Multi-Discipline Simulation

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CDS Simulation.pdf


CDS are using 3D simulation tools for Multidiscipline Multibody Dynamic Analysis of individual machines and systems. The software integrates mechanical components, pneumatics, electronics, hydraulics as well as control systems to enable virtual testing of prototypes that accurately account for the interactions between these subsystems.

These analysis are used to improve engineering efficiency and reduce product development cost by enabling early system-level testing. Systems and subsystems are validated against their specific requirements as part of the engineering process.

CDS capability includes:

- Multidiscipline simulation of subsystems on a machine, or on a complete machine, e.g. simulation of tension variation in a riser tensioning system
- Multidiscipline simulation of several machines working together, and installed on a offshore rig/ship having 6 degrees of freedoms, e.g. simulation of a Emergency Quick Disconnect of an Lower Marine Riser Package where a riser tensioner system, mechanical riser and a PLC controlled anti recoil systems needs to be verified.
- Bench marking of simulation models against real measured data.
- Import of flexible body into a Multidiscipline system, e.g. import of outer arm as a flexible body and intregrate that with the Multidiscipline system of the complete crane in order to verify that the position accuracy is within the requirements when the crane is used in Active Heave Compensation mode for landing critical components onto a subsea structure.

Riser Tensioner System is modelled in 3D with 6D freedom (heave, surge, sway, pitch, roll and yaw) were the mechanical part as riser joint, slip joint, flex joint, tensioner ring and wires are coupled to a detailed hydraulic model of cylinders, piping, valves and APV´s. Valves can be controlled manually and also respond to a logical sequence of incidents. A regulator for Anti-recoil mode is also included. All together mechanical system, hydraulic system and control system are combined in a state-of-art multi-discipline simulation for a riser tensioner system.

(Such a model gives valuble insight in behavior of the riser and tensioner system when stiffness of riser joint, stiffness of hydraulic system and pressure losses are combined for all possible rig motion from a real vessel (Heave, pitch, drift off etc). A simulation shows the feasibility of the mechanical and hydraulic design for a variety of cases of interest.)

Mechanical part:
-Riser Joints with wet and dry weight
-Slip Joint, Flex Joint, Tensioner ring
-Wire sheave

Hydraulic part:
-Cylinder (plunger, double acting)
-Piping with pressure losses
-Anti-Recoil Valve
-Hydraulic Isolation Valve
-Proportional Valve (Anti Recoil mode)
-Air valves

Control system:
-Logical Close/Open
-PID regulator
-Manually (triggered or after a time schedule)

System models:
-Wireline Riser Tensioners
-N-line/Direct Acting Tensioners
-Production Riser Tensioners
-CMC with active heave compensator
-Drillstring/Inline compensator
-Coil tubing combining tensioner system and compensator (CMC, Inline or DLC)
-TTRD combing tensioner system and compensator
-Dual Gradient Drilling with Tensioners
-Module Handling Compensator
-Heave Compensator for crane/winches
-Hoisting system with DeadLine Compensator (DLC)

Examples for the 3D dynamical simulation can be seen at Itisim website:



Riser Analysis


Download PDF:
CDS Simulation.pdf

Castor Drilling Solution provides Riser Analysis for better insight into the dynamics of riser systems and other load configuration connected to a dynamical vessel in a offshore environment.

The key objectives are to:

-Determine the range of operating conditions for a Vessel/Rig based on environmental data for a location
-Determine the feasibility of critical components for these operations




Global Riser Analysis


The Global Riser Analysis describes the operational limits for offshore operations in different environmental loads. These limits are found according to criteria described in API RP 16Q , ISO 13624 or similar recommended practice / standards. The global analysis is a FEA of the complete riser structure, and a dynamical riser model is built based on the actual riser joints for offshore operations, like Telescopic Joint, Upper/Lower Flex Joint, Bare Riser Joints, Riser Joints with buoyancy elements, LMRP and BOP.

Cases for the Riser Analysis are:

-Connected Drilling mode
-Connected Non-Drilling mode
-Deployment & Retrieval of BOP, supported in Gimbal/Spider and Derrick
-Hang-Off at Gimbal/Spider

Typical input data required for an analysis would be riser joints, riser configuration, vessel configuration/layout of tensioner, drillfloor and relevant equipment in derrick, vessel RAO data and environmental data for the offshore location.

The software used for the Riser Analysis will be Orcaflex. OrcaFlex ( is the world's leading software package for the design and analysis of a wide range of marine systems, including all types of:

-Riser systems: SCRs, TTRs, hybrids, flexibles, umbilicals, hoses.
-Mooring systems: spread, turret, SPM, jetty, etc.
-Installation planning with capabilities across the full range of scenarios.
-Towed systems: bundle dynamics, seismic arrays, towed bodies, etc.
-Defence, marine renewables, seabed stability and many other types of system.


