In 1996, the first step to assess fatigue in the hulls of FPSOs by monitoring was started when the FPSO Integrity Joint Industry Project was launched. Almost 20 years later, fatigue is now assessed on board FPSOs with advanced hull monitoring systems with automatic and extensive data analyses. Pieter Aalberts,

Hull integrity assessment of FPSOs for 20 years!

A fatigue assessment of an FPSO comprises multiple calculations and requires different input data such as the environmental condi- tions. However, uncertainties associated with these calculations make a fatigue assessment difficult and this is the reason why so many FPSOs are still suffering fatigue damage. By monitoring, the uncertainties are reduced and the fatigue integrity improved for both the present FPSOs and for future designs.

The original FPSO Integrity JIP examined the accuracy and validity of computational methods and as part of the scope of work the Glas Dowr FPSO, operated by Bluewater, was instrumented extensively.

Within the FPSO Integrity project validation of the design tools was done in the office,

which required a considerable amount of time and data processing capabilities. Operators needed a hull monitoring system with automatic data processing and data interpretation tools.

A decade on, the JIP Monitas was initiated. This aimed to develop an Advisory Hull Monitoring System that not only shows the FPSO’s lifetime consumption but also explains potential deviations from design predictions. Within the JIP the system was installed and successfully validated for both the Glas Dowr FPSO and the USAN FPSO (TOTAL). During the project contract awards were received

for the delivery of two more systems, show- ing that the system is being recognised by the industry.

In order to provide ‘Monitas related’ ser- vices to the industry, a Monitoring Advisory Systems group for offshore floating structures was initiated this year. The group aims to develop the added value of advisory moni- toring systems for integrity management by the correlation of measurements, exchanging experience and by providing software up- dates, support and training. Activities include the analyses of tool accuracy factors ob- tained from different floaters and the further development of the AHMS software, with for example, the backward prediction module for existing floaters. The Monitas Group would also welcome new participants.




Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24