【7A文】钻井工程英文课件1.7 Pressure Drop Calculations.ppt

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1、1PressureDropCalculations1.7-121.7-231.7-3FormultiplenozzlesinparallelVnisthesameforeachnozzleevenifthednvaries!ThisfollowssinceDpisthesameacrosseachnozzle.&Cd=0.9541.7-4HydraulicHorsepower…ofpumpputtingout400gpmat3,000psi=?Power,infieldunits:HydraulicHorsepowerof

2、Pump=700hp51.7-5WhatisHydraulicImpactForce…developedbybit?If:61.7-6LaminarFlowRheologicalModelsNewtonianBinghamPlasticPower-Law(ADE&API)RotationalViscometerLaminarFlowinWellboreFluidFlowinPipesFluidFlowinAnnuli7LaminarFlowofNewtonianFluidsExperimentally:1.7-781.7-

3、8NewtonianFluidModelInaNewtonianfluidtheshearstressisdirectlyproportionaltotheshearrate(inlaminarflow):i.e.,Theconstantofproportionality,istheviscosityofthefluidandisindependentofshearrate.91.7-9NewtonianFluidModelViscositymaybeexpressedinpoiseorcentipoise.101.7-1

4、0ShearStressvs.ShearRateforaNewtonianFluidSlopeofline=m.111.7-11TypicalDrillingFluidVs.Newtonian,BinghamandPowerLawFluids0121.7-12RheologicalModels1.NewtonianFluid:2.BinghamPlasticFluid:Whatifty=0?131.7-13RotatingSleeveViscometer141.7-14Figure3.6RotatingViscomet

5、erRheometerWedeterminerheologicalpropertiesofdrillingfluidsinthisdeviceInfiniteparallelplates151.7-15Rheometer(RotationalViscometer)ShearStress=f(DialReading)ShearRate=f(SleeveRPM)ShearStress=f(ShearRate)161.7-16ExampleArotationalviscometercontainingaBinghamplasti

6、cfluidgivesadialreadingof12atarotorspeedof300RPMandadialreadingof20atarotorspeedof600RPMComputeplasticviscosityandyieldpointq600=20q300=12SeeAppendixA171.7-17Exampleq600=20q300=12(SeeAppendixA)181.7-18GelStrength191.7-19GelStrength=shearstressatwhichfluidmovementb

7、eginsTheyieldstrength,extrapolatedfromthe300and600RPMreadingsisnotagoodrepresentationofthegelstrengthofthefluidGelstrengthmaybemeasuredbyturningtherotoratalowspeedandnotingthedialreadingatwhichthegelstructureisbroken(usuallyat3RPM)201.7-20GelStrengthInfieldunits,I

8、npractice,thisisoftenapproximatedtoThegelstrengthisthemaximumdialreadingwhentheviscometerisstartedat3rpm.tg=qmax,3211.7-21VelocityProfiles(laminarflow)