Deployment & Retrieval Analysis


Several deployment and retrieval stages for the riser system are analysed for stresses and physical clearances. The riser is analysed for hangoff in drillfloor and the lifting equipment, typical a Top Drive in a Derrick structure. The images here show the Riser Running Tool delivered by CDS.


BOP Landing


The landing of the BOP and the complete riser stack on the wellhead is a critical operation where several systems are involved. The load of the riser stack is typical divided on the riser tensioning system, the top compensator, an active heave compensator and also the drawwork that lowers the riser stack.

The BOP Landing performance at different evironmental loads are analysed in a multi-discipline simulation of the 3D mechanical system, hydraulic system for tensioners and compensators, and the control system for the AHC.


Riser Disconnect - Recoil Analysis


CDS performs disconnect and recoil analysis to show the riser tensioning systems capability to lift the Riser Stack with the LMRP of the BOP in a controlled motion during a disconnect. The output is allowable riser tension settings and closing curves for the Riser Tensioners valves such that the LMRP do not fall back on the BOP/Wellhead and the Telescopic Joint is not collapsed at high speed or jump out of the Tensioner Ring.

The analysis is performed by 3D multi-body system model with full 6 degre of freedom for critical parts like the LMRP, Tensioner Ring and Telescopic Joint. Multi-discipline simulation is used for a detailed hydraulic model of pressure losses in tensioning system and discharge of mud column in riser.


Hard and Soft Hangoff


CDS performs dynamical analyses under storm environment and annual wave scattering where a disconnected riser stack is hung off in the Spider or supported by the tensioning system. The criteria is to have allowable stresses and clearances in a storm.

CDS also finds operational limits for a vessel/rig transit operation with supported riser stack for cases where other wells are nearby.


Riser Configuration Optimization


CDS builds a modular and easy configurational set-up for the riser analysis model. Several riser model configurations are picked from a library and simulated in batches for finding optimized configuration data for riser stack-up, locations, environmental loads, vessels and also vessel layouts.




Failure/Damage Analysis


Please contact us to find out how CDS can assist you in failure analysis and expert material investigation services.

CDS can provide Services such as:

  • Metallurgical Failure assessments
  • Wear and Corrosion mitigation
  • Cause & Origin Investigations
  • Component and material failure investigation
  • Comprehensive Failure Analysis
  • Cracking & Embrittlement
  • Documentation
  • Expert Witness
  • Engineering Tribology
  • Field testing projects
  • Guarantee claims
  • Polymer Degradation
  • Reverse engineering
  • Site examinations
  • Specification and procedure review


    Failure Analysis

    Fatigue failure:


    Corrosion failure:


    Coating failure:


    Expert advisory/consultancy

    • Metallurgical Failure assessments
    • Wear/Corrosion mitigation
    • Material/Coating selection
    • Validate Design and Operating conditions
    • Material testing



    Tribology/Corrosion Analysis

    CDS can provide Services such as:

    •Advisory on Material testing (Corrosion & Wear)
    •Pre-qualification of Components/Coatings
    •Realistic Multi-degradation testing
    •Validate Design for Operating conditions
    •Advice on Component Design
    •Material and Coating Selection
    •Tribo-Corrosion Analysis
    •Combined degradation testing
    •Test rig design/development
    •Engineering Tribology
    •Fitness for purpose studies
    •Lifetime assessment



    Mechanical Integrity Assessments

    Corrosion Analysis

    Electrochemical testing

    Component Pre-qualifications / Multi-degradation testing


    Combined degradation testing

    Ref. Node ART project

    Tribo-Corrosion Analysis:




    Wire Rope Endurance Analysis


    •Number of bending/loading cycles to wire rope breakage and discard versus the wire rope pull.
    •Calculated wire rope safety factor.
    •Recommended allowable discarding number of wire breaks.
    •Donandt-force (absolute limit of usable line pull for wire rope system).
    •Ton-cycle alarm setting at various operation scenarios.
    •Recommending optimal wire rope construction and sheave design.

    Lifetime Analysis of Wire Rope

    Number of bending or hoisting cycles to wire rope breakage or discarding vs. line pull
    (also fluctuating loads)


    Dynamic Tribology Simulation

    • Using Orcaflex simulation software to assist tribological analysis.
    • Feasibility study of cylinder sealing and support design at specific operating conditions.
    • Lifetime-, performance- and reliability assessments of large cylinder systems.