* Environmentalists, oil patch at odds over safety
* Precise studies have yet to be done
* Engineers can't see major differences in crudes
By Jeffrey Jones and Timothy Gardner
CALGARY/WASHINGTON, Aug 2 A recent series of
oil spills has amplified a debate over the safety of shipping
oil sands-derived crude through pipelines, but there is little
hard evidence that the Canadian oil is more corrosive than
conventional crude, scientists and regulators say.
Environmental groups, led by the New York-based Natural
Resources Defense Council (NRDC), contend that the oil from the
Alberta tar sands, when blended with light hydrocarbons to
allow it to flow, eats away at the insides of long-haul
pipelines because of its high acidity and mineral content.
It is one argument they use in their staunch opposition to
TransCanada Corp's (TRP.TO) $7 billion Keystone XL pipeline to
Texas from Alberta, now being reviewed by the U.S. State
Department. It arose again after a pipeline to an Exxon Mobil
(XOM.N) refinery in Montana burst last month.
Keystone XL would add more than half a million barrels per
day of Canadian oil exports to the United States and, its
proponents say, that would enhance U.S. energy security.
TransCanada and petroleum industry groups say there is no
evidence that shipping oil sands crude over long distances is
more dangerous than moving any other fossil fuel, arguing that
it would be pointless to spend all that money on a mega-project
knowing that it would fail.
Experts are hard-pressed to say if the crude mixture, known
as dilbit, weakens the interior walls of pipelines quicker than
other oil does. Some are surprised there has been no specific
study to link oil sands crude and pipeline corrosion.
"I'm not aware of any significant differences in terms of
corrosion or anything like that," said Harvey Yarranton, an
engineering professor and heavy oil specialist at the
University of Calgary's Shulich School of Engineering.
"For the heavy oils and bitumens, the biggest difference is
they are much richer in the heavy components than the light
components." Light components are more volatile, so they
vaporize more quickly, he said.
TRANSPORT, REFINING DIFFER
Environmental groups argue the petroleum has a high sulfur
content compared with other crudes, and that can corrode
pipelines faster. They also say it is more viscous than most
other crudes, which causes friction and raises the temperature
within pipelines, and that dilbit contains bits of quartz an
other rocks that can damage pipelines.
The groups rely mostly on industry documents, books, and
reports in making conclusions rather than specific scientific
studies of the pipelines.
The NRDC, in a report issued earlier this year, pointed out
that material from petroleum service provider Baker Hughes
shows that heavier, higher-sulfur Canadian crudes are harder on
refinery equipment than conventional oil, requiring desalting,
corrosion- and fouling-control programs.
However, crude reacts differently in refining than it does
in transport, Yarranton said.
"Refineries are at much higher temperatures, so that's a
big difference. They are also reacting materials and creating
components in the mixture," he said. "The biggest difference is
they need equipment to handle the heavy components because
those components tend to form coke."
The report also relied on a page in a 1992 book by Russell
Jones called "Stress Corrosion Cracking Materials Performance
and Evaluation," which suggested high-sulfur crude can lead to
problems when exposed to steel. Jones told Reuters that it can
be a concern in pipelines, but he was not aware of it causing a
"Corrosion that has caused pipeline leaks is always from
the outside in. I can't think of a case where it was from the
inside out," he said.
Still, the NRDC and other groups argue there is enough
doubt and have urged the Pipeline Hazardous Materials and
Safety Administration, or PHSMA, a division of the U.S.
Transportation Department, to conduct an independent,
peer-reviewed study on how oil sands petroleum affects
'EASIER TO STOP AN ACCIDENT'
"There have been no independent studies on the impacts of
oil sands on pipelines ... essentially there are numerous
indications this stuff is a problem," said Anthony Swift, an
"It's much easier to stop an accident from happening than
to clean one up after it's happened," said Swift.
The National Energy Board, Canada's main energy regulator,
has already approved the Canadian portion of Keystone XL, and
the prospect of oil sands crude being more corrosive as
contended by green groups did not arise as an issue, said
Adrian Luhowy, senior engineer at the NEB.
"I think that's interesting, given that I am an engineer,"
he said. "I can't say definitely that they're 100 percent
wrong, I just have never seen any evidence to prove that."
Luhowy said design codes for pipelines vary based on the
materials they transport. That includes wall thickness and
other variables including how long it would take to respond if
there was a rupture.
He points out that many of the impurities in the heavy
crudes are removed before being transported in long-haul
pipelines, making them more like conventional oil, even if they
are not upgraded into synthetic light oil.
Still, Luhowy said he would be interested in seeing the
results of a study of the issue.
(Editing by Rob Wilson)