HARRISBURG, Pa. (AP) —
Advances in hydraulic fracturing technology have powered the American
natural gas boom. And now hydraulic fracturing could be increasingly
powered by the very fuel it has been so successful in coaxing up from
the depths.
Oil- and gas-field companies from Pennsylvania to
Texas are experimenting with converting the huge diesel pump engines
that propel millions of gallons of water, sand and chemicals thousands
of feet down well bores to break apart rock or tight sands and release
the natural gas trapped inside.
It's the latest way for drillers
to become consumers of the product that they are making broadly
available in large amounts — and extremely cheap. Production has
increased so much that natural gas has flooded the market, dragging down
prices and forcing companies to pull back on their plans to expand
drilling while looking for new ways to use gas.
After the
conversion, the engines will run on cheaper natural gas, or a blend of
diesel and natural gas. That brings down costs and, theoretically, cuts
down the sooty exhaust that comes from burning diesel.
"You're
going to see this spreading quite rapidly across the industry," said
Douglas E. Kuntz, president and CEO of Pennsylvania General Energy Co.,
based in tiny Warren, Pa. "As the technology evolves, you'll see more
companies across the country doing more natural gas fueling of this
equipment."
A number of increasingly cost-conscious oil- and
gas-field companies are already using natural gas to run their trucks
and drilling rigs. But what makes the conversion of the hydraulic
fracturing pump engines to natural gas particularly challenging is the
sheer number of engines running at once, and the amount of horsepower
necessary to power the pumps.
PGE and contractor Universal Well
Services, of Meadville, Pa., are converting a 16-engine pumping unit —
called a "frack spread" — so that the engines will accept a blend of 70
percent natural gas and 30 percent diesel. It should be complete by May
and is estimated to cost less than a quarter of what it would if it was
powered by diesel alone.
Houston-based Apache Corp., one of the
nation's largest independent oil and gas exploration companies, has
worked with Halliburton Co., Schlumberger Ltd. and Caterpillar Inc. to
develop similar technology.
A 12-engine unit — the first full
frack spread that is operating in the field, according to Apache — just
completed two Granite Wash wells near Elk City, Okla. Another unit is in
the process of being completed.
"Today we've said, 'we've seen
enough testing.' We've decided this is how we want to frack with all of
our fleets and we're going to start with two permanent conversions,"
said Mike Bahorich, Apache's executive vice president and chief
technology officer.
PGE will be able to use field gas, drawn from
pipelines that connect to its nearby Marcellus Shale wells in
north-central Pennsylvania, and save trips by fuel-hauling trucks. For
now at least, Apache will have to truck in compressed natural gas or
liquefied natural gas to run its new frack spreads, but it hopes to
start using the cheaper field gas in the future, Bahorich said.
It
also may provide a way for drilling companies to improve their image on
environmental issues after sustaining criticism for air quality
problems around gas wells and the practice of lacing hydraulic
fracturing fluids with chemicals.
The U.S. Environmental
Protection Agency calls reducing pollution from diesel engines one of
the county's most important air quality challenges. Diesel engines can
produce large quantities of smog-forming nitrogen oxides and soot, which
can cause lung and heart problems. Soot also plays a significant role
in climate change, researchers say.
Saving the truck trips will
improve air quality, but the size of the benefit from replacing diesel
engines with natural gas is less clear, according to environmental
advocates.
That's because new diesel engines are subject to strict
environmental standards and natural gas-powered engines give off only
slightly less pollution, said Joe Osborne, legal director of the
Pittsburgh-based Group Against Smog and Pollution.
Regardless, the
economic benefit appears enormous for an industry that used more than
700 million gallons of diesel domestically in hydraulic fracturing last
year, according to Apache estimates.
The cost to convert the
engines is far less than the roughly $3.5 million per frack spread that
Apache can save if it completes 140 planned wells in a year with the two
units, Bahorich said.
For PGE and Universal, the cost of
conversion and engineering will be several million dollars, said Roger
Willis, Universal's president. After that, the fuel price savings are
eye-popping: A gallon of diesel fuel costs about $3.60, while equivalent
amount of the natural gas blend replacement currently costs about 47
cents, Kuntz said.
PGE, which plans to drill 35 to 40 new
Marcellus Shale wells in 2013 all with the natural gas-powered frack
spread, expects to save 750,000 gallons of diesel a year, or 55 percent
of the diesel in its fracking operations.
"Keeping this frack spread busy over the course of a year, you'll be on the positive side in less than a year," Kuntz said.
Copyright 2013 The Associated Press.