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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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
3
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
4
Subsea coverage
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
5
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….
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
6
Umbilical coverage- Component design- Cross section analysis- ULS analysis (100 year scenario)- Fatigue analysis- VIV
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
7
Umbilicals – characterized by their flexibilityPower cable/umbilical Steel tube umbilical Control umbilical
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
8
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]
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
9
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
10
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]
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
11
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
12
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
13
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
14
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
15
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
16
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
17
Pipeline design based on the DNV standards- FatFree, RP-F105- StableLines, RP-F109- Code compliance, OS-F101- PET (Pipeline Engineering Tool)
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
18
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
19
Analyse before you install
� Typical example on fatigue damage of pipeline
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
20
FatFree, RP-F105
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
Sesam
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)
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
23
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
24
StableLines, RP-F109
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
25
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
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
28
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
StableLines - Output
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
30
Code compliance, OS-F101
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
32
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
33
DNV OS-F101 – Easy to use and easy to understand
� All input at a glance & Output in engineering terms
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
34
PET (Pipeline Engineering Tool) – or (Pipeline EarlyDesign Tool)
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
35
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
© Det Norske Veritas AS. All rights reserved.
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.
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
Slide 38
PET – End Expansion
� Report – print to paper or *.pdf
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
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
© Det Norske Veritas AS. All rights reserved.
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
© Det Norske Veritas AS. All rights reserved.
Sesam
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?
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
Slide 43
PET – Reel Packing
� Amount of pipe on given reel according to
- Volume restriction and - Weight restriction
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
Slide 44
PET – J-Lay (also applicable for reeling)
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
Slide 46
PET – S-Lay
© Det Norske Veritas AS. All rights reserved.
Sesam
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
© Det Norske Veritas AS. All rights reserved.
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
49
Sesam has a high coverage for- Subsea- Umbilicals- Risers- Flow and pipelines
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
50
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
© Det Norske Veritas AS. All rights reserved.
Sesam
3 December 2012
51
Safeguarding life, property and the environment
www.dnv.com