SS: FPSOs and Floating Production Systems: Implementation of the Monitas system for FPSOs
Authors: Kaminski Miroslaw Leck , Aalberts Pieter 
Published: July 2010

This paper is one of five papers presenting research results from the Monitas Joint Industry Project (JIP). The name Monitas stands for Monitoring Advisory System. The project has developed the Monitas system that presents, explains and advises on the fatigue lifetime consumption of FPSO hulls. The advice is based on comparisons between the design and the actual fatigue lifetimes predicted by replacing the design factors like operational settings, environmental conditions and hydro-structural response by the measured data. This paper specifies how to implement the Monitas system for FPSO units in the most effective way. This includes interfaces with other systems like the unit monitoring system and the environmental monitoring system. Requirements with respect to hardware and sensors typical for the Monitas system are given. The specification is illustrated by examples from present applications of the Monitas system, i.e. on board the Glas Dowr FPSO unit and the Usan FPSO unit.

Introduction

The background of the Monitas project is described by Kaminski (2007). After four years of research the project delivers a set of industrial documents and software for the Monitas system that presents, explains and advises on the fatigue lifetime consumption of FPSO's hulls. The advice is based on comparisons between the design and the actual fatigue lifetimes predicted by replacing the design factors like operational settings, environmental conditions and hydro-structural response by the measured ones. This is overviewed by L'Hostis et al., (2010). The application of the Monitas system for the Glas Dowr FPSO is reported by Aalberts et al., (2010). Hanson et al., (2010) and Takaoka et al., (2010) reveal details of the Monitas system regarding the wave measurements and the Fatigue Damage Sensor (FDS), respectively.

The project deliverables include, among others, a report on the Monitas methodology, the Monitas specification for installing the system onboard FPSO units, and the Monitas software (frame work) that can be tailored to any FPSO unit. The Monitas methodology explains how to design the system. This paper starts with explaining how the Monitas system is designed. After that the paper specifies hardware and sensors characteristic for the Monitas system. This is illustrated by examples from present applications of the Monitas system.

Definitions

In this paper, for the sake of simplicity, a company delivering the Monitas system will be referred as Vendor (abbreviated as " V??), and a company ordering the Monitas system will be referred to as Company (abbreviated as " C??). Examples of Companies are an offshore yard building a new FPSO unit or converting an existing tanker into an FPSO unit and an operator of an existing FPSO unit.

Design

As explained in the introduction, the Monitas system advices based on comparisons between the design and the actual fatigue lifetimes predicted by replacing the design data by the measured (actual) data. This means that first it has to be decided what, where and how has to be measured; i.e. the Monitas system has to be designed.