26/11/2015 Dual­fuel systems power up ­ Drilling Contractor

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The first Halliburton dual­fuel Q­10 pump wasscheduled to be run in Colorado this summer.The pump is part of the company’s Frac of theFuture, designed to reduce wellsite footprint,improve environmental performance and

enhance reliability.

Dual­fuel systems power upin 2013, Drilling Rigs & Automation, Features, September/October Sep 10, 2013 2 Comments

Market for technologies to fuel drilling, wellstimulation operations with natural gasexpanding rapidlyBy Katherine Scott, associate editor

Technology that seamlessly switches betweendiesel and natural gas– most call it dual fuel – isfinally hitting its stride. Making an impact in bothdrilling and fracturing operations, dual­fuelsystems have been estimated to save operatorshundreds of thousands of dollars a year whileoffering them a choice in the fuel they use,whether its LNG, CNG, field gas or, when naturalgas supply isn’t readily available, diesel; to many,it’s a win­win.

“It’s about the optionality. The magic about thesedual­fuel kits is that you can run it on diesel, but it can run on a mix if it’s available at thetime,” Alexander Robart, a principal withPacWest Consulting Partners, a strategy consultancy andmarket intelligence firm, said.

Simply stated, dual­fuel involves the ability to run engines on a combination of diesel and natural gas,allowing companies the flexibility to choose which fuel to use based on cost, supply and operation.Within the oil and gas industry, the use of dual fuel so far has mostly been limited to onshore NorthAmerica in drilling rig and frac pump applications. PacWest estimates that more than 100 drilling rigs inthe region now have dual­fuel capabilities. “We estimate that natural gas for frac/drilling operations isresulting in the use of about 8 bcf/year of natural gas. Most of it is being consumed for drilling,” JamesCoan, consultant with PacWest said. In its 2013 Annual Energy Outlook, the US Energy InformationAdministration estimated that the total natural gas consumption in the US in 2011 was 24.4 tcf.

While drilling technologies using dual fuel have been under continuous albeit slow development sincethe first application in 2006, this year it’s been all about fracturing operations, Mr Robart said.Describing it as being in an “experimental stage,” he said 2013 is the first year to really come on thescene in the context of fracturing. “But now everyone is testing it out in fracturing operations for the firsttime to see what their experiences are and then figure out what to do with it from there.”

Compared with drilling, fracturing operations require significantly more power, and it can be a challengeensuring a consistent and quality supply of natural gas for such applications. “Frac spreads are anywherefrom 16,000 to 24,000 horsepower or even higher, so that horsepower demand requires a significantlylarger amount of natural gas supply,” Karl Blanchard, VP of Halliburtonsaid. “There’s a big difference

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Caterpillar announced lastyear a commitment to go“all­in” on natural gas andmanufacture more natural

gas equipment andengines. Part of the

initiative is its dynamicgas blending (DGB) kit forwell stimulation, includingfracturing applications,launched at the 2013Offshore Technology

Conference. Using naturalgas to fuel fracturing

equipment has taken offrapidly this year, drivingexpansion in the overall

dual­fuel market.

in being able to manage and deliver that much.”

This growth in dual­fuel fracturing is driving strong growth overall indual­fuel technologies, Ed Wolf, sales manager for Iowa­basedAmerican Power Group, said. His company has doubled thenumber of fracturing units they’ve equipped with dual fuel since lastyear. “The drilling sector has been strong for quite a few years, but justin the last year the fracturing industry has really come on board. There’ssome rumors that the fracturing industry is going to be using more dualfuel than the drilling rigs eventually.”

Like most new technologies trying to make a meaningful impact in theoilfield, the use of dual­fuel technologies comes down to cost. “Rightnow we’re just not in the booming market we were in before, so peopleare thinking, ‘how can I reduce costs across the board?’ It’s thequestion of who is going to drive it by spending the money and thenhow they are going to share those savings,” Mr Robart said. “It’s notgoing to be one group that makes the decision; it needs to be madetogether to push this forward. There are a lot of complex pieces here tobuild the capacity and create the demand.”

