Non-stop structural frequency monitoring set to improve safety of North Sea platforms

Citation

(2001), "Non-stop structural frequency monitoring set to improve safety of North Sea platforms", Disaster Prevention and Management, Vol. 10 No. 5. https://doi.org/10.1108/dpm.2001.07310eab.003

Non-stop structural frequency monitoring set to improve safety of North Sea platforms

Non-stop structural frequency monitoring set to improve safety of North Sea platforms

EQE International, one of the world's leading technology-based risk-management consultancies, has launched a project to investigate which North Sea platforms are suitable for an innovative frequency monitoring technique that provides a round-the-clock check on their structural health. "Every offshore steel platform sways and twists under wave action with its own set of frequencies", says Dr Simon Thurlbeck, head of EQE's engineering division. "Damage to the structure, such as fatigue cracks, alters the structural stiffness and changes the platform motions – something which operators can now detect straight away if they continuously monitor platform movements." A group of North Sea platform operators has thus commissioned EQE and Fugro to assess the feasibility of using the sway-monitoring technique on 13 very different platforms. The joint-industry project is valued at £120,000. "Continuous remote monitoring is the best way of ensuring structural integrity", says Dr Thurlbeck. "It is cheaper and safer to implement than traditional periodic checks. It also reduces the chances of major damage occurring just after an inspection, which could massively increase the risk of a platform collapsing in a major storm." Structural surveys are currently carried out on platforms using divers or remotely operated vehicles. But with diver-support costs running up to £100,000 a day, such surveys are usually only done every two or three years. "Sway monitoring can detect damage immediately, allowing a repair to be quickly implemented and minimise the time a platform is exposed to increased risk," says Dr Thurlbeck. EQE will be looking in particular at the potential problem of using sway monitoring on older platforms, which tend to have much more complex designs with many more structural members. "The so-called 'structural redundancy' of older platforms means that failure of an individual structural member may have minimal impact on sway frequency and could be impossible to detect", says Dr Thurlbeck. "However, this may also mean that failure of a single member is less critical." Under a separate contract EQE is also investigating the feasibility of a new wireless sensor system for continuous remote monitoring. Designed by UK inventor Ronald Geary, the system has been awarded £50,000 development funding via the National Lottery.

For further information: Steve Lewis/Simon Thurlbeck. Tel: +44 (0)1925 287300.