Transcript No Slide Title

PRESENTATION PREPARED FOR SUBSEA SOLUTIONS 06
Current Riser & Subsea Technology
Issues being addressed by MCS
Dr Patrick O’Brien, Director, MCS
11th May 2005
An ISO 9000 Company
Presentation Overview
• Fatigue of Flexible Pipe and Steel Tube Umbilical
Risers
– Progress on recent development work
– Upcoming STU Prototype Testing
• Subsea Integrity Management
– The SCRIM Joint Industry Project
• Deepwater Pipelay analysis
• MCS Pleased to Sponsor the Technical Seminar
Programme for Subsea Solutions 06
– Importance of Paris as a hub for West of Africa business by
our recent opening of an MCS Paris office
System Architecture: Girassol Subsea
Flexible Pipes and Steel Tube Umbilicals
Flexible Pipe
Integrated Production
Bundle
Steel Tube Umbilical
Flexible Pipes and Steel Tube Umbilicals
• All an integral part of the
SURF scope of supply
• All include helically wound
components
• Friction between layers or
helically wound
components
• Need to model behaviour of
helically wound
components on a bent
pipeline or umbilical
Flexible Pipe
Steel Tube Umbilical
• Fatigue Design important
for Risers
Integrated Local-Global Modelling
• Stick-Slip Bending
– Armour / tube initially sticks on reverse bending
– Slip is inline with and transverse to lay-direction
– Hysteretic fatigue stress
Wire Stress (MPa)
150
100
50
Regular
Stress
Cycle
0
-50
-100
-150
-0.1
-0.05
0
0.05
Pipe Dynamic-Curvature (rad/m)
0.1
Flexible Pipe and STU Fatigue Design
• MCS managed programmes
– Real Life JIP
• Emphasis on global analysis
• Interface between global and local pipe loads
– DTI – Fatigue Analysis Tool for Flexible Pipes
• Specifically established to embody methodologies
recommended by Real Life JIP
• Focus on local pipe stress analysis
– Tensile armours
– Pressure armours
– Fatigue Life Testing of Steel Tube Umbilicals
• Jointly between MCS and COPPE
• Testing of manufacturer prototypes and model calibration
Wire or Tube Equations of Equilibrium
Helically Wound Components
d 11
t   12 ,tot  0
ds
Tangential
11t n   22,diff  0
Surface Normal
 11tt   32,tot  0
• Method of Solution
2
3
Transverse
– Incremental curvature determines incremental non-slip axial
stress
– Incremental non-slip axial stress determines incremental
tangential shear, normal interface and tranverse shear stresses
– Check Coulomb law and gradually relax stresses while retaining
equilibrium
– Wire curvatures from loxidromic / geodesic equations
1
Friction-Induced Stress
• MCS Structural Model for Friction – Irregular Loading
Wire Stress
0.025
0.02
0.015
0.01
0.005
0
-0.005
-0.01
-0.015
-0.02
-0.025
100
80
Stress (MPa)
60
40
20
0
-20
-40
-60
-80
0
10
20
30
40
50
60
0
10
20
Time (s)
30
Time
Hysteresis Loop
100
80
60
Stress (MPa)
Curvature (rad/s)
Pipe Bending Curvature
40
20
0
-20
-40
-60
-80
-0.02
-0.02
-0.01
-0.01
0.00
0.01
Pipe Curvature (rad/m)
0.01
0.02
0.02
40
50
60
3D (out-of-plane) Irregular Seas
3D Pipe Bending in Irregular Seas
Hs = 2m, Tp = 13s, 15deg off-bow
Global Tension (left) and Curvature (right) Responses
1.70E+06
0.008
0.006
1.65E+06
0.004
0.002
1.55E+06
0
1.50E+06
-0.002
1.45E+06
-0.004
1.40E+06
-0.006
15
35
55
75
95
115
Time (s)
Tension
Local-y Pipe Curvature
Local-z Pipe Curvature
Curvature (rad/m)
Tension (N)
1.60E+06
Tensile Armour Stress Validation
Total Stress on Initial Intrados Side of Pipe
Inner Tensile Armour
Real Life Trial Application No. 2, Regular Wave Height = 8.5m, Period = 13.0s
900
850
Stress (MPa)
800
750
700
BFLEX
MCS
650
600
550
500
450
-0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
Pipe Curvature (rad/m)
• MCS stress computed almost instantaneously from global loads
Fatigue Analysis Highlights
• Closely integrated with global analysis
– Takes timetraces directly from the global analysis
• Tensions & component curvatures
• Regular or irregular responses
– Computes stress timetraces that are cycle (rainflow) counted
• Local analysis supports 3D bending of pipe / umbilical
– Fully accounts for global directionality
– Wire stress computed at several locations
– Economically processes several loadcases
• Validated as part of the Real Life JIP
• Hysteresis effects applied to reduce conservatism
– In either a semi-local or global analysis
Hysteresis: Global Modelling
– Global modelling only takes the “plastic” slope
Wire Stress (MPa)
150
100
50
0
-50
-100
-150
-0.1
-0.05
0
0.05
Pipe Dynamic-Curvature (rad/m)
0.1
Hysteresis
Pipe Friction Moment and its ElastoPlastic Decomposition
Basis Curve
Multilinear Approx.
