OIL & GAS

What are the concerns about shalegas production and what is beingdone about it? Peter Heywoodinvestigates

42 www.tcetoday.com crpril 2012

OIL & GAS

SHALE gas. There are abundantreserves of it in North and SoutbAmerica, Europe and Asia Pacific,

particularly in China. Witb the additionof sbale gas reserves, the world's totaltecbnically recoverable natural gasresources has been increased by around40% to 22.6 xlO^b ft^ according tofigures from tbe US Energy InformationAdministration (EIA).

Furthermore, for electricity generation,shale gas has a lower CO^ output than oil socould make a major contribution to curbingglobal warming.

However a major drawback to sbaie gasis that tbe hydraulic fracturing or 'fracking'technology used in its production isregarded as a serious potential threat to theenvironment and to human health.

If shale gas is to realise its potential as asource of energy, hydraulic fracturing, wbicbwith horizontal drilling is used to createfissures in very tight shale rock to extractnatural gas, will have to be made safer. Orenvironmentally-safer alternatives will haveto be developed and widely commercialised.

Another option is for the authorities andthe gas industry to win the trust of a scepticalpublic by keeping the risks from hydraulicfiracturing well under control tbrougb closemonitoring and the introduction of bestpractices.

In tbe US where currently the vastmajority of the world's shale is producedcommercially, large sections of tbepopulation, particularly in areas of sbalegas plays or operations, lack confidencein the safety of fracking. This has triggeredcampaigns for much stricter regulationand controls combined with greatertransparency about tbe dangers of frackingchemicals.

Around 30-40% of shale gas resourcesin the US are in tbe giant Marcellus Shalewhich lies underneath the country'srelatively densely populated north easternstates.

In Europe, even before shale gas has beenproduced in commercial quantities, fi'ackinghas been banned in France and Bulgaria.

towards trustFracking systems which are either saferor are more trusted by the general publicare likely to emerge in the US, which firstdeveloped the combination of horizontaldrilling and hydraulic fracturing currentlydriving tbe shale gas boom in tbe country.

The US has by far the most experience inhandling the risks from hydraulic fracturing,in particular the creation and operation ofa regulatory and supervisory framework formanaging sbale gas production.

The first techniques used to fracture

shale rocks in the US were explosives likenitroglycerine and napalm gel. Then tbefirst hydraulic fracturing methods usingwater with gels and foams were introduced.

The 'shale gas rush' began in the US inthe late 1990s with the development ofborizontai or directional drilling wbicbenabled a drilling bit to be turned 90°several thousand feet underground. Itcan then continue to be drilled for a fewthousand feet within a sbale rock formationparallel to the ground surface.

In combination witb a new frackingtechnology, called slickwater fracturing,which employs much greater quantities ofwater with surfactants and other kinds offriction inhibitors, a series of branch-typefissures are created along the horizontalwell.

To make the fractures, water, proppants,usually comprising sand, and chemicaladditives are pumped at high pressuredown the well. Tbe pressure is then reducedso that much of tbe water, called tbeflowback, travels back to tbe surface withthe proppants or sand grains left to keep thefissures open to allow the gas to escape intotbe well.

A typical fracturing fluid would consistpredominantly of water with the chemicalingredients amounting to less tban 2%.But this is sufficient, given the number andscale of operations for large quantities ofchemicals to be used for fracking in USsbale gas production.

In addition to surfactants and frictionreducers, fracturing fluids contain solvents,scale inbibitors, gelling agents, cross linkers,corrosion inhibitors and clay stabilisers.There are also acids for removing cementand drilling mud from well casings,viscosity breakers, biocides and buffers foradjusting pH levels in the fluid.

In a typical sbale gas well tbe number ofchemicals in the fracturing fluid can varyfrom only a few to a variety with differentfunctions.

demystiiying frackingfluidsIn a minority report on bydrauMc fracturingpublisbed last year, members of the energyand commerce committee of the US Houseof Representatives said that in 2005-2009over 2,500 fracking products containingaround 750 chemicals were used by 14oil and gas service companies. Altogetherthese companies used 780m gallons ofhydraulic fracturing products.

