4 3 2018-NAPS-47 Collapse Testing and Modeling of ...€¦ · § Avoid collapse of perforating gun under the high wellbore pressure. § Scallops are often machined on the tubular

NAPS-47-18AUTHORS:TomasTurkalj,MaurizioBellingardi,SebastianCravero

CollapseTestingandModelingofPerforatingGunsCarriers

Introduction§ GunsteeltubularcarriersofthePerforatinggunshaveto:

§ ProtecttheguncorefromImpactsandscratches.§ Survivetothegundetonation(minimalswelling/noruptures).§ Avoidcollapseofperforatinggununderthehighwellborepressure.

§ Scallopsareoftenmachinedonthetubularcarrieroutersurface,sotoprovideaproperrecessforburrsthatmaybegeneratedduringthebulletpenetrationtowardstheformation.

§ Collapseratingofperforatinggunsprimarilyreliesontheratingofthetubularsteelcarrieritself.Theinfluenceofmaterialstrength,pipegeometryandresidualstressesonthecollapseperformanceofasteelpipeisofgreatimportanceforcasingandtubing.Tenaris hasbeeninvestigatingthemattersinceyears,leadingtotheintroductionintheindustryofHighCollapsegradesforOCTG.

§ Inthisstudy,theeffectofscallopsonUltimateCollapsePressureofPerforatingGunCarriershasbeeninvestigated.Theprimaryobjectiveistofindacorrelation,alsocalledderating,betweenthesimple"unscalloped"geometryandseveraltypicalscalloppatterns.

NAPS-47-18/COLLAPSETESTINGANDMODELINGOFPERFORATINGGUNSCARRIERS

Agenda


• Introduction

• FiniteElementModelFeatures

• Validation(PlainPipe)

• FEMofGunCarriers

• ResultsofScallopedGunCarriers

• EffectofDensityontheDerating

• EffectofPipeGeometryandYSontheDerating

• Conclusions

• CollapseTestsofGunCarriers

• FinalRemarks

FiniteElementModel

MODELFEATURES

§ Nonlinearpost-bucklinganalysisusingRiks method(ABAQUS)

§ Full3DModelswithscallops(guncarriers)andwithout(plainpipe)

§ RepresentativeBoundaryConditionsofanactualcollapsechamber§ PressureappliedontheexteriorSurface§ ZeroRadialdisplacementatchamberO-ringlocations§ Onefixedsideofthepipe(includingPipeaxial

restriction)§ ElasticPlasticMaterial:truestress- truestraincurves§ PipeOvality andEccentricity§ WithoutResidualStresses

U1=U2=U3=0UR=0UR=0

p

AppliedBoundaryConditions

32

1


FEMValidation(PlainPipe)MODELVALIDATIONFEMofPlainPipeswerecomparedwithISO10400equationoutputswiththesameinputparameters.

Model OD av(in)

Wt av(in) D/t Ov (%) Ecc (%) Rs (Ksi) YS(Ksi) Pult ISO

(psi)

PultFEA

(psi)e%

Pipe-1 4.5 0.4 11.5 0.5 2.8 0 132 22591 22933 2

Pipe-2 7 0.5 14.3 0.3 8.4 0 145 18325 17648 4

Pipe-3 7 0.5 14.3 0.3 8.4 0 132 16971 16379 3

Pipe-1Collapsed

ISOTR10400- UltimateCollapse Pressure(Pult)1

(1)AnnexF.4ISO/TR10400:2007.“Petroleumandnaturalgasindustries—Equationsandcalculationsforthepropertiesofcasing,tubing,drillpipeandlinepipeusedascasingortubing


AveragedPercentageError=3%

FEMofGunCarriersSTUDIEDSCALLOPPATTERNSANDGEOMETRIES§ Densities:12spf,6spf

§ Phases:90º,135º,180º

§ Thesamescallopgeometrywasusedinallmodels

5.5mm

31.6mm

2mm

ScallopGeometry

12spf 6spf

90º 135º 180º 135º 180º


FEMofScallopedGunCarriers


FEMResultsofScallopedGunCarriersULTIMATECOLLAPSEPRESSUREDETERMINATIONVIAFEM

§ Thederating oncollapsewasobtainedforeachscallopedconfiguration

Group OD (in)

Wt(in) D/t YS(ksi) Ov (%) Ec (%) Model Phase SPF Pult

(psi)Derating

Pult Gun/Pult Pipe

1 4.5 0.4 11.5 132 0.5 2.8

Pipe-1 - 0 22933 --Gun-1 90 12 18883 0.823Gun-2 135

1356 20515 0.895

Gun-3 12 19130 0.834Gun-4 180 6 18927 0.825Gun-5 180 12 15468 0.675

2 7 0.5 14.3 145 0.3 8.4Pipe-2 - 0 18325 --Gun-6 90 12 16171 0.882Gun-7 135 12 17055 0.931