Cost pressures have increased over the past year and half, he said,particularly in gas plays like the Marcellus. “The gas plays is wheredual fuel makes the most sense because you’ve got readily availablegas,” he said, adding that dual­fuel kits can range from $60,000 to$100,000, with an additional $20,000 required for installation. If thesekits can enable cost savings beyond the initial investments and boostproject margins, “that makes perfect sense.” Typically, a rig utilizes three engines that each requires itsown conversion kit.

Another important factor in the cost saving equation is the type of natural gas that can be used in a dual­fuel operation. “The long­range goal that most people have is to work toward being able to useconditioned field gas. It’s abundant. It’s relatively cost effective. It’s environmentally positive,” MrBlanchard said.

Mr Coan agreed, noting that savings of nearly 2.5% to 5% of the total well cost could be achieved byusing field gas, assuming a substitution rate of 50% and that diesel for fracturing operations accountedfor 5% to 10% of total well costs.

Dual­fuel technology

At the 2012 Natural Gas for High Horsepower Applications Summit, held 26­28 September inHouston, Caterpillarannounced its intentions to invest heavily in natural gas and to manufacture morenatural gas­fueled equipment and engines.Joel Feucht, the company’s director of gas engine strategy forenergy & power systems, stated at the summit, “We have decided to go all­in on gas. We are going toinvest because we see a long­term, global opportunity. Large engines are going gas. It’s not debatable;

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Caterpillar’s first drilling DGBunit was shipped to Russia inDecember 2012. Fuel savingspossible with the system dependon multiple variables, includingthe application, the quality of the

gas and available volume.

it’s our conclusion.”

Two components of the company’s “all­gas” initiative are itsDynamic Gas Blending (DGB) kits, one for drilling that waslaunched in May 2012 and one for well stimulation, includingfracturing applications, launched at the 2013 OffshoreTechnology Conference. Both operate under the goal ofdisplacing as much diesel as possible with natural gas, which caninclude blends with ethane and propane, while maintaining theengine’s power and transient capability, according to thecompany.

Most dual­fuel projects so far have involved retrofits of currentequipment “because of the large diesel­only engine populationalready in the field today and the relative ease of the retrofit procedure,” Russ Goss, a Caterpillar projectmanager in the Global Petroleum group, said. The kits can be installed in the field in approximately threedays.

“The fuel savings achieved with this system depends on a number of variables, including the application,the quality of the gas, the pressure and available volume,” Mr Goss added. “But by retrofitting existinggenerator sets with this technology, a typical drill rig operator can save as much as $400,000 in one year,based on DGB’s substitution capabilities on a typical three­engine drilling rig with engines seeing around4,000 hours per year. It’s also based on average fuel costs of around $3.50/gal diesel and $4/MMBTUfield gas, along with assuming gas availability 70% of the time.”

Caterpillar currently has multiple drilling rigs and frac spreads operating in the US, Canada– in thePiceance basin, Marcellus, Barnett, and Haynesville – and is operating kits in production applications inRussia.

On the frac side, requirements are different because frac engines must run at variable speeds, as opposedto a constant speed for drilling, Scott Roberts, Caterpillar well service product marketing manager forthe marine and petroleum power division, said. The DGB kit for fracturing, which is certified to Tier 2emissions, has a maximum substitution rate of just over 60% at 100% load. “Our system can detect thechanges in the fuel quality and adjust itself without someone having to go fix settings or recalibrateanything,” he added.

Both the drilling and well stimulation kits can run off a variety of natural gas ranging from 800 Btu to2,300 Btu; pipeline­quality gas is 1,200 Btu, and field gas in the Bakken averages 1,500 Btu,ToddKrueckeberg, North America sales & service manager for global petroleum for Caterpillar, said. “Youhave to distinguish between pipeline quality, which is almost like LNG and CNG, and then literally whatcomes out of the wellhead. The raw gas at the wellhead is where you get the money savings.”

Field implementation

Although it may be operators who ultimately drive the adoption of dual­fuel technologies, particularly inwell stimulation applications, it’s clear that drilling contractors also have a significant role to play.Engines on existing rigs can be retrofitted with dual­fuel kits, and newbuild rigs can be equipped with

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Scandrill’s Scan Endeavor isusing this prototype gas­

conditioning skid from Pro­GasServices. The contractor is

running five SCR rigs with dual­fuel systems – four in the

Marcellus and one in the EagleFord.