Some of the chemicals were relativelyharmless, such as salt and citric acid, whilea few were highly unusual such as instantcoffee and walnut hulls. "Some wereextremely toxic, such as benzene and lead,"

The US has by far the mostexperience in handlingthe risks from fracking, inparticular in creating andoperating a regulatory andsupervisory frameworkfor managing shale gasproduction.

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OIL & GAS

Marcellus shale gas driiling well located inWestern Pennsyivania

A major grievance is adecision hy Congress in2005 to exempt hydraulicfracturing fluids andtheir additives from theSafe Drinking Water Act(SDWA), the main cleanwater legislation at thefederal level.

said the committee members.The most widely used was methanol,

contained in 342 fracking products, isopropylalcohol in 274, 2-butoxyethanol in 126 andethylene glycol in 119.

In an environmental impact reportissued late last year on planned shale gasproduction from the Marcellus Shale inwestern New York state, the environmentalconservation department of the state'sgovernment Usted around 350 chemicalswhich would be used or provided bysix service companies and 15 chemicalsuppliers for fracturing fluids.

Among these chemicals, the reportpinpointed several categories with 'potential adverse effects to human health.These included petroleum distillates,aromatic hydrocarbons, aldehydes, such asformaldehyde, amides like acrylamide andcertain surfactants such as 1,4-dioxane.

Among critics in the US of existing controlson shale gas production, a major grievanceis a decision by Congress in 2005 to exempthydraulic fracturing fluids and theiradditives from the Safe Drinking Water Act(SDWA), the main clean water legislation atthe federal level. The only exception is theuse of diesel fuel for fracking.

The Member of the House ofRepresentatives' Committee reported that29 chemicals in fracturing products wereknown possible human carcinogens andclassified as hazardous air pollutants underthe Clean Air Act or regulated under theSDWA, except when applied in frackingfluids. These chemicals were components of650 fracking products or around a quarter oftbe total recorded by the committee.

"The oil and gas industry should be

required to comply with the sameenvironmental safeguards as any otherindustry," Amy Mall, senior policy analystfor the National Resources Defense Council(NRDC), told a recent forum on frackingorganised by Yale University. "Right now,it's not and that's putting people andcommunities at risk." -. y

Another big complaint among anti-fracking campaigners is the way fracturing "additive producers are able to exercise theirlegal right to trade secrecy to keep details oftbeir chemicals confidential.

Under US law, trade secrecy applies toany commercial information which gives aperson "an opportunity to obtain advantageover competitors who do not know oruse it'!

The Members of the House ofRepresentatives Committee estimatedthat with 279 fracking products with oneor more chemicals, manufacturers wereclaiming a proprietary or trade secret.

In most cases in which the committeeasked for information on of theseproprietary products they were told by theshale gas companies giving evidence thatthey themselves did not have access toit because they had bought the products'off the shelf from chemical suppliers. "Inthese cases, the companies are injectingfluids containing chemicals that theythemselves cannot identify," said thecommittee members.

The New York state's envirormientalconservation department complained thatwith "a significant number" of frackingproducts it was notified about by well-service companies and chemical suppliers,it was not able to link products with specificchemicals because of the trade secrecyprotection. Consequently the state'sgovernment was unable to put togethercompound-specific toxicity data on manyfracking chemicals.

"In particular there is little meaningfulinformation one way or the other aboutthe potential impact on human healthof chronic low level exposures to manyof these chemicals as could occur if anaquifer were contaminated as a result of aspill or release that is undetected and/orunremediated," the department said.

Greater openness and transparencyamong shale gas operators and theirservices and chemical suppliers is seenby both environmental and public healthcampaigners and officials as being one wayof improving the safety of fracking.

Under the proposed regulations coveringshale gas production in New York state,well operators will be required to discloseall additive products it proposes to use,together with their material safety data

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OIL & GAS

sheets (MSDSs). This information will then berevealed to the public - except when coveredby trade secrecy rights.

Nine other US states already havemandatory disclosure rules for fracturingchemicals although the amount ofinformation required differs. Colorado is theonly state obliging companies to reveal boththe names and concentrations of chemicalswhile with others the obligation applies onlyto concentrations of hazardous materials.

Moves are being made to introducemandatory disclosure at the federal level.The Bureau of Land Management proposedearlier this year a disclose requirement forfracturing chemicals on federal land for whichit is responsible.

