Suc Brasil 2012 : Sesam for SURF

Ole Jan Nekstad, Product Director Sesam3 December 2012

Sesam

Sesam for Subsea Umbilicals Risers Flowlines (SURF)

© Det Norske Veritas AS. All rights reserved.

Sesam

3 December 2012

2

SURF - Subsea Umbilicals Risers Flowlines

Umbilicals – Multi-purpose service lines

Flexible riser

Subsea installationFlowlines & pipelines


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3 December 2012

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Sesam coverage of SURF

� Subsea- Sesam GeniE & Usfos for structural analysis- Sesam Marine for marine operations

� Umbilicals and flexible risers- Sesam DeepC for global analysis (ULS & FLS)- UmbiliCAD for drawing & cross section design- Helica for cross section stress and fatigue

analysis- Vivana for VIV analysis

� Risers- Sesam DeepC for riser design- Vivana for VIV analysis

� Flowlines and pipelines- FatFree for free-span calculations according to DNV RP-F105- StableLines for pipeline on-bottom stability according to DNV RP-F109- DNV-OS-F101 Code Compliance for submarine pipeline systems- PET (Pipeline Engineering Tool) for early phase pipeline assessment- Vivana for VIV analysis


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Subsea coverage


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Subsea coverage

� Structural analysis (ULS, FLS, ALS)- Linear structural analysis

- Sesam GeniE product line- Code checks well equipped to cater for the hydrodynamic

pressures

- Accidental (non-linear) analysis- Usfos: Bottom impact, dropped objects, explosions, fish trawlers…..- Sima: Pipeline installations

� Marine operations- Sima for lifting & transportation

- Manifold or subsea structure lowering….


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Umbilical coverage- Component design- Cross section analysis- ULS analysis (100 year scenario)- Fatigue analysis- VIV


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Umbilicals – characterized by their flexibilityPower cable/umbilical Steel tube umbilical Control umbilical


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Umbilicals - UmbiliCAD

� A tailor-made drawing and cross section design tool- It will help you make drawings and capacity curves

� Drawings within hours in stead of days - no need to be a skilled draftsman

� Early cross section analysis – first results within hours in stead of days- Linear analysis with no stick/slip

� UmbiliCAD is developed by UltraDeep and marketed by DNVS

Capacity Curve

0.0

100

200

300

400

500

600

700

800

900

1000

1100

1200

0.0 0.04 0.08 0.12 0.16 0.2 0.24 0.28Curvature [1/m]

Tens

ion

[kN

]

100% Utilisation

80% Utilisation

Parameter

Outer DiameterMass Empty

Mass Filled

Mass Filled And Flooded

Submerged Weight Empty

Submerged Weight FilledSubmerged Weight Filled And Flooded

Specific Weight Ratio

Subm. Weight. Dia. Ratio

Axial Stiffness

Bending StiffnessBending Stiffness (friction free)

Torsion Stiffness

Tension/Torsion Factor

Value

133.235.9

39.4

42.4

21.6

25.128.1

3.0

210.8

677.3

21.316.7

27.5

0.00

Unit

[mm][kg/m]

[kg/m]

[kg/m]

[kgf/m]

[kgf/m][kgf/m]

[-]

[kgf/m^2]

[MN]

[kNm^2][kNm^2]

[kNm^2]

[deg/m/kN]


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3 December 2012

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Umbilicals - Helica

� Cross-sectional load sharing analysis- Load-sharing between elements considering axis-symmetric analysis - Cross-sectional stiffness properties from UmbiliCAD (axial, torsional and bending stiffness) - Helix element bending performance analysis to describe stresses in helix elements during

bending considering stick/slip behaviour due to interlayer frictional forces

� Short-term fatigue analysis - To assess the fatigue damage in a stationary short-term environmental condition considering

fatigue loading in terms of time-series of simultaneous bi-axial curvature and effective tension produced by global dynamic response analysis

- Helica uses results from Sesam DeepC as the response database for time domain global dynamic analysis as loading

� Long-term fatigue analysis - To assess the long-term fatigue damage by accumulation of all short-term conditions

xv θv

rv


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3 December 2012

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Design of umbilicals – a typical process

� UmbiliCAD, Helica, Sesam DeepC

10

Parameter

Outer DiameterMass Empty

Mass FilledMass Filled And Flooded

Submerged Weight EmptySubmerged Weight FilledSubmerged Weight Filled And Flooded

Specific Weight RatioSubm. Weight. Dia. Ratio

Axial StiffnessBending StiffnessBending Stiffness (friction free)Torsion StiffnessTension/Torsion Factor

Value

133.235.9

39.442.4

21.625.128.1

3.0210.8

677.321.316.727.50.00

Unit

[mm][kg/m]

[kg/m][kg/m]

[kgf/m][kgf/m][kgf/m]

[-][kgf/m^2]

[MN][kNm^2][kNm^2][kNm^2][deg/m/kN]


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Why UmbiliCAD and Helica?