Precision Drilling’s Rig 828,working in Colorado, is amongfour dual­fuel rigs the companyhas operating in the US. An

additional eight are working inCanada.

dual­fuel engines from the outset.

Scandrill, which installed its first dual­fuel retrofit in late 2012, isrunning five SCR rigs with dual­fuel systems – four in theCarthage, Panola county area and one in the Bryan­CollegeStation area. “Dual­fuel systems are here to stay,” Paul Mosvold,vice president of Scandrill, said. “We continue to look at ways ofoffering the most effective and efficient rig combination to ourcustomers, and one of the ways of doing that is integrating thedual­fuel system in any newbuilds in the future.” Most rigs withdual­fuel systems also have rig­walking systems, which allowthem to stay on a single location for months at a time. Thisallows for greater economics of scale when installing gas supplylines to the rig.

Scandrill and Anadarko agreed to participate in a 2011 field­testing program for Caterpillar’s drilling DGB kit. “We have operated two Caterpillar DGB systemssuccessfully on our Scan Endeavor rig and recently installed the system on the third rig engine. We havealso chosen to install four American Power Group (APG) systems on four additional rigs.” All areoperating on field gas, and Mr Mosvold said his company has seen substitution rates in the mid­60%range with Caterpillar’s system and mid­40% on the APG system.

“In the areas we operate, field gas or pipeline gas has been in most cases readily available, but earlyplanning when building locations and sourcing of gas will help make the dual­fuel transition a successfor both operator and contractor,” he continued.

Precision Drilling also says it has seen a steady increase inoperator interest in dual­fuel systems, Darcy Whitten, thecompany’s manager of engines, said. The company currently hasfour dual­fuel rigs in the US – two each with Noble Energy andwith Southwestern Energy – and eight in Canada working forEnCana. “Within typically 10 months, depending on what typeof fuel they’re using, you can see your rewards start to pay off. Iknow a lot of contractors are hoping that they’ll have 10 to 20dual­fuel rigs in the next year or so,” Mr Whitten said.

He added that operators have been willing to pay for the retrofitsthrough higher rig rates. “The dayrate of the rig increases until the total cost of the system is recovered,then the dayrate returns to the original amount,” he explained of Precision’s dual­fuel rigs.

Mr Whitten also noted that he has seen no impact on engine life with dual­fuel systems so far. “We ran adual­fuel system on a rig for 10,000 hours and stripped the top end (of the engine) off and checked forany signs of wear, and there was absolutely nothing. That engine has no idea that you’re putting naturalgas into it.” Precision Drilling installed its first dual­fuel system on Rig 520 in 2008 for EnCana andcontinues to use the same dual­fuel kit today, Mr Whitten said.

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An Altronic displaypanel for the bi­fuel kiton a Precision Drillingrig confirms the systemis operating. GSP1 isincoming gas pressure,MAP1 is the manifoldabsolute pressure(engine manifold

pressure), and MAT1 isthe manifold absolutetemperature (engine

manifold temperature).

An LNG supply truck is tied intothe rig supply line for a Precision

Drilling dual­fuel rig.

The company is now even going a step beyond dual fuel by retrofitting tworigs with 100% natural gas Waukesha engines. The rigs are workingfor Antero Resources in the West Virginia/Marcellus Shale and Ohio/UticaShale area. “Obviously that’s part of how the market is driven, but as apower systems manager, it’s better for me to just put the dual­fuel systemon, and I can use it or not use it.”

For contractors who prefer to enter the dual­fuel market with built­intechnology rather than retrofits, China­based Honghua Group and its USsubsidiary Honghua America are developing a next­generation onshore rigfor shale drilling that will come equipped with dual­fuel engines. Aprototype for the rig is under construction at the company’s Houston yardand scheduled for completion in late 2013 or early 2014. “Dual­fuelengines, or more specifically mixed­fuel engines, have been maturing inthe European and United States markets for the past 15 years and is onlynow more widely used, not only in applications of power rigs but alsofracturing engines,” Zhang Mi, chairman and president of HonghuaGroup, said.

