Abstract

The mean time to failure of most permanently installed FPSO mooring systems is 7.6 years, in spite of design lives of 3 times that. This paper will combine an introduction to, and identification of, mechanisms that are deemed unique to floating production systems. For the purpose of this paper these have been classified into two categories:

Mechanical Deteriorative Mechanisms;

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    Sea floor trenching

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    Chain Wear

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    Turret Hawser Tube/Bending Shoe/Fairlead Issues

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    Out of Plane Bending

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    Differential loading

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    Fairlead/chain run-out

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    Vortex Induced vibration

Biological Deteriorative Mechanisms;

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    Sulphur Reducing Bacteria (SRB) in the water column, hawser tube and in sea-floor material. Identification of SRB related pitting that can lead to crack propagation within individual chain links

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    Microbially Induced Corrosion caused by specific interactions between sea floor mooring system and water temperature

The presentation will include:

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    An examination of deteriorative mechanisms using photographic, graphic and video evidence.

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    A brief overview of the classification and legislative requirements for permanent floating production mooring systems

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    An overview of the measurement and inspection techniques available in the industry

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    An overview of industry best practice guidelines for Mooring Integrity Management

Keywords:
offshore technology conference, upstream oil & gas, hawser tube, deteriorative mechanism, corroded chain link, general visual inspection, inspection, mooring system, marine growth, chain link
Subjects:
Offshore Facilities and Subsea Systems, Mooring systems
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2011. Offshore Technology Conference
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