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ID:41232743
大小:1.80 MB
页数:12页
时间:2019-08-20
《A Guide to Shale Gas 2011》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、AnintroductiontoshalegasJune2011ShaleGasvsConventionalGasNaturalgasresourcesaretypicallydividedintotwocategories:conventionalandunconventional.Conventionalgastypicallyisfoundinreservoirswithpermeabilitiesgreaterthan1millidarcy(“mD”)andcanbeextractedviatraditional
2、techniques.Alargeproportionofthegasproducedgloballytodateisconventional,andisrelativelyeasyandinexpensivetoextract.Incontrast,unconventionalgasisfoundinreservoirswithrelativelylowpermeabilities(lessthan1mD)andhencecannotbeextractedviaconventionalmethods.Thereares
3、everaltypesofunconventionalgasresourcesthatareproducedtodaybutthethreemostcommontypesaretightgas,coalbedmethaneandshalegas.Giventhelowpermeabilityofthesereservoirs,thegasmustbedevelopedviaspecialtechniquesincludingfracturestimulation(or“fraccing”)inordertobeprodu
4、cedcommercially.ShalePlayPropertiesShalegasisnaturalgasthatisproducedfromatypeofsedimentaryrockderivedfromclasticsourcesoftenincludingmudstonesorsiltstones,whichisknownasshale.Clasticsedimentaryrocksarecomposedoffragments(clasts)ofpre-existingrocksthathavebeenero
5、ded,transported,depositedandlithified(hardened)intonewrocks.Shalescontainorganicmaterialwhichwaslaindownalongwiththerockfragments.Inareaswhereconventionalresourceplaysarelocated,shalescanbefoundintheunderlyingrockstrataandcanbethesourceofthehydrocarbonsthathavemi
6、gratedupwardsintothereservoirrock.Shalescontainorganicmatter(kerogen)whichisthesourcematerialforallhydrocarbonresources.Overtime,astherockmatures,hydrocarbonsareproducedfromthekerogen.Thesemaythenmigrate,aseitheraliquidoragas,throughexistingfissuresandfracturesin
7、therockuntiltheyreachtheearth’ssurfaceoruntiltheybecometrappedbystrataofimpermeablerock.Porousareasbeneaththese‘traps’collectthehydrocarbonsinaconventionalreservoir,frequentlyofsandstone.Thediagrambelowshowshowthegas-richshalestrataaretypicallythesourcerockforcon
8、ventionaloilandgasreservoirs.SchematicGeologyofNaturalGasResourcesSource:USEnergyInformationAdministrationShalegasresourceplaysdifferfromconventionalgasplaysin
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