In China, too, he sees a growing prevalence in dual fuel, particularly for unconventional oil and gasexploration. “The trend of dual­fuel systems being adopted throughout North America and othercountries is already quite noticeable, but in China a few companies, such as PetroChina XinjiangOilfield, have also begun pilot programs. Future demand will be quite large, especially in America, ascompanies are beginning to develop processes to purify the unpurified gas that is expelled from wells.”Better processes for conditioning field gas will expand dual­fuel applications for the future, he said.

Dual­fuel fracturing

Looking beyond the scope of drilling, service companies havecontinued to develop a number of products implementing dual­fuel technologies.

With the increasing activity in shale plays, Halliburton has seen asignificant increase in the amount of equipment at wellsites. “Ourenvironmental footprint, business footprint and the human capitalat a typical location are the largest they’ve ever been. Werecognize that as an opportunity to make a step­change in ourequipment suite,” Ivan Blanco, program manager atHalliburton’s Duncan Technology Center, said.

The company is developing a suite of tools called Frac of the Future, designed to reduce wellsitefootprint, improve environmental performance and enhance onsite equipment reliability. Components ofthe suite include technologies to reduce bacteria in fracturing fluids, recycle flowback and producedwater and utilize solar power for proppant storage. There’s also the Q10, a dual­fuel fracturing pumpwhere natural gas enters a gas train and is then filtrated and metered to sub out diesel. “This 2,000­hpunit running on diesel alone can burn 100 gallons an hour at full load. We’re able to substitute a max of

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A top view of HonghuaAmerica’s newly designed

1,500­hp fast­moving land rigwith automatic drill floor

equipment. The rig, which isscheduled for completion latethis year or early next year, willcome equipped with dual­fuel

engines.

60% of that diesel with natural gas at full load, whether it’s CNG, LNG or conditioned field gas.”

The company has been working with Apache and Caterpillar since January 2012 to develop dual­fueltechnologies for pumping equipment and just commercialized it in January of this year with 12 pumps at24,000 hp.

Halliburton started the dual­fuel pilot with Apache in October 2012 in the Granite Wash and was able torun an entire frac spread with 12 Q10 dual­fuel pumps by January, Halliburton’s VP Mr Blanchard said.“We substituted north of 50% of the fuel demand with natural gas.” This spread is still running and hascompleted over 35 jobs for Apache.

Within Halliburton’s own operations, the company also is switching to natural gas when possible. InMay the company deployed approximately 100 light­duty bi­fuel trucks across several US fieldlocations. Bi­fuel in this case means the vehicle runs on natural gas until the tank runs out, then theengines and controls automatically switch to a reserve tank of gasoline.

Under this US pilot program, the bi­fuel trucks will eventually be assigned to 15 locations across sevenstates – Texas, Oklahoma, Colorado, California, Louisiana, Utah and Pennsylvania. “We selected theselocations based on existing public CNG infrastructure, so the hope is that, as the demand grows, theinfrastructure will follow. Once we gather the information from the pilot program, we’ll look at how wecan make a larger­scale adoption globally,” Mr Blanchard said.

Pioneer Energy Servicesis another company that is testingCNG­powered vehicles with three Chevrolet 2500HD 4X4Extended Cabs that have been converted to run on both gasolineand CNG using an AutoGas America system. The truck startswith a gasoline engine but then switches automatically to run onCNG. When the CNG runs out, the engine switches back to runon gasoline. “CNG was the fuel of choice for powering light­duty vehicles at Pioneer because of its reliability and growingavailability as a transportation fuel,” Daniel Hindes, wellservicing district manager for Pioneer, said. The company isconverting its existing pickups for $8,500 to $10,000 dependingon the engine and CNG tank size.

He added that the decision to test the new trucks was drivenprimarily by cost considerations. “We have paid CNG prices of$1.08 up to $2.24 of gas­gallon equivalent. The mileage is the same when running on CNG, so thecomparison is simple math. When CNG is $1.99 per gas­gallon equivalent and gasoline is $3.50 pergallon, we are saving $1.51 per gallon. We expect to recoup the additional cost for the CNG conversionwithin 24 months depending on how much the driver can operate the vehicle on CNG.”

