Structural maintenance of Agip platforms

摘要

In the recent past, Agip has tried to change from offshore maintenance management linked to limited knowhow and experience to the use of rational criteria which optimise the use of the available economic resources and which are sustainable with regard to the main international recommendations. At the same time, tools have become available which improve maintenance operations in terms of efficiency and reliability. In the near future, technological prospects indicate a wider use of ROV systems for inspections, thus increasing the range of possible operations in diverless conditions. The will mean that costs, linked mainly to the use of deep sea divers, may be cut. An example of this is the Flooded Member Detection (FMD) examination, carried out using ROVs able to evaluate, using gamma rays, the presence of water inside the platform braces and therefore establish if there are any through cracks or not. This system is now being used more frequently in the North Sea with the approval of Lloyd's Register, and in the Mediterranean it is used for the Vega platform. Another sector which can be improved is that of continuous monitoring of structures. This technology makes it possible to establish the presence of cracks and evaluate their extension by recording acoustic emissions produced during storms. From a more strictly design viewpoint, reliability curves are being processed for more critical components as a function of time (Figures 3 and 4), in order to optimise inspection planning and make the results usable for Bayesian type updating.