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Gas-powered drilling rigs power US shale exploration

19th December 2012
Sebastião Martins

Sebastião Martins is the web editor and staff writer for Oil & Gas Technology. You can follow him on his personal Twitter account or on @OGTCavendish.

19th December 2012
Operators in US shale formations are increasingly turning to natural gas as a more cost effective and environment friendly way to fuel their drilling rigs. The resource has emerged as a substitute to more conventional ways of powering rigs, such as diesel fuel.

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. Texas-based Seneca Resources Corp last year announced it had converted two of its rigs to operate on natural gas.

In addition, the LNG arm of Canadian energy services firm Ferus was in October 2012 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 liquefied natural gas (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,” said 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.”

Data show the shift is directly tied to enhanced cost efficiency as well as reduced carbon emissions. One drill can consume up to 80 gallons of diesel an hour to run its massive electrical generators.

Using field gas to fuel one rig can save companies over USD 1m per year, and Denver based rig operator Energy Services Inc. estimates 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 emits 20 to 30 per cent less carbon dioxide, and only a small fraction of the nitrogen oxides, sulphur oxides and particulates.