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7/19/13, "Study finds fracking chemicals didn't pollute water: AP," AP via CBS News
"A landmark federal study on hydraulic fracturing, or fracking, shows
no evidence that chemicals from the natural gas drilling process moved
up to contaminate drinking water aquifers at a western Pennsylvania
drilling site, the Department of Energy told The Associated Press.
After
a year of monitoring, the researchers found that the chemical-laced
fluids used to free gas trapped deep below the surface stayed thousands
of feet below the shallower areas that supply drinking water, geologist
Richard Hammack said.
Although the results are
preliminary -- the study is still ongoing -- they are a boost to a
natural gas industry that has fought complaints from environmental
groups and property owners who call fracking dangerous.
"This is good news," said Duke University scientist Rob Jackson, who
was not involved with the study. He called it a "useful and important
approach" to monitoring fracking, but cautioned that the single study
doesn't prove that fracking can't pollute, since geology and industry
practices vary widely in Pennsylvania and across the nation.
The
boom in gas drilling has led to tens of thousands of new wells being
drilled in recent years, many in the Marcellus Shale formation that lies
under parts of Pennsylvania, New York, Ohio and West Virginia. That's
led to major economic benefits but also fears that the chemicals used in
the drilling process could spread to water supplies.
The
mix of chemicals varies by company and region, and while some are
openly listed, the industry has complained that disclosing special
formulas could violate trade secrets. Some of the chemicals are toxic
and could cause health problems in significant doses, so the lack of
full transparency has worried landowners and public health experts.
Drilling
fluids tagged with unique markers were injected more than 8,000 feet
below the surface, but were not detected in a monitoring zone 3,000 feet
higher. That means the potentially dangerous substances stayed about a
mile away from drinking water supplies.
The study, done by the National Energy Technology Laboratory in
Pittsburgh, marked the first time that a drilling company let government
scientists inject special tracers into the fracking fluid and then
continue regular monitoring to see whether it spread toward drinking
water sources. The research is being done at a drilling site in Greene
County, which is southwest of Pittsburgh and adjacent to West Virginia.
Eight
new Marcellus Shale horizontal wells were monitored seismically and one
was injected with four different man-made tracers at different stages
of the fracking process, which involves setting off small explosions to
break the rock apart. The scientists also monitored a separate series of
older gas wells that are about 3,000 feet above the Marcellus to see if
the fracking fluid reached up to them.
The industry and
many state and federal regulators have long contended that fracking
itself won't contaminate surface drinking water because of the extreme
depth of the gas wells. Most are more than a mile underground, while
drinking water aquifers are usually within 500 to 1000 feet of the
surface....
While
the lack of contamination is encouraging, Jackson said he wondered
whether the unidentified drilling company might have consciously or
unconsciously taken extra care with the research site, since it was
being watched. He also noted that other aspects of the drilling process
can cause pollution, such as poor well construction, surface spills of
chemicals, and wastewater.
Jackson and his colleagues at
Duke have done numerous studies over the last few years that looked at
whether gas drilling is contaminating nearby drinking water, with mixed
results. None of them have found chemical contamination, but they did
find evidence that natural gas escaped from some wells near the surface
and polluted drinking water in northeastern Pennsylvania.
Scott Anderson, a drilling expert with the Environment Defense Fund, said the results sound very interesting.
"Very few people think that fracking at significant depths routinely
leads to water contamination. But the jury is still out on what the odds
are that this might happen in special situations," Anderson said.
One
finding surprised the researchers: Seismic monitoring determined one
hydraulic fracture traveled 1,800 feet out from the well bore; most
traveled just a few hundred feet. That's significant, because some
environmental groups have questioned whether the fractures could go all
the way to the surface.
The researchers believe that
fracture may have hit naturally occurring faults, and that's something
both industry and regulators don't want.
"We would like to be able to predict those areas" with natural faults and avoid them, Hammack said. Jackson said the 1,800-foot fracture was very interesting, but also noted it is still a mile from the surface.
The
DOE team will start to publish full results of the tests over the next
few months, said Hammack, who called the large amount of field data from
the study "the real deal." "People probably will be looking at the data for years to come," he said." via Free Republic
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