The Adriatic Sea is scattered with steel platforms designed in the 70 /80's and most of these have already undergone a requalification process based on Structural Reliability Analysis (SRA).
As they approach decommissioning, benefits from advanced analyses decrease dramatically and annual inspections might be required to satisfy engineering and statutory demands; yet most of the inspection campaigns carried out in the last decade depicted a very healthy scenario for the Adriatic Sea offshore portfolio with the only exception of very rare cases.
The probabilistic approach to life extension can be enhanced by taking advantage of the progresses made in technology and data science over the last decades.
The idea is to first collect inspection and monitoring data across fields, "brush" them into a standardised format, in order to create a baseline representative of the current status of the offshore portfolio, identify structural KPIs and categorise assets archetypes in different classes. In a second phase chosen structures would be subject to combined metocean and structural monitoring, in particular strain and stresses of critical connections, that would provide data for the training of a machine learning algorithm that would expose a direct cause effect relationship between environmental loading and structural performance.
The information gathered would provide a valuable tool in the detection of anomalies and early indicators of structural degradation; furthermore an updated correlation model could be built on top of actual observations to extend structural warnings and considerations not just among the connections of the same structure but also between connections of similar structures.
Advanced SHM techniques are becoming more valuable as new technologies become more accessible in a race to drive down operational and maintenance costs.
The number of fixed platforms presently installed in the Adriatic Sea for oil or gas production nearing, or even exceeding, the end of their design life is increasing.
Fixed steel offshore platforms are typically designed with a target service life in the range of 20-25 years; according to that target, the corrosion and the fatigue issues, as well as the strength assessment against extreme environmental loads, such as the 100-yr extreme wave loading, are properly addressed at design stage.
