【7A文】Foam Drilling(泡沫钻井英文).ppt

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1、FoamDrilling(泡沫钻井英文）“Foamsconsistofacontinuousliquidphase,formingacellularstructuresurroundingandentrappingagas.”Section3-Page11MakeUp2Generation3Disposal4DrillingPractices5ProblemsDeliverenergytobitCleanthedrillingfaceCoolandlubricatePowerdownholetoolsTranspor

2、tcuttingsSuspendcuttingsTransmitdatatosurfaceStabilizeboreholeCreateanimpermeablebarrierHydrostaticcontroloverinfluxReleasecuttingsatsurfaceFunctionsofFoamasaUBDFluidSection3-Page2FoamClassificationQualityReferstothevolumeofgasexpressedasapercent.Lowandhighqual

3、ityareidentifiedbyliquidcontent.TextureDescribesthesizeanddistributionofthebubbles.Rangesfromfinefoam(smallbubbles)tocoarsefoamwithlargebubbles.Regardlessofthequalityandtexture,foamwilldecomposeovertime.Thisdecompositioniscalledit’shalflife(typicallyaround5minu

4、tes).Thisiscausedbytheindividualbubblesburstingduetoweakeningas“skin”fluiddrainsuntilburst.Section3-Page3Foamshaveveryhighviscosities,thismakesforexcellentholecleaningatmuchlowerannularvelocitiesthanisneededformistordrygasThelowdensityoffoamisidealforUBDapplica

5、tions(½theweightofwater)HigherannularpressureswithfoamcanhelpreducewellborestabilityproblemsFoamcanbeproducedbymixingasurfactantsolutionwithagasflowandinjecteditatpressureintothedrillstring.Thefoamusedinstablefoamdrillingisformedatthesurfacebymixingthesurfactan

6、tandgasinafoamgenerator.A“stiff”foamisafoaminwhichtheliquidphaseisintentionallyviscosified.Thegreatestbenefitoffoamisitsabilitytoliftlargequantitiesofproducedliquids.Section3-Page4FoamFoamStabilityThequalityoffoamwillreachaceiling-around97%to98%.Greaterthan98%w

7、illreverttoamist.Shearratescanfurtheraffectthischange.Theycanlowerthequalityasfaras94%Additionofpolymericviscosfiersimprovestabilityabove98%.Mostdrillingfoamsareinthequalityrangeof75%to97.5%.MistFoamLiquidFoamDownholeSeparationSection3-Page550100150200250300200

8、040006000800010000110120130140150160AirWater90ft/hr60ft/hr30ft/hr0ft/hrDepth(ft)AirVolumeRate(scfm)WaterRate(gpm)InjectionPressure(psi)InjectionRatesandPressures(KrugandMitc