TOPSIDE INSTALLATION VESSEL

Objectif

The objective of the project is to develop the principal innovative parts of an installation vessel for topside units of fixed offshore platforms.
The innovative parts are :
- A system which compensates the wave induced vessel motions.
- Mechanical structures which are used to support the topside units.
- Construction of the vessel, which is of an unconventional shape.
VESSEL STRUCTURE
Structural engineering has led to estimates for the amount of new steel which is required for the construction of the vessel. MECHANICAL COMPONENTS
Initial designs of the main components which are part of the compensation as well as of the supporting structures of the topside unit, have been made. This work has established the feasibility of the construction.
FUNCTIONAL MODEL
Testing of the scale model of the motion compensation system demonstrated the feasibility of this system. It proved possible to reduce both the vertical and the horizontal motions of a topside unit gradually to zero, while no large forces between the topside unit and jacket were required.
MOTION COMPENSATION SYSTEM
The initial design of the layout of the hydraulic system, which forms the heart of this system, demonstrated that it is possible to realise the hydraulic system using existing components.
A computer simulation of the 3 dimensional motion behaviour of the vessel and the topside unit, incorporating the motion compensation system, yielded the values for the design parameters for the hydraulic cylinders and other main components.
The first part of the project is the evaluation of an optimal shape and construction type of the vessel. This will involve estimates of strength and stiffness of various vessel configurations and estimates of the amounts of steel required in each configuration
.
Once an optimum configuration has been chosen the main subsystems of the vessel have to be designed. This part of the project will result in a general arrangement of the vessel, together with detailed operating procedures.
Development of the motion compensation system forms the second part of the project. This system comprises a mechanical construction which allows the installation vessel to move relative to the topside unit, together with a set of hydraulic actuators which are controlled in such a way as to hold the topside unit stationary while the vessel oscillates due to wind and waves. A functional model of this system is being constructed. The model will contain all functions of the final system. The model will be used to test various control strategies for the hydraulic actuators and to test the effects of failure of selected subsystems. The model will further be used to validate a computer program which simulates the dynamic response of the system.
Further parts of the development of this compensation system are the evaluation and selection of sensors and monitoring systems, which provide the required data to the control system's the development of control algorithms and the selection of electronic and hydraulic components.
As the topside unit is lifted in an unconventional way, the mechanical components of this system have to be newly developed.
These components comprise :
- Large floating bodies which provide the lifting force to lift the topside unit, together with a system which guides the motion of these floaters.
- Ball joints for large weights
- Lifting frames for the topside unit.

Programme(s)

ENG-HYDROCARB 2C - Programme (EEC) of support for technological development in the hydrocarbons sector, 1986-1989

Thème(s)

1.1 - AUXILIARY SHIPS AND SUBMERSIBLES

Appel à propositions

Data not available

Régime de financement

DEM - Demonstration contracts

Coordinateur

ALLSEAS ENGINEERING BV

Contribution de l’UE

Aucune donnée

Adresse

R. J. SCHIMMELPENNINCKLAAN 1
2517 JN THE HAGUE
Pays-Bas

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