In December 2016 Nautec completed the pile grouting work associated with the installation of a supplementary structure to support the existing XANAB-A platform located in the Litoral field, in the Gulf of Mexico. Nautec’s batching system – a fully containerised, reduced footprint grouting spread – was mobilised on DIAVAZ’s Atlantic Challenger vessel to carry out the grouting works, which required the injection of 15 mT of NaX® Q110 in 2 skirt pile sleeve annuli at a water depth of approximately -30 m.

The Client

  • Nautec was commissioned by Constructora Subacuática Diavaz S.A. de C.V. (Diavaz)
  • The project was completed for the end client PEMEX, Mexico’s national Oil & Gas Company

The Scope

  • The provision of qualified offshore grouting personnel
  • Project management including reporting and QA/QC & HSE
  • Provision of offshore grouting equipment and High Performance Cementitious (HPC) grout NaX® Q110

The Challenges

  • 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 80 MPa long-term compressive strength (28-day strength) and a 24-hour (early) compressive strength of 50 MPa
  • Grout plugs were set prior to filling the 2 skirt pile sleeve annuli

The Services

  • For the injection of the HPC grout into the jacket skirt piles, a series of flexible 2” hoses with camlock coupling end connections were used
  • The supplementary platform was preinstalled with a fixed grout line system
  • Prior to the structure load-out, Nautec pre-installed its subsea grouting ports to facilitate the grouting operations
  • 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 early compressive strength testing of cube samples taken for all sleeves was carried out in Nautec’s mobile offshore testing laboratory
  • 3-day, 7-day and 28-day cube samples were sent to a third party onshore laboratory

Client Benefit

  • The installation work was carried out using NaX® Premix System; a proprietary grout range developed by Nautec.
  • NaX® Premix System is designed as a ready-to-use cement-based dry blended powder formulation. The addition of a prescribed amount of potable water produces cohesive and flowable non-shrink grouts that develop high early-age strength and are impermeable to water ingress.
  • The versatility of the NaX® Premix System allows for specific client’s requirements to be met.

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