Aquaterra develop conductor stabilising system, achieving 80% cost savings

Project Summary

Lateral wave movement causes impact on conductors, caissons and risers initiating fatigue and fracturing which can be both costly, challenging and dangerous.

Existing shim-type solutions can be costly and, in some cases, unreliable and usually require replacement after a short period of time. NZTC supported Aquaterra to research and develop a simpler more cost-effective solution aimed at stabilising offshore caissons, risers and conductors, to reduce movement, increase guide stability and moderate vibrations – in the long-term extending their operational life.

The initial phase of the project developed and tested a cold poured urethane-based two component polyurethane system (including installation tests on a conductor restraint mock-up) that doesn’t require specialist equipment to install and be able to cure at low temperatures.

Industry value:
A typical shim programme costs approximately £50,000 per conductor. Using this innovative solution could result in 80% cost savings per conductor, due to the materials used, ease of installation and reduction in preparation and deployment time.

Key results:
The project was successful in identifying a suitable urethane material that is predicted to withstand the environmental loads, is easy to install using mechanical aids (a mould) and does not require specialist storage, handling, or application equipment. A significant added advantage of using this alternative material and simplified installation methodology is that a pre-job site survey is not normally required.

Lessons learned:
Results from the engineering study and workshop trials urethane performed better and made installation simpler and does not require specialist storage, handling, or application equipment. Field trials with industry partners will be undertaken to validate the technology.