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Gas powers fracking plays

10th April 2013

Substituting diesel fuel with natural gas to power rigs and drilling units operating in North America’s shale hotspots is becoming an increasingly prevalent trend, as the resource proves to be a cleaner and more environmentally sustainable alternative

Gas powers fracking plays
Replacing diesel fuel with LNG can save companies as much as USD 660m per year, according to industry estimates

Unconventional gas is fast becoming the most prevalent source of natural gas in the US, now accounting for about a quarter of its production, up from just two per cent in 2000. This figure will double by 2035, according to the US Energy Information Administration (EIA). This ‘revolution’ has helped the country cut gas prices, reduce its energy imports and look with optimism at the prospect of future energy independence.

The boom is seeing a long list of operators, not just in US but also Canadian shale formations, increasingly turning from diesel fuel to natural gas as a more cost effective and environmentally friendly way to fuel their drilling rigs.

Gas power takes root

Colorado-based Energy Corporation of America (ECA) in 2011 launched a dual-fuel rig able to run on diesel or unprocessed natural gas (field gas), a move followed by US energy company Consol Energy, which now has two dual-fuel systems in operation in Pennsylvania. In West Virginia, oil and gas firm EQT Corp. is operating a rig powered by liquefied natural gas (LNG) and another by field gas from adjacent wells.

The trend quickly gathered momentum in 2012. In November, Seneca Resources Corp. and its partner, the drilling arm of Ensign Energy Services Inc. installed two of US firm General Electric’s (GE) Jenbacher gas engines to power the LNG fuelled drilling rigs in the Marcellus Shale region of Pennsylvania.

Seneca converted the power plants of two existing diesel-powered rigs to use cleaner-burning LNG in GE’s 1-megawatt Jenbacher J320 turbocharged natural gas engines. The first rig was converted in October and is operating in Lycoming County, Pennsylvania, while the second was converted to LNG in November and assigned to Seneca’s Marcellus Shale gas leases.

 “Our fuel-flexible Jenbacher gas engine technology offers customers lower-emission on-site power generating capabilities, making it ideally suited to support Seneca Resources and Ensign Drilling’s LNG initiative that will serve as a model for other operators in the Marcellus Shale region,” says Roger George, North America general manager of gas engines for GE Power & Water.

In addition, the LNG arm of Canadian energy services firm Ferus was engaged by a major oil and gas service company in the US to conduct a hydraulic fracturing operation in the US Eagle Ford Formation using LNG as an engine fuel. The project involved six dual-fuel 2,250 horsepower LNG-run pressure pumper units to stimulate well performance in the south Texas Eagle Ford Shale.

“LNG offers significant environmental and cost-saving advantages and is quickly becoming the alternative fuel of choice for heavy-duty high horsepower on-road and off-road applications in North America,” says Dick Brown, president and CEO of Ferus. “We were very pleased to play such a critical role in this ground-breaking project, and we intend to be at the forefront of this growing industry as more and more diesel consumers make the switch to North America’s abundant supply of natural gas.”

Giants follow trend

Texas-based oilfield services giant Baker Hughes has itself joined the diesel-to-gas campaign by converting a fleet of hydraulic fracturing units to bifuel pumps powered by natural gas and diesel, reducing diesel use by up to 65 per cent whilst maintaining hydraulic horsepower, the company claims. The converted fleet can also reduce nitrogen oxide, carbon dioxide and particulate matter emissions.

The conversion followed successful results from a similar initiative by the oilfield services company in Canada. Baker Hughes is in the process of converting several more fleets of Rhino trucks for bifuel usage.

“Baker Hughes has seen excellent results with this initiative,” says Mike Davis, Baker Hughes' president of Pressure Pumping for US land. “The environmental benefits are significant. We are reducing emissions from the engines driving the stimulation pumps and less fuel is needed to keep our pumps going.  In addition, this has the added value of improving job site safety by eliminating re-fuelling demands during operations.”

Baker Hughes’s new Rhino units were in a hydraulic fracturing job in the Eagle Ford Shale for energy firm Cheyenne Petroleum Company. Baker Hughes claims the 65 per cent cut in diesel fuel consumption can help the oil company achieve significant cost reductions.

In 2013, more oil and gas companies are embracing the rush for natural gas as a fuel for fracking treatment.

Already in January, US oilfield services company Halliburton developed dual-fuel technology to allow the pumping equipment used in a fleet of hydraulic fracturing rigs owned by Texas-based oil and gas exploration company Apache Corporation to process natural gas.

Halliburton converted 12 of Apache’s new Q-10 pumps to dual-fuel, enabling them to process not only diesel fuel but also cleaner US natural gas. Halliburton delivered the Q-10 pumps in April 2012.

The pumping equipment has a maximum pressure rating of 20,000 pounds per square inch, a range of rates between 2.7 and 18.9 barrels per minute, and a power rating of 2,000 hydraulic horsepower each, with all twelve pumps totalling 24,000 horsepower.

Halliburton teamed up with two other companies to see the project through: Caterpillar and Linde North America.

Machines and engines producer Caterpillar provided its proprietary dynamic gas blending (DGB) engine technology to power Halliburton’s massive pump.

“We anticipate that in the not-so-distant future, these DGB engines can be easily retrofitted to efficiently burn available on-site conditioned field gas, thereby saving operators additional fuel transport costs,” said Marc Edwards, senior vice president of Halliburton’s completion and production division.

Gas supplier Linde North America helped the US oilfield services company establish a gas distribution system and supplied the LNG needed for the project.

“Apache is proud to be setting an example for the industry by using a clean-burning, abundant and inexpensive US energy source in its operations,” says Mike Bahorich, Apache’s executive vice president and chief technology officer. “Taking advantage of natural gas can lead to cost savings for the industry and for energy consumers, new jobs and a cleaner environment – it’s time for us to use this resource to its full potential.”

Environmental benefits

The diesel-to-LNG shift is directly tied to enhanced cost efficiency as well as reduced carbon emissions.

Powering a drill rig with natural gas instead of diesel can result in 60 per cent lower fuel costs, according to GE. Industry estimates suggest using field gas to fuel one rig can save companies over USD 1m per year,  and Denver based rig operator Ensign Energy Services states that LNG does not lag far behind, saving as much as USD 660m. In terms of its impact on the environment, a natural gas rig is reported to emit 20 to 30 per cent less carbon dioxide, and only a small fraction of the nitrogen oxides, sulphur oxides and particulates.

Ensign, who operates 15 drilling rigs on natural gas in the US, estimates that if every onshore drilling unit in the country were converted from diesel to natural gas, it would reduce nitrogen oxide emissions by 250,000 tonnes per annum and particulate emissions by 6,300 tonnes per year.