� It is quick and simple to design and draw umbilical cross-sections with UmbiliCAD

� The Helica cross-section model is automatically generated by UmbiliCAD (mass & stiffness)

� Automatic generation of capacity curves (linear & with stick/slip)

� Consistently handling the internal friction in fatigue calculations

� Very high numerical performance


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Riser coverage, based on results from- a global coupled analysis- a refined approach using results from global coupled analysis or known displacements (time-series)

- vortex induced vibrations


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Riser configurations handled by Sesam DeepC

Configuration according to principle for compensation of floater motions

� Compliant/flexible risers- Floater motions absorbed by change in

configuration geometry

� Hybrid risers- Free standing vertical riser column

de-coupled from dynamic floater motions by means of compliant jumpers

� Top tension/vertical risers- Vertical risers supported by top tension.

Heave compensators allowing for relative riser/floater heave motion


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Types of analysis covered

� ULS- Deflections, forces, stresses and code check results- Sesam DeepC (Simo + Riflex)

� FLS- Global and refined fatigue- Sesam DeepC (Simo + Riflex)

� VIV- Response frequencies and fatigue damage- Cross-flow and in-line- Vivana


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VIV - Vivana

� Vivana is developed by Marintek and NTNU and marketed by DNVS

� Closely related to Riflex which is part of Sesam DeepC

� The fluid structure interaction is described by empirical, coefficient based models

� Finite element method is used to model the structure

Marintek tests for Norsk Hydro


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VIV – Vivana, analysis types

� Static and dynamic analysis- Uses the model and static analysis from

Sesam DeepC (Riflex)- Finite element method- Non-constant properties; e.g. diameter,

stiffness- Sheared current- Uneven seafloor- 3D response; sag and current deflection

included

� VIV analysis- Frequency domain- Discrete response frequencies- Response frequencies are assumed to be

eigen-frequencies found with adjusted added mass

- VIV loads from semi-empirical coefficient based models- Cross-Flow (CF) VIV excitation only- In-Line (IL) VIV excitation only

Pure ILresponse

Combined IL and CF


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3 December 2012

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Pipeline design based on the DNV standards- FatFree, RP-F105- StableLines, RP-F109- Code compliance, OS-F101- PET (Pipeline Engineering Tool)


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Free span analysis – to avoid VIV and fatigue problems

Free spans

� Avoid costly repair

� Predict stable delivery of oil or gas

� Prevent pollution

� Avoid seabed correction and span intervention

� Rule based (DNV) or VIV analysis (Vivana)

Unevenseabed

Free span with span intervention

Scour


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Analyse before you install

� Typical example on fatigue damage of pipeline


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FatFree, RP-F105


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3 December 2012

Slide 21

Pipeline free spans

� Free spans can cause problems and must be taken seriously

� The problem is fatigue which is caused by cyclic loads from VIV

� VIV is a classic fluid-structure interaction problem and the response is caused by resonance between the vortex shedding frequency and the natural frequency of the span.

� Fatigue damage for a given span under defined environmental conditions can be calculated by FatFree, which is based on RP-F105


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3 December 2012

Slide 22

Failure Modes

Fatigue Limit State

.. accumulated damage from stress cycles caused by:

� Vortex Induced Vibrations(in-line & cross-flow) (RP-F105)

� Direct Wave Loads (RP-F105)

Ultimate Limit State

.. over-stress (local buckling) due to:

� Static Bending (weight & current) (DNV OS-F101)

� VIV & Wave Loads (RP-F105)

� Pressure Effects (DNV OS-F101)

� Axial Force (DNV OS-F101)

� Trawl interference (GL 13)


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FatFree, based on DNV-RP-F105

12.06.2006 Vers. 10.0

DNV version Expiry date: 31.12.2007 Release Note

Project: Date: 12.06.2006 Calculations byNo Wave Case References: verification of version Verified by

h [m] 300 fo(in-line) 0,773 ζstruc 0,000 m1 3

L [m] 40 fo(cr-flow) 0,798 ζsoil (in-line) 0,000 m2 3 η 1,00

e [m] 2,69 A in (in-line) 446 ζsoil (cr-flow) 0,000 Log(C1) 11,222 γk 1,00

d [m] 0 Acr (cr-flow) 461 ζh,RM 0,000 Log(C2) 11,222 γf,IL(inline) 1,00θpipe 0,0 λmax 940 KS(in-line) 0,00 logNsw 8,00 γf,CF(cr-flow) 1,00

