Global Riser and Mooring Analysis Using OrcaFlex
Target Audience:
- Offshore and subsea engineers involved in riser/mooring system design
- Structural, naval architecture, and marine operations engineers
- Professionals in Deepwater development, FPSO projects, and floating systems
- Engineers seeking hands-on experience with OrcaFlex simulation tools
Course Objectives:
Upon completion, participants will be able to:
- Understand the principles of global riser and mooring system behavior
- Model, simulate, and analyze dynamic systems using OrcaFlex
- Evaluate critical design criteria such as tension, fatigue, VIV, and clearance
- Perform global response analysis for floating systems under environmental loads
- Apply OrcaFlex effectively to real-world offshore design and verification problems
Module Highlight
Introduction to Global Analysis & OrcaFlex Environment
- Overview of global analysis in offshore systems
- Applications: Risers, moorings, umbilicals, FPSOs, TLPs, buoys
- OrcaFlex GUI and file structure
- Types of simulations (quasi-static, dynamic, time-domain, frequency-domain)
- Introduction to time histories and response metrics
Modeling of Riser Systems
- Types of risers: SCRs, top-tensioned risers, flexible risers, hybrid risers
- Geometry creation (3D catenary, vertical riser, lazy wave)
- Material properties and structural parameters
- Buoyancy modules and bend stiffeners
- Boundary conditions (seabed contact, hang-off, clamped support)
- Hands-on: Modeling a steel catenary riser (SCR) from seabed to floater
Mooring System Modeling
- Types of mooring systems: catenary, taut-leg, hybrid
- Line definitions: chains, wire, synthetic rope
- Connectors, fairleads, winches, and anchors
- Pretension and layout planning
- Hands-on: Build a 3-line spread mooring system for a turret-moored FPSO
Environmental Conditions and Load Cases
- Wave, wind, and current profiles
- Directionality and spectral definitions (JONSWAP, Pierson-Moskowitz)
- Static vs dynamic loading
- Multi-discipline inputs and load combinations
- Hands-on: Apply wave and current environment to riser and mooring model
Time-Domain Dynamic Analysis
- Time history simulations: step-by-step workflow
- Integration settings and convergence
- Monitoring points and time series output
- Response analysis (displacement, tension, bending moment, fatigue)
- Hands-on: Analyze riser response in irregular sea state
Floating Body Modeling and Vessel Motions
- Importing vessel RAOs or defining 6DOF motion
- Vessel surge, sway, heave, pitch, roll, yaw
- Vessel offset and mooring/riser interaction
- Hands-on: Link vessel motion to mooring/riser system
VIV, Fatigue, and Clearance Checks
- Overview of vortex-induced vibration (VIV)
- Fatigue damage estimation (S-N curve, damage accumulation)
- Clashing and clearance criteria for multiple risers/umbilicals
- Use of line contact and clashing tools in OrcaFlex
- Hands-on: Perform clearance check and VIV screening for riser array
Advanced Features and Optimization
- Automation using Python/OrcaFlex API
- OrcaWave integration for hydrodynamic coefficients
- Line failure modeling and emergency scenarios
- Optimization of line profile and vessel offset window
- Hands-on: Batch run simulations and automate report extraction
Case Study and Capstone Project
- Deepwater riser/mooring system case study
- Participants complete full simulation from scratch
- Design basis, model build, run analysis, interpret results
- Compare performance under different environmental directions
- Present results and receive feedback