Carra, C., Wales, S., Gumley, J., Jobson, B., McDonnell, S., and Mir, U., Paper Number OTC-25418, Proceedings of Offshore Technology Conference OTC), Houston, Texas, USA, 2014.

Abstract

Integrity management has been gaining much interest in the last couple of years as focus has shifted towards remediation and life extension of assets. This paper will look at the operational issues surrounding the management of an FPSO with a degrading mooring system with multiple adjacent line degradation. The paper will discuss the importance of effective day-to-day integrity management through a regime of coordinated metocean forecasting, metocean monitoring, FPSO position monitoring, numerical modelling and ongoing inspection. 

Applicable to a wide range of operating floating production systems as well as to the design and development of sound integrity management practices for all new systems. 

The paper will provide examples of: numerical modelling and verification of system performance based on observed and forecast metocean conditions; the correlation of the numerical predictions against measured vessel offsets; the importance of time-domain and spectral response comparisons; the determination of limiting sea states for continued operations; the determination of system response characteristics under different mooring system failure scenarios; and the interpretation of mooring system condition based on measured system behaviour. The paper will also discuss issues related to system monitoring, inspection strategies and emergency response planning. 

This paper presents significant contributions to the effective management of mooring system integrity through: (a) demonstration of the means by which numerical models can be verified against actual system mooring behaviour (b) demonstration of the importance of coordinated metocean forecasting, in-field metocean measurement, FPSO position monitoring and system response prediction to effective day-to-day operations (c) demonstration of the importance of scenario modelling of potential mooring system failures modes to provide the Facility OIM with the ability to make timely decisions based on the observed system behaviour.

 

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