Making
waves
without
water
C
arbondioxide(CO
2
)hydraulicfracturing
iscomingtotheforeasoneofthemost
effectiveandcleanestapproachesavailable
todayto increaseoilandgasproduction,evenfrom
unconventionalsourcessuchasshale,tightsands
formationsandcoalbedmethane,whilenitrogen(N
2
)
isprovinganeffectivealternativetoCO
2
inmany
situations,especiallyforfracturingshallowerwells.
Infact, it isestimatedthatuptoathirdofhydraulic
fracturingoperationsarecurrentlybeingenergised,
frequentlywithnitrogen.
When injected intogasandoilwellstheseso‑called
‘energisedsolutions’areabletoenhancehydrocarbon
productionratesandyields.Fracturingtreatments
energisedwithCO
2
orN
2
are increasinglybeing
recognisedformaximising long‑termwellproductivity,
minimisingenvironmentaldamageandreducingthe
overallcostsofresourcessuchaswater.Whenproperly
designed,energisedsolutionscan infactbemore
economicalthanwater.
SometimeswhenCO
2
ismoreexpensivethan
water, theoveralleconomicsofenergisedsolutions
aresignificantly improvedthrougha fasterpayback
andreducedwellmaintenancecost.CO
2
canbe
lesscostlythanwaterwhentheoperatortakes into
accounttotal lifecyclecostsof theirhydraulic fracture
fluidchoice.
Hydraulic fracturingandhorizontaldrilling
arechangingthenaturalgas industrybyenabling
theexploitationof reservesthatwerepreviously
inaccessible.Themostcommon formof thisprocess
usesawater‑based formulationtoachievesufficient
Figure1.
Nitrogen(N
2
)andcarbon
dioxide(CO
2
)asbulkgasesareused in
hugequantitiesfortheextractionof,
andexplorationfornaturalgaswith
inducedhydraulicfracturing.
SusanBrownlow,
LindeGasesDivision,
Germany, explains
howenergised
solutions canmake
fracturing safer and
moreefficient.
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