D [m] 0,612 δ/D 0,24 KS(cr-flow) 0,00 S0 [MPa] 0,00 γS 1,00

L/D 65 Seff/PE -0,23 KV 2,105E+07 SCF 1,00 γon,IL 1,10

KL 1,592E+07 γon,CF 1,00KV,S 5,300E+05 ΨR 1,00

kc 0,33 Heff [N] 2,00E+05 Ds 0,5000 ν 0,30 ρsteel 7850

fcn (MPa) 45 p [bar] 105 tsteel 0,0132 α [oC-1] 1,17E-05 ρconcrete 2240∆T [oC] 0 tconcrete 0,0500 E [N/m2] 2,07E+11 ρcoating 1300

tcoating 0,0060 CD(current) 1,00 ρcont 153

RESULTS

In-line (Response Model) 1,09E+03 yrs

Cross-Flow 1,00E+06 yrs Peak Von Mises Peak Von Misesσσσσx(1 year) 0,0 158,2 σσσσx(1 year) 7,2 135,2

In-line (Force Model) - yrs σσσσx(10 year) 0,0 158,2 σσσσx(10 year) 16,7 141,4In-line (Combined) - yrs σσσσx(100 year) 0,0 158,2 σσσσx(100 year) 26,1 148,6

Current Modelling

Code

Directionality

Current

Current Sheet Name

Calculation options

Return Period Values

FATFREE IS READY

FATIGUE ANALYSIS OF FREE SPANNING PIPELINESMuthu Chezhian ([email protected])

Olav Fyrileiv ([email protected])

Programmed by DNV Deep Water Technology

Kim Mørk ([email protected] )FATFREE

Safety FactorsSoil PropertiesResponse Data SN-Curves

Densities [kg/m3]

DYNAMIC STRESS [MPa]

Wave Modelling

FATIGUE LIFE

STRUCTURAL MODELLINGConstants

InlineCross-flow

Pipe Dimensions [m]Coating data

Free Span Scenario

Wave Sheet NameWave-template

Functional Loads

Flat sea-bed RP-F105 Span User DefinedF1 (free corrosion)

CALCULATE

UPDATE SHEET

PRINT RESULTSSPAN RUNS

USER HELP

OPTIONS

No Wave

Discrete - C dir.

Uc Histogram

RP-F105

Automatic Generated

Damage distribution vs direction

0,0

0,2

0,4

0,6

0,8

1,0

1,2

0 20 40 60 80 100θθθθ

RM (In-Line)FM (In-Line)Cross-FlowComb.(In-Line)

pdf for omnidirectional current

0,0

1,0

2,0

3,0

4,0

5,0

0,0 0,2 0,4 0,6 0,8 1,0

RM(cross-flow)*4

RM(inline)*10

velocity

User DefinedSingle-mode

Well defined


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3 December 2012

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StableLines, RP-F109


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3 December 2012

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StableLines based on DNV-RP-F109 (2007)

� Making safe decisions on necessary weight simpler

� Three lateral stability methods are covered; - Absolute stability, No pipeline movement- Generalized stability with 0.5xOD or 10xOD displacement

� Any parameter may be varied, to help designers create good criteria for the relevant conditions of their projects.

� Important sensitivity studies are performed and reported automatically

� Pipelines and umbilicals on the seabed are influenced by hydrodynamic forces generated by waves and currents

� The only resisting forces are due to seabed interaction

� Fhydrodynamic > Fsoil resistance = Unstable pipeline

FR

Fwaves

Fcurrent


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3 December 2012

Soil conditions

� Clay- Friction coefficient set to µ = 0.2- Pipe penetration automatically calculated- Sensitive to undrained shear strength, su

� Sand- Friction coefficient set to µ = 0.6- Pipe penetration automatically calculated- Insensitive to submerged unit soil weight, γs

’

� Rock- Friction coefficient set to µ = 0.6- Pipe penetration = 0


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3 December 2012

Metocean/Environmental data

� Waves- Based on observation of the waves in the area of the pipeline- Scatter diagram used to derive statistical wave models.- Most important statistical values:

- Significant wave height, Hs

- Peak period, Tp

- Surface waves transferred down to the seabed by a transfer function- Oscillating water particle velocity

� Current- Usually assumed to be constant for a given RPV- Constant current speed (water particle velocity) given

� RPV- Return Period Value- 1, 10 or 100 year storm


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3 December 2012

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StableLines – easy to making safe and good decisions

� Sensitivities to the most critical design parameters are presented in curves, which allow the designer to assess the implications of inaccuracies with ease

� Easy to understand curves for good decision making on important design choices

Concrete thickness vs. Water depth

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

40 50 60 70 80 90 100

Water depth [m]

Co

ncr

ete

thic

knes

s [m

]

