INTRODUCTIONTODRILLINGBIT钻头英文简介

DRILLBITSELECTIONOneofthemoreconfusingaspectsofoilwelldrillingtotheyoungandoldalikeisthenumeroustypesofdrillbits.Thelargestmanufacturerofdrillbitsmakes34typesand33sizes(diameters)andmanymoreonrequest.IADCorganizationhasasystemofassigningadesignationcodetoeachbittype.ROLLERCONE1.Series2.Type3.Feature4.Feature(2)ROLLERCONEStandardRollerBearingRollerBearingAirCooledRollerBearingGaugeProtectedSealledRollerBearingSealledRollerBearingGaugeProtectionSealedFrictionBearingSealedFrictionBearingGaugeProtectionSERIESFORMATIONSTYPES1Softformationswithlowcompressivestrenghtandhighdrillability12342Mediumtomed-hardformationswithhighcompressivestrenght12343Hardsemi-abrassiveandabrassiveformations12344Softformationswithlowcompressivestrenghtandhighdrillability12345Softformationswithlowcompressivestrenght12346Mediumhardformationswithhighcompressivestrenght12347Hardsemi-abrasiveandabrassiveformations12348Extremelyhardandabrasiveformations123456Milled-ToothBits12DirectionalOtherInsertBitsIADCBITCLASSIFICATIONFORMFEATURES78934CODEFEATURECODEFEATUREAAirapplicationNBOCCenterjetPDDeviationcontrolOEExtendedjetsRReinforcedweldsFSStandardsteelteethGExtragauge/bodyprotectionTHUIVJJetdeflectionWKXChiselinsertLYConicalinsertMZOtherinsertFEATURE(2)ExampleCode:522R5=codeforinsertbits“2=codeforsofttomediumformation“2=codeforrollerbearingaircooled“R=codeforreinforcedweldsFIXEDCUTTERS1.Cuttertypeandbodymaterial,2.Cross-sectionprofile,3.Hydraulicdesign,and4.CuttersizeanddensityFIXEDCUTTERSFirstcodedesignationsareD-naturaldiamond/matrixbodyM-polycrystallinediamondcutters/matrixbodyS-polycrystallinediamondcutters/steelbodyT-thermallystablepolycrystallinediamondcutters/matrixbodyO-otherSecondcodedesignationsare1.longtaper/deepcone2.longtaper/mediumcone3.longtaper/shallowornocone(parabolic)4.mediumtaper/deepcone5.mediumtaper/mediumcone6.mediumtaper/shallowornocone(rounded)7.shorttaper/deepcone(inverted)8.shorttaper/mediumcone9.shorttaper/shallowornocone(flat)Thirdcodedesignationsare1.bladed/changeablejets2.bladed/fixedports3.bladed/openthroat4.ribbed/changeablejets5.ribbed/fixedports6.ribbed/openthroat7.openface/changeablejets8.openface/fixedports9.openface/openthroat10.alternativecodesa.radialflowb.crossflowc.otherFourthcodedesignationsare1.cuttersize;large,medium,andsmall2.cutterdensity;light,medium,heavyExampleCode:M582M=codeforpolycrystallinediamondcutters/matrixbody“5=codeformediumtaper/mediumcone“8=codeforfixedports/openface“2=codeformediumcuttersize/lightcutterdensityDrillBitCharacteristics1.Teethlengthandsize2.Numberofteeth(indexing)3.Coneoffset4.Conebearingtype5.Heelrowteethconfiguration6.Gaugeconfiguration7.Journalshaftangle(howflatorroundthebottomholepattern)TheteethlengthandsizeandconeoffsetaffecttheROPThenextthreeitemsonthelisthavealargeaffectonthebitlife.Item7affectsholestraightness.Rollerconedrillbitcharacteristicsofimportanceinregardtoselectionare:ROCKFAILUREMODELSTworockfailuremodelsarerecognized:thetensionandshearIthasbeenarguedthatthesheartypeactionismoreefficientthanthetensionmodel.DRILLBITSELECTIONCRITERIAApopularequationforcostcomparisonsisthetotalcostperfootequation.Ifthebitwereoperatedtoitsoptimallifeatitsoptimumweightandspeed,thenthecostwouldbethelowestcostperfootforthebit.FootageBitTDownTRotTTripOprBitTCFIsthebitlifeifthebitisterminatedby1.Bearingfailure,2.Totaltoothwear,or3.Thereductionofitsdrillingratetoanuneconomicalone.p.s.Formationchangesoftenmaskthelatteroptimallifeandcaremustbeexercised.OPTIMALLIFEExampleFollowingperformancedataisgiven:ITEMSTEELTOOTHINSERTTOOTHBitCost$277.88$1521.32Trip6:18hrs/min6:32hrs/minRotationTime10:01hrs/min58:42hrs/minDownTimeNoneNoneBitFootage180ft880.5ftRigCostRate375$/hrSameFractionToothWear1/2NotApplicableFractionBearingWear6/88/8AverageDrillingRate18ft/hr12.5ft/hrBitSize7-7/8in.7-7/8in.BitWeight30,000lbs40,000lbsRotarySpeed85rpm60rpmft54.35$TCF1801.10)1.103.6(37588.277TCFSteelSteelft28.35$TCF5.1258)583.6(37532.1521TCFInsertInsertTheplotshowsthathadthesteeltoothbitbeenpulledatitsoptimallife(6hoursand34minutes)itwouldhavehadalowercostperfoot:$34.05/ftversus$35.47/ft.20406080100120140160050100150200OPTIMALBITLIFEBITFOOTAGE(ft)optimalTCF$/ft05101520.05.010.015.020.0ROUNDTRIPTIMEDEPTH1000ftTRIPTIME(hours)TriptimesmaybetakenfromtheIADCtoursheetormaybetakenfromtheGeolographunitorsomeotherdevice.Achartversusdepthmustbeconstructedforeachrigforultimateanalyses.TRIPTIMEExampleAbitisrunatadepthof8,000feetandpulledatadepthof8,500feet.Howmanyhoursisthetriptimeforthisbit?05101520.05.010.015.020.0ROUNDTRIPTIMEDEPTH1000ftTRIPTIME(hours)TripT=(5.2+5.7)/2=5.45hrFromthechartaroundtripsat8,000feetand8,500feetrequire5.2hoursand5.7hours,respectively.OPTIMALWOB&RPMThepurposeofselectingbitweightandrotaryspeedsareto1.producethelowestdrillingcostperfoot2.controlthedirectionofthedrillhole3.findoverpressuredzones4.satisfyequipmentlimitations(solidsremoval,BHA,etc.)5.developasatisfactorycuttingsdescriptionlogCONTOURMETHODThemethodconsistsofconstructingthepreviousfigure