In May 2015 Nautec completed the grouting works associated with the installation of the XANAB-B platform. Nautec’s batching system – a fully containerised, reduced footprint grouting spread – was mobilised on SAPURA’s SK3500 vessel to carry out the grouting works, which required the injection of 66 mT of NaX™ Q110 in 4 skirt pile sleeve annuli at a water depth of approximately -29.5m.
Nautec was commissioned by main contractor Sapura Mexicana, SapuraKencana’s wholly-owned subsidiary in Mexico. The project was completed for end client PEMEX, Mexico’s national Oil & Gas Company.
The scope of services comprised the provision of qualified offshore grouting personnel and project management including reporting and QA/QC & HSE; provision of offshore grouting equipment and High Performance Cementitious (HPC) grout NaX™Q110.
The grouting works was to be completed within a 1- day time window and at nearly -30m water depth. The requirements of the grout included a minimum 55 MPa long-term compressive strength (28-day strength) and a 24-hour (early) compressive strength of 27 MPa.
For the injection of the HPC grout into the jacket skirt piles, a series of flexible 2″ hose with camlock coupling end connections were used. The platform was preinstalled with a subsea grout line system comprising of 3 inlet manifolds. During operation, the quantity of grout pumped into the annuli was monitored and recorded. This included the number of HPC bags mixed, the volume of water used to mix, the time taken from start of mixing until completion of pumping (per bag), pressure readings and grout temperature. On-site compressive strength testing of cube samples taken for all sleeves was carried out in Nautec’s mobile offshore testing laboratory.