Empty condition

Operationalcondition


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3 December 2012

StableLines - Output


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Code compliance, OS-F101


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3 December 2012

Slide 31

Scenarios and failure modes

Scenario

Pressure X X X X

Installation X X X X X X X

Free-span (x) X X

Global Buckling (x) X X X X

Trawling (x) X X X

On bottom stability

(x) X X X X X

Pipeline Walking X X X X

Bur

stin

g

Col

laps

e

Pro

paga

ting

buck

ling

Com

bine

d Lo

adin

g

Fat

igue

Fra

ctur

e

Den

t

Ova

lisat

ion

Rat

chet

ing


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3 December 2012

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DNV OS-F101

� Code compliance with DNV OS-F101

� Supported code checks- Burst (pressure containment) related to both system test condition and operation- Collapse for an empty pipeline- Propagating buckling for an empty pipeline- Load controlled load interaction (moment, axial force and external/internal overpressure)- Displacement controlled load interaction (axial strain and external/internal overpressure)

� The program calculates- The minimum required wall thickness

for the given conditions- Utilisation based on a wall thickness

given by the user


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3 December 2012

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DNV OS-F101 – Easy to use and easy to understand

� All input at a glance & Output in engineering terms


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PET (Pipeline Engineering Tool) – or (Pipeline EarlyDesign Tool)


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PET – Pipeline Engineering Tool

� PET – a calculation tool for early phase pipeline assessment- DNV-OS-F101 Design Checks- Weight and Volume- End Expansion- Upheaval Buckling- On-Bottom Stability- Fatigue Screening- Reel Straining- Reel Packing- J-Lay- S-Lay- Cathodic Protection

� FatFree, StableLines, DNV OS-F101 are used for more thorough studies


Sesam

3 December 2012

Slide 36

PET – Weight and Volume

� Calculates volume, mass and dry weight of the components that constitute a pipeline, i.e. steel, coating layers and content.

� Volume, mass and dry weight are calculated individually and totally, per metre pipeline and totally for a given length of the pipeline.


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3 December 2012

Slide 37

PET – End Expansion

� A pipeline with internal pressure and temperature increase will want to expand axially

� Pipe soil interaction will reduce/prevent axial expansion

Free end will expand

Anchor length

Maximum effective axial force, no axial expansion

Soil resistance

Effective axial force increases from zero to maximum due to soil resistance


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3 December 2012

Slide 38

PET – End Expansion

� Report – print to paper or *.pdf


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3 December 2012

Slide 39

PET – Upheaval Buckling

� Safety level for given input

� Temperature, internal pressure and imperfection height that will trigger upheaval buckling

� Cover height to prevent upheaval buckling for a given safety level

� Simple and approximate, not necessarily conservative


Sesam

3 December 2012

Slide 40

PET – On-Bottom Stability

� Safety level for given input

� Weight coating required to ensure stability for a given safety level and

� Steel wall thickness required to ensure stability for a given safety level.

� Calculations according to DNV-RP-E305


Sesam

3 December 2012

Slide 41

PET – Fatigue Screening

� Critical span length according to VIV on-set screening criterion in DNV-RP-F105

� In-line� Cross-flow


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3 December 2012

Slide 42

PET – Reel Straining

Installation by reeling:� What is the maximum strain and ovality on the reel?� Is the criterion in DNV-OS-F101 satisfied?� How much plastic strain accumulates?


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3 December 2012

Slide 43

PET – Reel Packing

� Amount of pipe on given reel according to

- Volume restriction and - Weight restriction


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3 December 2012

Slide 44

PET – J-Lay (also applicable for reeling)


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3 December 2012

Slide 45

PET – J-Lay

Calculates:� Top tension� Curvature and moment in sag bend

including utilisation ratio according to DNV-OS-F101

� Distance from touch down to barge� Length of pipe in the free span� Minimum horizontal lay radius

� Note: Catenary calculations, i.e. approximate


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3 December 2012

Slide 46

PET – S-Lay


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3 December 2012

Slide 47

PET – S-Lay

Calculates:� Top tension� Strain on stinger including utilisation ration

according to DNV-OS-F101� Curvature and moment in sag bend including

utilisation ratio according to DNV-OS-F101� Distance from touch down to barge� Length of pipe in the free span� Minimum horizontal lay radius

� Catenary calculations, i.e. approximate


Sesam

3 December 2012

Slide 48

PET – Cathodic Protection

� Calculated anode requirement according to DNV-RP-F103 to ensure:

- sufficient anode material to cover mean loss throughout the design life.

- sufficient current at the end of design life for de-polarisation.

- maximum spacing


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3 December 2012

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Sesam has a high coverage for- Subsea- Umbilicals- Risers- Flow and pipelines


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3 December 2012

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Concluding remarks

50

Structural analysis & marine operations

Global analysis, cross section design, fatigue and VIV

Strength assessments, fatigue and VIV

Pipeline engineering tools according to DNV practices


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3 December 2012

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Safeguarding life, property and the environment

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