In response to a petition by 120environmental and public health groups, theEPA announced last November that it wouldbe "initiating a proposed rulemaking process"for obtaining data on fracking chemicalsunder the Toxic Substances Control Act(TSCA). This could require data to be revealedon adverse health and environmental effectsand from health and safety studies.

Driii rig set up for winter driiling in Wyoming

safer and greener?The EPA is already conducting a US$12mstudy, due to be completed in late 2014, onhydraufic fracturing and its potential impacton drinking water resources.

In addition to greater transparency, safetycould be enhanced by shale gas operatorsmaking greater use of green chemicals.

Leading ou and gas services companieslike Halliburton and Schlumberger havedeveloped hydraulic fracturing products tomeet the strict environmental protectionrequirements of offshore fracking activitiesin areas like the North Sea.

Halliburton also markets a CleanStimfracturing fluid formulation for onshorehydraulic fracturing. This is made fromingredients sourced from the food industrythough it warns that the fluid should notbe considered to be edible. Chemicalcompanies like Dow Chemical also marketenvironmentally friendly fracturingsurfactants.

One drawback of the few green chemicalformulations that are available is that theycan be effective only in certain conditions.Some, for example, cannot be used in earthwith a high clay content.

In its recommended new regulationson shale gas production. New York state'senvironmental conservation department isproposing that applicants seeking shale gasproduction permits will have to evaluateand, where possible, use alternativechemicals which pose less risk to theenvironment.

Critics have pointed out that it will bedifficult to evaluate alternatives properlywhen there is a lack of information about thechemicals in the fracturing chemicals theywould be replacing.

A long-term option is for the applicationof fracturing systems which rely on little orno water and would generally as a result beusing much fewer chemicals. Some of thesewere being developed before slickwaterfracturing became the prevalent technology.

They include the uses of liquid CO^and nitrogen gas with foam, with eachcontaining proppant mixtures. The CO^vaporises and in the case of nitrogenmingles with the shale gas, leaving only theproppant in the fractures.

In a similar technology propane orliquefied petroleum gas, which mostlycomprises propane, is used to carry theproppant but with a gel which has theadvantage of having a higher viscosity.Furthermore it does not damage thefracture, which is a problem with the othertwo.

Propane or LPG fracking technology iscurrently only being provided by a singleCanadian company, Gasfrac, which has

been tending to limit its operations toCanada. In the US it has not yet gainedpatent protection. A major difficulty is thatthe technology is unlikely to be widelyappfied in shale gas plays without a propanesupply infrastructure which could requirepipelines, according to analysts.

Even if alternative technologies tohydraufic firacturing are successfullydeveloped for viddespread use, it looks likelythat key to improvements to the safety ofshale gas production and above all its publicimage will be more effective regulationsand management systems through theintroduction of agreed best practices.

In a recent report on natural gas, theMassachusetts Institute of Technology(MIT) highfighted the absence of majorsafety incidents in the US shale gas sector."With over 20,000 shale wells drilled in thelast ten years, the environmental record ofshale gas development has for the most partbeen a good one," it said. But it warned thatdue to the damage that could be causedby one major incident, the industry mustcontinuously strive to mitigate risk andaddress public concerns.

The EPA has indicated that the future fieswith an efficient integration of regulationand monitoring at the federal and statelevels, through the network of oil and gas andwater management authorities run by stategovernments. Some of these local agencieshave been active since the first oil and gas,including shale gas, was produced in the19th century.

Some experts reckon that the avoidanceof serious incidents of drinking watercontamination by fracking processes hasbeen mainly due to gradual advances in stateregulations and controls. "What we needis not more stringent regulations but moreappropriate regulations - and these canbest be set at the state level by collaborationwith stakeholders and industry," says DavidBurnett, director of technology at Texas A&MUniversity's Global Petroleum ResearchInstitute, at the Yale University forum.

The decentraUsed regulatory model beingapplied in the US may be followed by theEuropean Union, where there are relativelylarge shale gas reserves.

A recent consultancy report for theEuropean Commission earlier this yearconcluded that existing EU and nationallegislation was adequate to deal with shalegas operations but that there should beflexibility for member states to exercisecontrols on a case-by-case basis. With shalegas, safety is increasingly being seen to bedependent on the actions of local rather thancentral authorities, t ee

Peter Heywood is a freelance journalist

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