Natural gas-hydrates ― A potential energy source

Naturalgas-hydrates—Apotentialenergysourceforthe21stCenturyY.F.Makogona,⁎,S.A.Holditcha,T.Y.MakogonbaDepartmentofPetroleumEngineering,TexasAandMUniversity,CollegeStation,TX77843,UnitedStatesbJSCTNK-BPManagement,P.O.Box3092,Houston,TX77079,UnitedStatesReceived10August2005;accepted3October2005AbstractNaturalgas-hydratesareanunconventionalsourceofenergy.Potentialreservesofhydratedgasareover1.5×1016m3andaredistributedallovertheearthbothonthelandandoffshore.Presently,inmanycountriesnationalprogramsexistfortheresearchandproductionofnaturalgasfromgas-hydratedeposits.Asaresultover220gashydratedepositshavebeendiscovered,morethanahundredwellsdrilled,andkilometersofhydratedcoresstudied.Propertiesofthehydratedcoreshavebeeninvestigated,effectivetoolsfortherecoveryofgasfromthehydratedepositspreparedandnewtechnologyfortheexplorationofgas-hydratefieldsdeveloped.Thecommercialproductionofnaturalgasfromgas-hydratesexistformanyyearsnowwithgoodresults.Still,manycomplexproblemshavetobestudied.Morehigh-levelstudiesonthepropertiesofthegas-hydratesareneededandnewtechnologyfortheproductionofnaturalgasfromgas-hydrateshastobedeveloped.Note,itisnottheamountofpotentialreservesofhydratedgasthatisimportant,butthevolumeofgasthatcanbecommerciallyproduced(17–20%frompotential).©2007PublishedbyElsevierB.V.Keywords:Naturalgas-hydrates;Zonehydrateformation;Development1.IntroductionThehistoryofhumanityischaracterizedbycompe-titionforthelivingspaceonoursmallplanet.Thepastcenturyhasbeenoneofhighpopulationandenergyconsumptiongrowth.Overthepasthundredyears,thepopulationonEarthgrewfour-fold,exceeding6.2bil-lion,whiletheenergyconsumptiongrewbyoveranorderofmagnitude,from0.9×109tonsofoilequivalent(TOE)to1.02×1010TOE(BP,2005).Therateofmoderncivilizationgrowthinthefuturewilldependonnumerousfactors,butthequalityandquantityofenergyusedwillbeamongthemostim-portantfactors.ThedatapresentedinFig.1reflectthedistributionandchangesofenergysourcesovertime.Currently,oilandnaturalgasaretheprimaryfuels.However,thedatainFig.2showthatthepastcenturyshouldbenamedthecenturyofbituminouscoalratherthanoilorgas.Thecumulativeroleofnuclearandhydroelectricpowerhasnotexceeded10%.AccordingtotheUnitedNations,thepotentialenergyresourcesofuraniumonearthdonotexceed4.5%oftheresourcesfromoil,gasandcoal.Fortheforeseeablefuture,oil,gasandcoalwillbetheprimarysourcesofenergy.AccordingtoBP(2005),asof1January2005,theprovenhydrocarbonreservesare161.9billiontonsofJournalofPetroleumScienceandEngineering56(2007)14–31⁎Correspondingauthor.E-mailaddress:[e-mail](Y.F.Makogon).0920-4105/$-seefrontmatter©2007PublishedbyElsevierB.V.doi:10.1016/j.petrol.2005.10.009oiland179.5trillionm3ofnaturalgas.Atthecurrentlevelofconsumption,thereservesaresufficientfor41yrforoiland66yrfornaturalgas.Thestandardoflivingofindividualcountriesinthemodernworldisdeterminedinpartbytheirlocationandspecificlevelsoftheenergyconsumption.Thequalityoflifeineachcountryisdeterminednotbythereservesoftheenergyresourcesithas,butbytheconsumptionofenergybyeachofitsinhabitants.Whilethelevelsofenergyconsumptionmayhavebeensimilarindifferentcountriesover200yrago,inthemodernworldthegapinenergyconsumptionbetweenindividualcountrieshasreachedanorderofmagnitudeormore.Forexample,althoughabout5%oftheworld'spopulationlivesintheUSA,thecountryconsumes22%oftheworld'senergyandproducesmuchoftheworld'sGDP.Atthesametime,thepopulationofIndiaaccountsforabout20%oftheworldpopulation,butitsenergyconsumptiondoesnotexceed3.2%.TheenergyconsumptionperpersonintheUSAis30timesashighasinIndia.EachinhabitantinChinauses1/10theenergyoftheircounterpartsintheUSA.Energysourcescanchangerapidly,dependingonthelevelofthedevelopmentofcivilization.Today,somecountries,includingJapanandKorea,importover98%oftheenergytheyuse.Mostoftheenergyusedthesecountriesistransportedthousandsofkilometers.However,enormouspotentialresourcesofnaturalgasresideinnaturalhydratesverynearJapanandKorea.Thesedepositsofnaturalgasingas-hydratesareactuallyfoundallovertheworldindeepwaterorintheArctic.Over220gas-hydratedeposits(GHD)havebeenfoundintheworldtodate.AmapofthediscoveredGHDisshowninFig.3(Makogonetal.,2004).Theworld'spotentialamountofnaturalgasinplaceinhydratesexceeds15quadrillionm3.Commercialpro-ductionofjust15%ofthisgaswouldprovidetheworldwithenergyfor200yratthecurrentlevelofenergyconsumption.Theproductionofnaturalgasfromhy-dratescouldbeusedtocontributenotonlytosustainedeconomicdevelopmentofindividualcountries,butalsotothepoliticalstabilityoftheworld.Fig.1.Worldenergybalance.Fig.2.Theroleofdifferentenergyinthe20thCentury,%.15Y.F.Makogonetal./JournalofPetroleumScienceandEngineering56(2007)14–31Theexistenceofnaturalgas-hydrateswasproveninthe1960s(Makogon,1965-1966).TheproblemofdevelopmentandproductionofgasfromGHDisanimportantproblemforthe21stCentury.Anumberofcountries,includingtheUSA,Russia,Japan,India,China,Koreaandothers,havenationalprogramsforstudyingandindustrialproductionofnaturalgasfromhydrates.Furthermore,inmanycountriesseriousstudiesofgas-hydratesareconductedin