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DECOMMISSIONING AND BROWNFIELD SITES

DECOMMISSIONING

LMC occupies a unique position in the marketplace due to its considerable experience in the decommissioning of the North Sea Ekofisk complex as part of the industry’s largest decommissioning project to date and also the removal of the topsides of NW Hutton, the single largest steel platform to be removed, both of which were performed as part of a Frame Agreement with Heerema.

Expertise

For these projects, typical scope included:

  • Platform hook-down and removal surveys
  • Prepare Make-safe plans (more for very old/long-abandoned platforms)
  • Perform weight reconciliation checks (to determine current vs designed weight and CoG data)
  • Determination of cut locations and removal sequence planning
  • Prepare 3-D models
  • Prepare hook down scope and identify locations for splice severance (cables/pipes/offshore structural joints)
  • Recommend cut methods (flame/diamond-wire/abrasive jet etc.)
  • Design lift-off guides and barge/vessel set-down guides
  • Design all rigging, including rigging platforms, spreader bars etc.
  • Perform module global structural integrity checks
  • Perform local lift point design checks or new designs where required
  • Preparation of detailed offshore work packs / work instructions
  • Design grillage/sea fastenings
  • Perform barge motions assessments & bollard pull calculations
  • Prepare detailed offshore work packs and master equipment lists
  • Prepare offshore removal and transportation manual
  • Perform load-in/load-off engineering at disposal site

BROWNFIELD SITES

The tendency in some areas to upgrade older facilities to enhance production or provide flexibility for expansion has led to an increase in “Brownfield” construction.

Expertise

LMC have had detailed involvement in the following types of operation:

  • Retrofit of hang-off modules (up to 1000mt in weight)
  • Retrofit of hang-off modules (up to 1000mt in weight)
  • Drill Rig change-outs
  • Flare tip replacements

For this type of project, the following activities are also often undertaken:

  • Initial feasibility studies
  • Concept or detailed design of hang-off systems
  • Concept or detailed design of bumpers/guides
  • Concept or detailed design of any specialise winching/transfer systems
  • Anchor clash/interference studies with existing field infrastructure
  • Construction vessel mooring analysis

Work is performed under the very rigorous LOLER guidelines or under project-specific client requirements.