高韧性油井固井材料的性能与应用

(210009)HD[H()w=5.5%Dw=0.2%]HDHD198%222%Young38%40%HD(w=5.7%)USZ(w=0.2%)F17B(w=1.2%)F17A(w=3%)TE256.1A0454–5648(2007)–0786–05PROPERTIESANDAPPLICATIONOFHIGHTOUGHNESSOIL-WELLCEMENTINGMATERIALHUASudongYAOXiao(CollegeofMaterialsScienceandEngineering,NanjngUniversityofTechnology,Nanjing210009,China)Abstract:Damageoffragilecementsheath,inducedbyperforationandstimulationtreatments,cancauseformationfluidtocrossflowandincreasethedamagetothecasing.Anoveltougheningagent,namedHD,tosolvethisproblemisintroduced.TheHDcon-sistsofsynthesizedrubberparticlesnamedH(w=5.5%,wismassfraction,thesamebelow)andspecialchemicalfibersnamedD(w=0.2%).Itseffectsonthemechanicalpropertiesandthemicrostructureofsetcement,theengineeringpropertiesofslurryandthecompatibilitywithotheradmixtureswereevaluated.TheexperimentalresultsshowthatboththetoughnessandtheelasticityofsetcementwithHDareincreasedmarkedly.Theimpactworkisincreasedby198%222%andtheYoung'smodulusisdecreasedby38%40%.ThecomprehensiveengineeringpropertiesoftheslurrywithHD(w=5.7%),dragreducerUSZ(w=0.2%),filtratelossadditiveF17B(w=1.2%),andcrystalloidexpandingagentF17A(w=3%)meetsthetechnicalrequirementsforcementingoperations.Aftercalculatingtherateofthespreadingofstresswavesandsimulatingtheperforation,itisfoundthattheincreaseoftheelasticityofsetcementcouldhelptoincreasethetoughness.Keywords:oil-wellcement;toughness;impactwork;fibercontent;cementingCementingisaprocessinwhichslurryisplacedintoanannulusbetweencasingandformationtoisolateproducibleformationhorizonsandsupportcasing.[1]Cementisoneofthemostimportantcementingmaterials,butsetcementhasinherentfrangibility.Duringthede-velopmentofoil-wells,thecementsheathisexposedtohighenergyconvergenceoftheperforatingcharge,whichbrings3000MPato4000MPaimpactpressure.[2]Thecementsheathwillcrackiftheradialtensilestressexceedsitslimit.Thecracksinthecementsheathmaybeextendedwithfurtherwellstimulations,evenleadingtothetotalfailureoftheisolationandcausingtheformationfluidtocrossflow.Duringtheproductionofoil-wells,thecasingmayexpandradiallyandaxiallybecauseofhighpressureandhightemperatureresultingfromhydraulicfracturingtreatments,highdrawdownpressuresandsteaminjection.Theexpansionstresscausesthecementsheathtocrack,orcausesthebondinterfacebetweentheoutsidesurfaceofthecementsheathandformationtofail.Thebondin-2006–08–032007–02–03863(2003AA327120)(BSCX200503)(1981)(1960)Receiveddate:2006–08–03.Approveddate:2007–02–03.Firstauthor:HUASudong(1981),male,postgraduatestudentfordoctordegree.E-mail:[e-mail]:YAOXiao(1960),male,professor.E-mail:[e-mail]35620076JOURNALOFTHECHINESECERAMICSOCIETYVol.35No.6June2007·787·356terfaceisnamedthesecondaryinterface.Ifthecementsheathfracturesorthebondinterfacefails,therateofthecasingdamagewillbeincreasedbecauseofseverecorro-sionofthecasing,andtheoutputofoil-wellswillbere-ducedremarkably.Additionally,thetoughnessofthece-mentsheathneedstobeimprovedfurther,duetothein-creasednumberofintricatewells,suchashorizontalwells,inclinedwellsandthermalproductionwells.Ausualmeasuretoimprovethetoughnessofce-mentsheathisusingafiber-tougheningagent.However,manyoverseasanddomesticstudies[3–8]haveshownthatthetoughnessofthesetcementwithordinaryfi-ber-tougheningagentisincreased,buttheYoung'smodulusisscarcelydecreasedandtheelasticityishardlyimproved.Infact,astheYoung'smodulusisdecreased,therateofthespreadingofstresswavesproducedbyperforationinthecementsheathisdecreased.Becausetherateofstresswavespreadinthecementsheathisde-creased,thefragiledamageofthecementsheathisde-creased.Therefore,itisnecessarytodevelopanovelagentthatisabletoimproveboththeelasticityandthetoughnessofsetcement,butdoesnotaffecttheengi-neeringpropertiesoftheslurry.Theinfluencesofsynthesizedrubberparticles(H),specialchemicalfibers(D)andnoveltougheningagent(HD)onthemechanicalpropertiesofsetcementwerestudied.TheeffectoftheHDontheengineeringproper-tiesofslurries,andthecompatibilityoftheHDwithce-mentandotheradmixtureswereinvestigated.Thefunc-tionalmechanismoftheHDwasdiscussed.1Experiment1.1MaterialsClassGoil-wellcementwasused.TheHandDwereusedastheagents.ThepropertiesoftheHandDareshowninTable1.FiltratelossadditiveF17BandcrystalloidexpandingagentF17Awereusedtoevaluatethecompatibilityoftheadmixtures.DragreducerUSZ(w=0.2%,wismassfraction,thesamebelow)wasaddedintoallsamples(exceptingneatslurry)toimprovethefluidityoftheslurries.Table1PhysicalandmechanicalpropertiesofHandDMaterialDensity/(g·cm–3)Length/mmDiameter/µmYoung'smodulus/GPaTensilestrength/MPaH1.151.281003000.280.358.5010.0D0.930.9857101511.513.54255301.2PreparingslurrySlurrieswerepreparedandcuredaccordingtothestandardofAPIRP10B.[9]Thewatercementratio,m(w)/m(c),was0.44.Thepercentageofadmixturewasequaltothemassoftheadmixturedividedbythemassoftheneatcement(%,BWOC).1.3MechanicalpropertiestestsConfectingslurrieswereinjectedintothesteelmolds(25.4mmindiameterby25.4mminheight).After48hofcuringat0.1MPaand80,thecompressivestrengthandtheYoung'smodulusweretested.Preparedslurrieswereinjectedintothetrilinkmolds(10mm×10mm×6