Nautec has completed its grouting services of the Goodwyn-A (GWA) Platform 4 Flare Tower Legs for which they were contracted by Australian oil and gas company Woodside Energy Ltd.

The work was carried out by pumping NaX® grout up 85 meters height using the conventional “bottom to top” methodology and it was executed from the platforms’ deck space.

This followed extensive engineering studies over the past 4 years where FEA analysis and trial model tests have been carried out. 


  • Woodside Energy Ltd.


Execution of infill grouting of GWA platform 4 Flare Tower Legs:

  • Set-up and demobilisation of grouting spread.
  • Grout hose routing from Module E to Flare tower leg inlet nozzle
  • Infill of NaX® Q140-R Ultra High Performance Cementitious grout into GWA platform 4 (each) Flare Tower legs up to EL + 127meters.


  • The installation and grouting services took place subsea at 77 – 82 meters water depths.
  • The small footprint spread was set up and the jacket grouting work carried out utilizing the Main Work Barge LTS3000.
  • The grouting team used the first generation Nautec ROV connector to install the grout inlet ports at EL (-) 28.6m on the jackets. The grout hose was attached to the ROV connector, which connected the inlet port to the Jacket leg.
  • The grouting team were required to undertake additional preparation for a General Purpose Alarm – Flooding of Equipment scenario. In this situation if a GPA was to be triggered on the platform, the grouting team were to secure the equipment and cease grouting works for up to 5 hours and then return to work after the emergency and commence grouting works. The grout material was designed to be able to stop pumping for up to 6 hours and restart in up to 50°C temperature conditions.


  • A pretest was carried out at the Nautec UHPC materials factory to prove the temperature and standby time. The performance of NaX® Q140-R was verified and witness by the client.
  • Strengthening of Goodwyn-A platform Flare Tower.
  • Method of strengthening applied was infill grouting, where NaX® Q140-R high strength grout was pumped internally into the base of each of the 4 legs up to a height of roughly EL+127m.
  • Completion of the 4 Flare Tower legs took a total of 4 days as planned.
  • Assistance with equipment demobilisation.
  • Provision of project management including Reporting and QA/ QC & HSE.

Client Benefits

  • NaX® Q140-R exhibit good flowability with high inherent cohesiveness and anti-washout property and can be easily pumped into structures with narrow constrictions such as grout trenches in connection with onshore wind turbines, filling of annulus in pipe-in-pipe systems or hollow sections, which are not easily accessible by conventional mortar or grout systems.
  • The materials’ dense nanostructure results into a series of unique mechanical behaviour such as extreme high compressive and flexural strength, up to 10 times stronger than normal concrete, and an E-modulus of more than 50 GPa.

Click here to download the project case history.