Study Links Fouled Water, Methane
Duke U. researchers find similar effects in Pa., N.Y. shale drilling
Pittsburgh Post-Gazette
10 May 2011
By Don Hopey and Laura Olson
A Duke University study has documented the first systematic link
between methane gas from deep Marcellus and Utica shales and
contamination of drinking water wells near active gas wells in
northeastern Pennsylvania and New York.
The study found that methane levels in private drinking water wells was
17 times higher on average in wells within 1,000 feet of a deep natural
gas well, based on water sampling done at 68 wells. Methane was found
in 85 percent of the wells.
Duke researchers were able to match the chemical composition of the
methane in three of the drinking water wells to the methane present in
three of the nearby gas wells, according to the study abstract.
Robert B. Jackson, a professor of biology in Duke's Nicholas School of
the Environment and one of the study's authors, said that in those
three instances the chemical analysis supported the claims of
landowners that their wells were contaminated by Marcellus Shale well
drilling.
"Based on the chemical isotope, the signature of the methane is much
more like the gas deep underground," said Mr. Jackson, who conceded
that the Marcellus gas was "quite variable, that the researchers only
had actual chemical gas values for three of the deep gas wells, and
that additional study is needed. Still, the water wells match quite
well what that data shows."
Gas from the Marcellus Shale is typically about 90 percent methane.
The study found no evidence of contamination of drinking water wells
with either salty brines from the mile-deep Marcellus Shale formation
or chemicals used in hydraulic fracturing, a procedure that pumps
water, toxic chemicals and sand into the shale to crack it and release
the gas it contains.
The study was published in the online Early Edition of the Proceedings
of the National Academy of Sciences.
John Hanger, former secretary of the Department of Environmental
Protection, said the study confirmed two points that the agency already
knew: that gas migration has impacted some water wells, and that no
fracking fluid has polluted those wells.
That was the case with incidents of well-water contamination in the
northeastern Pennsylvania town of Dimock, Mr. Hanger said. Faulty
drilling procedures and improper well casing resulted in methane gas
migrating to the water wells of 19 families.
In the Dimock case, most of the wells showed an immediate reduction in
methane after the nearby gas wells were plugged and repaired. "If the
fracking had been the cause," instead of problems with cement around
the well, "that wouldn't have been the case," Mr. Hanger said.
The Dimock migration case also resulted in stronger rules for how wells
are constructed, governing the materials and design as well as
disclosure of the chemicals used in the fracturing process, he said. It
also gave the department the power to impose stronger precautions in
areas like the state's northeast, where the geological conditions make
gas migration more likely than in southwestern Pennsylvania.
"I think the new rules will greatly reduce the incidents and rate of
gas migration," Mr. Hanger said, adding that those rules would need to
be vigorously enforced.
Katy Gresh, spokeswoman for the state Department of Environmental
Protection, said the agency was reviewing the report. "They would like
to see all of the authors' backup data to review their methodology,"
she said in a statement
Industry sources questioned the objectivity of the study authors as
well as their findings.
"Pennsylvania has an extensive and well-documented history of naturally
occurring methane impacting private water wells, long before Marcellus
development began just a few years ago," said Kathryn Klaber, president
of the Marcellus Shale Coalition, a gas industry lobbying organization.
She labeled the report "at best inconclusive," and noted that it was
edited by an "outspoken natural gas production critic."
Matt Pitzarella, a spokesman for Range Resources, one of the biggest
Marcellus Shale gas drillers in southwestern Pennsylvania, said several
parts of the study were "questionable or incomplete" but added that the
company supports best practices on construction of well casings.
Don Hopey: dhopey@post-gazette.com or 412-263-1983. Laura Olson:
lolson@post-gazette.com or 1-717-787-4254.