Elastoplastic-1
Elastoplastic-3
Elastoplastic-4
Elastic-5
Elastoplastic-2
3.5E+04
Friction Moment (Nm)
3.0E+04
2.5E+04
2.0E+04
1.5E+04
1.0E+04
5.0E+03
0.0E+00
0
0.005
0.01
0.015
Pipe Curvature (rad/m)
0.02
0.025
0.03
Hysteresis
Hysteretic Reduction of Pipe Curvature
No hysteresis
with Hysteresis - 50% reduction
0.008
Curvature (rad/m)
0.006
0.004
0.002
0
-0.002
-0.004
65
70
75
80
85
Time (s)
• Improves fatigue life by factors of over 5
90
Steel Tube Umbilical X-Section Analysis
• Similar Issues to Flexible Pipe Technology
– Helically Wound Components (Tubes/Armour Wires)
– Slip / No-Slip of Tubes
– Hysteresis Effects
– Complex 3D Global Motions / Loads
– Friction Issues
– Identical approach to global fatigue analysis
Steel Tube Umbilicals
• Some Key Differences to Flexible Pipe
Technology
– Much Smaller Lay Angles (2º to 10º)
– More Complex and varied Cross-Sections
– Complex Contact Pressure Scenarios
– More Prone to Disorientation
MCS STU Technology Development
• Research Project – Fatigue Life Testing of Steel
Tube Umbilicals
• Joint Project between MCS and COPPE
– COPPE - Graduate School and Research Institute from
the Federal University of Rio de Janeiro
• Funding by Petrobras and Brazilian Government
• STU Samples from Marine Production Systems
(Oceaneering Multiflex) and Prysmian (Pirelli)
COPPE Test Rig
•Bosch-Rexroth Hydraulic System
•Tension Capacity of 225 ton
•Max Bending Moment of 200 ton.m
•Angle Range from -15° to +30°
•Sample maximum length of 12m
•Variable Tension Loads
•In or Out of Phase Load Combinations
•Full Instrumentation
•Continuous Monitoring
Summary of STU Research Project
• Full Scale Dynamic Test of Two Samples
– Using COPPE’s test rig in Rio
• Global and Local Numerical Modelling of STUs
• Calibrate MCS Cross-Section Models against
Test Results
• Preliminary Guidelines for Fatigue Analysis of
STUs
Summary of STU Research Project (cont.)
• Project Schedule
– 12 month schedule
– May ’06 to April ‘07
• Deliverables
– Qualify Two STU Designs
– Gather Full Scale Test Data
– Calibrate Models
– Preliminary Guidelines
Subsea Integrity Management
• Integrity management for subsea
components evermore important
– Deep water, remote locations: cost of
intervention
– High profile failure incidents around the world
(Brazil, GOM)
– Gulf of Mexico
• Hurricane conditions in excess of 1000 year event
• Accelerated growth in use of Steel Catenary Risers
(SCRs) combined with uncertainty in design of SCRs
• Regulator framework for riser CVA from the MMS
• All leading to an increased focus on safety and integrity
SCR Integrity Management (SCRIM) JIP
•
Primary objectives of the SCRIM
JIP have been:
–
to develop a systematic
methodology for the risk-based
integrity management of SCR
field systems.
–
to investigate best technology
in terms of inspection and
monitoring methods for SCRs,
and identify emerging
technologies for SCR inspection
and monitoring.
SCRIM JIP
PARTICIPANT STATUS
Operators
1. BP (Steering Committee Chair)
2. ExxonMobil
3. ChevronTexaco
4. Petrobras
5. Kerr McGee
6. Anadarko
7. Dominion
8. BHP Billiton
Transportation Companies
9. Williams
Contractors
10. SBM
Regulators
11. Minerals Management Service
12. Department of Transportation
Component Suppliers
13. Oil States Industries
14. RTI Energy Systems
15. Techlam
Pipe Mill
16. Tenaris
Deepwater
Pipeline
Installation
Analysis
Developed with the Industry
State of the Art User Interface
Rollerbox Modelling Options
• Range of options
provided
• Simplest can be used
in preliminary studies
– extremely fast
• Most complex
combines realistic
model with fast
solutions times
Applications
• Deep and shallow water pipeline
installation analysis
• Start-up procedures:
– Sheave
– Stab and hinge over
– Dead man anchor
• Abandonment & Recovery
• In-line structure
• SCR transfer
• And more …
Conclusions
• Leading Edge Fatigue Methodology for Flexible Pipe
and Steel Stube Umilical Risers
–
–
–
–
–
Globally integrated stress methodology
Much improved interface between global and local analyses
Numerically efficient
Generic equations to solve helically wound elements
Ongoing full scale tests to validate and calibrate
methodologies
• Subsea Integrity Mangement
– Industry iniative to develop methods for SCR integrity
management
• Pipelay analysis
– A new generation tool for dynamic pipelay analysis
The End
www.mcs.com