3 7 0.5 14.3 132 0.3 8.4Pipe-3 - 0 16971 --Gun-8 135 12 15649 0.922

180º,12spf135º,12spfNAPS-47-18/COLLAPSETESTINGANDMODELINGOFPERFORATINGGUNSCARRIERS

EffectofDensityontheDerating

Effect of Density:

Derating curves of Pult depends on SPF andphase


EffectofDensityontheDerating


EffectofPipeGeometryandYSonthederating

12SPF,Phase135° ,YS=132Ksi 12SPF,Phase135°,D/t=14.3

(Ksi)

EffectofGeometry

Effect of Pipe Geometry:

Effect of Scallops pattern on Pult changes depending Pipe Dimensions.

Effect of YS:

YSslightlymodifytheeffectofthescallopsonPult


FEMConclusions

• TheFEMofplainpipeshavebeenvalidatedwiththeISOTR10400equationè PercentErrorabout3%.

• Plainpipesandguncarrierswithhelicalscalloppatternsshowedacorrectpostbucklingbehavior.

• Themachiningofthescallopsproducesderating ofthecollapseresistance,whichdependson:

• Density(quantityofremovedmaterial)ANDPhase(distributionofscallops).

• PipeGeometry(ThesamepatternofscallopsreducesPult differentlydependingonpipegeometry)

• YSdidnotshowasignificanteffectonthederating.


CollapseTestsofGunCarriers

Thetestingprogramincluded:§ CollapseTestsofPipesandScallopedPGCarriers

§ 7”ODx0.5”wt§ 4.5”ODx0.375”wt§ ScallopDensity/Phase:12SPF,135°

Complementarytests

§ ResidualStressmeasurements(SlitRingMethod)§ TensileTests(FullStripTensilesamples)

CollapsedPipes/Guns

135º,12spf Scallopgeometry


CollapseTestsofGunCarriersRESULTS

• YSandRSaveragedfromadjacenttestsamples(*)Second derating obtained from ISOPult

# Type OD x wt D/tAvActual

YS(Ksi)

Ov(%)

Ec(%) Rs (Mpa) SPF Phase Pult (Psi)

Average(Psi)

ISOPult(Psi)

AvPult ISOPult

Derating

Test-1Pipe

7” x 0.5”

14.3

145

0.35 8.4%-260 -- --

1684017020

1678017061Test-2 14.2 0.33 6.6% 17150 17152

Test-3 14.3 0.25 5.5% 17070 17249Test-4

Gun14.3 0.20 8.2%

? 12 13516240

16663 -- - 0.979Test-5 14.3 0.24 5.9% 16960Test-6 14.2 0.25 5.5% 16790Test-7

Pipe4.5” x 0.4”

12.0

130

0.23 8.5%-230 -- --

19900Not

Collapse

2020820638Test-8 11.9 0.54 2.8% 19090 21346

Test-9 11.9 0.29 9.2% 13640 20360Test-10

Gun11.9 0.62 7.8%

? 12 13517940

18063--

0.875*Test-11 11.9 0.52 11.6% 18160 --Test-12 11.7 0.25 16.1% 18090 --

RS YS Pult

Thederating obtainedincludes2effects:• theeffectmerelyreferredtoscallops(Adressed byFEM)• Theeffectproducedbythechangeinresidualstressesfield

Isitcorrecttoassumethattheresidualstressesafterthemachiningofscallopsremainsunchanged?


FinalRemarks§ Intheanalyzedcases,thederating viaFEMwasmore

conservativethanthederating obtainedexperimentallyUnknownRSofGuns(botheffectsincluded)

FEMChangeingeometryeffect

(RS=0)

CollapseDerating

FurtherinvestigationwouldbeneededtofullyunderstandthephenomenonofmodificationofRSduetoScallopsanditinteractionwiththephenomenonpresentedinthisworktogether.

Themachiningofscallops

ModifiesGeometry ModifiesRSfields

DiminishesPult Unknown effect on Pult


(thiswork)

§ Collapseperformanceofatubularisinfluencedbymaterialstrength,pipegeometryandresidualstresses

NAPS-47-18AUTHORS:TomasTurkalj,MaurizioBellingardi,SebastianCravero

QUESTIONS?THANKYOU

Documents

4 3 2018-NAPS-47 Collapse Testing and Modeling of ...€¦ · § Avoid collapse of perforating gun under the high wellbore pressure. § Scallops are often machined on the tubular