Although the company doesn’t plan to convert more existing trucks beyond the three they have now, itis evaluating CNG bi­fuel as an option on any vehicles purchased new. “The economics of converting anexisting pickup are highly sensitive to the age and mileage of the truck. With today’s conversion prices,you need a pickup with low mileage to justify the expense of conversion over the life of the

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Hythane Company’s OptiBlendretrofit technology for dieselgenerator sets can achieve

between 50% to approximately70% substitution rates.

pickup,” Daniel Hindes, Pioneer’s well servicing district manager, said. “The option when ordering CNGthrough the dealer for 2013 is $11,000.”

One of the three trucks is being driven by management and sales staff for frequent trips to and from aPioneer office in Bryan, Texas, and the Houston area. The other two are being used in daily operations toand from wellsites. “We are recording mileage information and figuring up the cost difference betweenrunning on CNG and running on gasoline… As we replace our existing fleet, we will definitely considerCNG bi­fuel vehicles for the locations that have CNG available,” Mr Hindes said.

Houston has six commercial CNG filling stations around the city, and others are located in Conroe,Bryan, Katy and Beaumont. Still, Mr Hindes acknowledged that CNG availability remains low, and thishas significantly impacted the project. “Our tests have shown the economics of the expense for theconversion are highly sensitive to the percentage of the time that you can run the vehicle on CNG versusgasoline. We are shooting to run our pickups in Bryan on CNG 80% of the time. If we can run ourpickups 80% of the time on CNG, the economics are very attractive.”

Pioneer is also researching options to convert well­servicing rigsand pumps to run on CNG and is testing the fuel­blending kitsfor engines on its drilling rigs. The company has installed theCaterpillar DGB kits on two of its drilling rigs and is in the veryearly stages of use.

Hythane Company, an alternative fuel company dealing withvarious engine combustion technologies, in 2011 commerciallylaunched the OptiBlend retrofit technology for diesel generatorsets. The technology can burn a mixture of up to 70% natural gasand 30% diesel fuel, but John Nadeau, the company’s directorof sales, marketing, & business development, contends that it’sall about performance. “Nobody would be using this technologyif it weren’t for its performance…If the operators had to give something up in order to get this, itwouldn’t be nearly as appealing.”

Mr Nadeau explained that the system injects natural gas, whether it’s pipeline gas, vaporized LNG orwellhead gas, into the air intake stream of the engine. “It goes into the combustion chamber and createsadditional combustion, and the OEM control system reacts by adding less diesel to the mixture.” Theamount of gas injected is based on several engine output parameters, such as engine vibration, exhausttemperature, generator frequency, and generator load via a PLC unit. “It’s a continuous feedback loop sowe’re constantly adjusting the amount of gas going into the engine.”

Another system that monitors the engine to constantly adjust the amount of natural gas to feed in is theTurbocharged Natural Gas electrical control unit (ECU) from AGP. “Our ECU lets us determine howmuch gas substitution we need and when to use it,” APG sales manager Mr Wolf said. “We use avariable throttle body to determine the gas amounts at each of those different loads, and it reacts inmilliseconds as the engine moves the loads back and forth.”

Depending on the engine and operation, Mr Wolf said, substitution rates with APG’s kit range from 30%

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David Knapp, district managerfor FTSI in Williamsport, Pa.,inspects one of the company’s

dual­fuel pressure­pumping unitsin the Marcellus Shale in

northeastern Pennsylvania. FTSIpartnered with Cabot Oil & Gas

this year to test dual­fueltechnology on its pressure­

pumping equipment.

FTSI employees PeterBallard and ChrisHightower work onthe field test of one ofthe company’s dual­

fuel pressure­pumping units in the

at 10% load to 50% to 60% at 75% load. He noted, however, thatcompanies should aim for an overall average substitution rate inthe 50% to 60% range because running substitution at 70% orabove could cause heat problems with the engines, and thiscould reduce equipment longevity. “We feel the safe way is inthe 50% to 60% for substitution for longevity of the engine andactually an increase in its longevity because it burns cleaner.”

