PetroSa Mossel Bay ECP project

The focus of the marine works study was to confirm the feasibility of the proposed technical solution for the installation of a new SPM facility for the import of condensate using the refurbished Oribi CALM buoy and a new 16” subsea pipeline which will connect the new CALM buoy to the existing 10” and 12” CBM pipelines via a new subsea manifold. Sufficient design development was carried out to support the preparation of a Class 3 estimate (20% to +30% accuracy) total installed cost estimate.

The marine scope of the feasibility study included the following activities:

  • Review of PFS and submissions from SPM buoy supplier
  • Specification, technical oversight and integration of marine survey and seismic campaign
  • Metocean modelling to determine site specific operational and extreme conditions
  • Design tanker analysis
  • Terminal throughput modelling
  • Facility siting assessment taking account of existing infrastructure and traffic in the bay
  • Full mission simulations for defining approach, sailing and emergency manoeuvres
  • Pipeline routing assessment and interconnection piping layout confirmation
  • On-bottom pipe stability analysis
  • PLEM and connection manifold design
  • Vessel traffic assessment, oil spill hydrodynamic modelling and oil spill response assessment
  • Development of a facility operation, maintenance and spares philosophy
  • Month-to-month uptime (availability) assessment
  • Pipeline installation and constructability assessment
  • Pipeline stringing yard siting exercise
  • Development of a level 3 implementation schedule
  • Capital cost estimate to accuracy of Class 3 (-20% to +30%)
  • Operational cost estimate to accuracy of Class 3 Class 3 (-20% to +30%)