a 2004
accident killed three people, including a baby.
In Dimock, Pa., where part of the Duke study was performed, some
residents’ water wells exploded or their water could be lit on fire.
In at least a dozen cases in Colorado, ProPublica’s investigation
found, methane had infiltrated drinking water supplies that residents
said were clean until hydraulic fracturing was performed nearby.
The drilling industry and some state regulators described some of
these cases as “anecdotal” and said they were either unconnected to
drilling activity or were an isolated problem. But the consistency of
the Duke findings raises questions about how unusual and widespread
such cases of methane contamination may be.
“It suggests that at least in the region we looked, this is a more
general problem than people expected,” Jackson told ProPublica.
For those who live in the midst of this problem, the report serves as
long-awaited vindication. “We weren’t just blowing smoke. What we were
talking about was the truth,” said Ron Carter, a Dimock resident whose
water went bad when drilling began there in 2008 and was later tested
as part of the study. “Now I’m happy that at least something helps
prove out our theory.”
Methane is not regulated in drinking water, and while research is
limited, it is not currently believed to be harmful to drink. But the
methane is dangerous because as it collects in enclosed spaces it can
asphyxiate people nearby, or lead to an explosion.
To determine where the methane in the wells they tested came from, the
researchers ran it through a molecular fingerprinting process called
an isotopic analysis. Water samples furthest from gas drilling showed
traces of biogenic methane—a type of methane that can naturally appear
in water from biological decay. But samples taken closer to drilling
had high concentrations of thermogenic methane, which comes from the
same hydrocarbon layers where gas drilling is targeted. That—plus the
proximity to the gas wells—told the researchers that the contamination
was linked to the drilling processes.
In addition to the methane, other types of gases were also detected,
providing further evidence that the gas originated with the
hydrocarbon deposits miles beneath the earth and that it was unique to
the active gas drilling areas. Ethane, another component of natural
gas, and other hydrocarbons were detected in 81 percent of water wells
near active gas drilling, but in only 9 percent of water wells further
away. Propane and butane were also detected in some drilling area
wells.
The report noted that as much as a mile of rock separated the bottom
of the shallow drinking water wells from the deep zones fractured for
gas, and identified several ways in which fluids or the gas
contaminants could move underground: The substances could be displaced
by the pressures underground; could travel through new fractures or
connections to faults created by the hydraulic fracturing process; or
could leak from the well casing itself somewhere closer to the
surface.
The geology in Pennsylvania and New York, they said, is tectonically
active with faults and other pathways through the rock. They noted
that leaky well casings were the most likely cause of the
contamination, but couldn’t rule out long-range underground migration,
which they said “might be possible due to both the extensive fracture
systems reported for these formations and the many older, uncased
wells drilled and abandoned.”
The water was also analyzed for signs that dangerous fluids from
inside the gas wells might have escaped into water supplies. The group
tested for salts, radium and other chemicals that, if detected, would
have signaled that the produced water or natural fluids in the well’s
target zone were making it to the aquifers. But those types of fluids
were not found. The group did not test for fracking chemicals or
hydrocarbons like benzene, relying instead on the saline or
radioactive compounds like radium as indicators.
In an interview, Jackson said that gas was more likely to migrate
underground than liquid chemicals. Based on his findings, he doesn’t
believe the toxic chemicals pumped into the ground during fracturing
are likely to end up in water supplies the same way the methane did.
“I’m not ready to use the word impossible,” he said, “but unlikely.”
In a white paper the group issued along with the journal article,
Jackson and the others acknowledged the uncertainty and called for
more research. “Contamination is often stated to be impossible due to
the distance between the well and the drinking water,” they wrote.
“Although this seems reasonable in most (and possibly all) cases,
field and modeling studies should be undertaken to confirm this
assumption… Understanding any cases where this assumption is incorrect
will be important—when, where, and why they occur—to limit problems
with hydraulic fracturing operations.”
A hydrogeologist closely affiliated with the drilling industry raised
questions about the study. "It's possible, assuming their measurements
are accurate, that all they have done is document the natural
conditions of the aquifer," said John Conrad, president of Conrad
Geosciences in Poughkeepsie, N.Y. Conrad spoke with ProPublica at the
suggestion of Energy In Depth, a drilling industry advocacy group, but
said that he did not work for EID.
He said that the thermogenic methane -- which many scientists say
comes from the same deep gas layers where drilling occurs -- could be
naturally occurring. He also said the researchers didn't test enough
wells to support their conclusions, though he could not say how many
wells would have been appropriate.
Conrad said the most likely cause for the contamination identified by
the Duke researchers -- that the gas was leaking out of faulty well
casings -- seemed implausible.
"For their assumptions to hold up there would have to be more than
just the occasional bad cement job," he said. "They are implying that
where you see hydraulic fracturing you should expect to see elevated
methane. We are aware of faulty cement jobs. But we don't believe that
it is common and we certainly don't believe that it is universal."
The Duke study precedes a national study by the Environmental
Protection Agency into the dangers of hydraulic fracturing that is
expected to be finished sometime next year. Last year the EPA found
that some chemicals known to be used in fracturing were among the
contaminants detected in 11 residential drinking water wells in
Pavillion, Wy.—where more than 200 natural gas wells have been drilled
in recent years—but that investigation is continuing and the
scientists haven’t concluded that the contamination is linked with
drilling or hydraulic fracturing.
The release of the Duke research could immediately shape the
increasingly intense public debate over drilling and hydraulic
fracturing, especially in some of the areas where the research was
conducted. Pennsylvania, which holds drilling companies liable for
drinking water contamination within 1000 feet of a gas well, might
consider the fact that the Duke researchers found the contamination
extended to about 3,000 feet, Jackson said. New York State has a
moratorium in place for hydraulic fracturing of horizontally-drilled
wells—which cover more area and require more chemicals—through the end
of June to allow for more consideration of the risks. “I would extend
that at least temporarily,” Jackson said.
Congress, too, is taking note.
"This study provides eye-opening scientific evidence about methane
contamination and the risks that irresponsible natural gas drilling
poses for drinking water supplies,” said Congressman Maurice Hinchey,
D-NY. “It provides yet another reason why more study of the
environmental and health risks associated with hydraulic fracturing is
needed."
Hinchey is one of several Democratic members of Congress who recently
re-introduced the FRAC Act, which calls for public disclosure of the
chemicals used underground. The bill, which is currently languishing
in the House, would remove an exemption in federal law that prohibits
the EPA from regulating hydraulic fracturing.
May 9: This story has been updated to include information from John
Conrad that was received after publication.