A major ME operator was running a pilot programme for conductor repair and engaged Nautec to carry out external conductor strengthening as part of a 9 well campaign.

The Scope

  • Process: Supervise erection of scaffolding around Conductor of well; Removal of grout and surface preparation of exposed steel rebar; external cleaning and inspection; installation of mould; grouting operation; removal of moulds after curing of grout; visual inspection and verification.
  • Supplies and Services: Supply of riggers to assist setting up of rigging equipment and other works; supply of moulds and reinforcements for external strengthening; supply of NaX® Q140 Ultra High Performance Cementitious (UHPC) mix, grouting spread, technicians and all necessary equipment and materials required for carrying out the grouting services; project management including Reporting and QA/ QC & HSE.

Challenges

  • The conductors in question were suffering from wall thinning and corrosion at MSL.
  • During inspection it was discovered that grout was missing from the conductor with steel rebars were exposed at EL -4.0 and EL -5.0. An attempt to solve the issue by using divers was rendered impractical, as the cavities of the grout had enlarged to the point where patching chemical and cover plate were unable to seal the cavities.

Solutions

  • Nautec approved a grouted repair, which was completely diverless and allowed for the full load of 87kips to be transferred across the weakened section of the conductor wall.
  • Nautec provided materials, equipment and personnel to execute in accordance with the engineering design to the satisfaction of the clients technical lead and the PMT.

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