Last summer during a drilling application in Oklahoma, a dual­fuel rig with three 3512 Cat engines was used to drill a horizontalwell. Over the course of the 78­day run, a total of 91,000 gallonsof diesel and 102,000 diesel­gallons equivalent of natural gaswere used. “The difference in the cost between diesel and naturalgas was $3 a gallon, so it saved $306,000,” Mr Wolf said.Average substitution was between 50% and 55%.

In May, FTS International (FTSI) partnered with Cabot Oil &Gasto field­test a dual­fuel technology on pressure­pumping equipment for a fracturing operation innortheastern Pennsylvania. The aim was to use only gas from a producing gas well. “CNG or LNG couldbe used, but these do not provide as much opportunity to improve efficiency and reduce truck traffic tothe wellsite as with using field gas,” Shawn Stroman, VP of engineering for FTSI, said. The unit tested atthe Cabot site provided an approximately 63% substitution rate, according to the company.

The Marcellus is an especially good basin in which to test dual­fuel technology, Kevin Krebs, FTSIsenior VP of manufacturing, said, because “wells produce a very ‘dry’ methane gas, which is veryengine­friendly and doesn’t require additional refining to be used to power our pumps. The only stepbetween the pipeline from the well and the engine is a gas­processing unit that reduces gas pressure fromthe well pipeline. In other parts of the country where the natural gas is not as engine­ready, additionalprocesses must be put in place to prepare the gas for use in the engines.”

In order to operate using natural gas during the Pennsylvania field test,FTSI’s mobile pressure­pumping unit at the site was retrofitted withCaterpillar’s DGB kit. However, Mr Krebs expects that enginemanufacturers will soon begin selling engines built as duel fuel from the get­go. “The main advantage to purchasing a dual­fuel engine, as opposed toconverting an existing engine, is the economy that results from the enginebeing built with all the parts required for dual fuel already in place. With aconversion situation, some existing parts must be replaced with parts suitedfor dual fuel.”

Specializing in natural gas dedicated engines

Like Precision Drilling, other companies are also moving beyond dual fueltoward entirely natural gas­reliant products. Noble Energy, for example,kicked off a pilot program in 2011 in the DJ Basin to compare the benefitsof diesel versus natural gas. The program gathered 12 months of operating

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Marcellus Shale.FTSI’s pressure­

pumping equipmentwas retrofitted withCaterpillar’s DGB kit

for the test.

Ensign Energy Services’ Rig 124operates on the Jonah Field inWyoming using field gas withdedicated spark ignition lean­

burn engines.

data on three land rigs – two LNG­dedicated rigs and one running solely ondiesel. The purpose was to demonstrate the operational and economicviability of powering the majority of Noble’s rigs with LNG, Bryant Dear,drilling engineer­DJ Basin for Noble Energy, said at the 2013 IADC DrillingOnshore Conference in Houston earlier this year.

As of May, Noble was operating one LNG­dedicated rig and four dual­fuelrigs. Each of the dual­fuel rigs is equipped with a GTI Altronic bi­fuel kit set up on three Caterpillarengines, Mr Dear said. “It’s too early to tell what our (fuel substitution) rates are, but we’re working toincrease those as technology gets better and these systems get better… One thing we do know is you’vegot to displace as much diesel as possible (to achieve maximum cost savings).”

To support this extra demand for LNG, which Noble decided was the best natural gas option due to itshigher energy density and consistent quality, the operator is even building an LNG plant in WeldCounty, Colo. “That’s going to bring our price much further down,” Sean Howley, senior businessanalyst for Noble Energy, said. Noble plans to build a portfolio of LNG­dedicated and dual­fuel rigs andis expanding LNG applications to its frac fleet as well. At the time of his presentation, Mr Howley saidNoble had one dual­fuel frac engine that was running on LNG in the DJ Basin and expected to start asecond in June. “If we don’t need (the LNG) on a frac job, we can roll it over to one of our rigs. Whenwe don’t need it on the rig, we can roll it over to a frac job. It provides some really nice synergies forus.”

At Ensign Energy Services, engineering manager BrianMurphysaid the company has seen an upswing in interest fromoperators in using natural gas as fuel, including 100% naturalgas­dedicated rigs. The company first partnered withoperatorEnCana to use a natural gas­dedicated engine in 2006 inWyoming’s Jonah field. The reduced emissions footprint allowedthe field to be developed more rapidly, he said.

Today, out of Ensign’s 300+ drilling rigs, 17 run solely onnatural gas and three are dual fuel. The most recent addition wasa 100% natural gas­dedicated rig that headed to California for amajor operator in late August. “With a dedicated natural gasengine, we believe that we can save in excess of $1 million ayear on fuel. With dual fuel, you’ll save around $200,000 to $300,000 a year.” If the field gas supply isexpected to be intermittent, dual fuel would make sense. Otherwise, if you’re operating in a field that hasthe infrastructure and the reliability of quality field gas, “that’s the first place where you want to applydedicated natural gas engines; it’s the biggest bang for the buck,” Mr Murphy said.

In terms of performance, he added that he’s not seen much difference between the two types of engines.“A diesel engine operates on compression. It compresses the fuel, squeezes it, causing the fuel to igniteand then you generate power,” he explained. With natural gas engines, there are lean­burn and rich­burnversions, but in both an electrical spark ignites the fuel. “Rich burn engines are more diesel­like inperformance,” he said, but they are also much heavier than lean­burn engines and require extra emissioncontrol features.” A lean­burn engine refers to a higher air­fuel ratio, whereas a rich­burn has a balanced

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GE’s recently EPA mobile­certified VHP natural gasengine allows operators tomove the engine to any

location in the 49 states asthe emissions are already

approved.

air­fuel ratio.

In July, two of GE’s Waukesha natural gas­powered engines – VHPL5794GSI and VHP L7044GSI – received EPA certification formobile application in non­road use,Aaron Trexler, power generationproduct line director for GE’s Waukesha gas engines, said. “With ourrich­burn combustion technology, drill rig operators can power theirsite on almost any field gas, pipeline gas, propane gas, or CNG andLNG. The emissions are already approved by the EPA, so anylocation in 49 states these engines can be moved and operated.”

The two engine models, which meet the EPA non­road mobile Tier 2emissions requirements, produce up to 95% less emissions comparedwith a diesel engine in terms of NOx and carbon monoxide, andthere’s very little particulate matter, he said. A key differentiating feature is the engine’s ability to run onfuel in the 950 to 1,650 BTU range and accepting large load changes from the rig operation withoutinterruptions to the power supply. “I think it’s going to get to a point where the driller’s not really goingto know a difference other than they’re going to be saving money and having less emissions.”

Looking to the future, Mr Trexler said the rapid growth of LNG infrastructure in North America ischanging the game in terms of widespread LNG adoption. “Even in the last six months, the LNG build­out infrastructure is moving at a very quick pace to meet the challenges of getting gas to sites that maybedon’t have much field gas or maybe supply is a little uncertain at times,” he explained. “Just talking tosome of the contractors and the producers, they’re able to write contracts this year for LNG supply wherelast year it wasn’t even on the table.”

PacWest’s Mr Coan stated that four oil and gascompanies are investing in the expansion of LNGfacilities in North America for upstream anddownstream needs. “Most of the LNG currentlyconsumed comes from existing small­scale plants thatutilities built long ago to store natural gas foremergency situations.”Shell is planning to build atleast two small­scale LNG facilities in Geismar, La.,and Sarnia, Ontario, each with a production capacityof 250,000 gallons/year. Stabilis intends to build fivefacilities, each capable of producing 100,000 to250,000 gallons of LNG per day, and Noble Energy is constructing a facility in Keota, Colo., withproduction capacity for 100,000 gallons of LNG per day. ConocoPhillips has announced that it is alsoplanning a facility but additional details are not available yet.

PacWest’s Mr Robart added that there’s a range of different industries like locomotives or wastemanagement that are increasingly experimenting with natural gas. “I do firmly believe that thisrepresents a tip­of­the­spear initiative to convert over to natural gas. The oil and gas industry represents areally meaningful early­stage set of investments to start converting things over, and I think there will bean overflow for this investment to drive natural gas demand across other related sectors.”

26/11/2015 Dual­fuel systems power up ­ Drilling Contractor

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