Image: Molikpaq Project: Arctic drilling caisson bearing refit for high seismic area

Minerals & Metals1 min read

Molikpaq Project: Arctic drilling caisson bearing refit for high seismic area

Offshore Sakhalin Island, Russia
Sakhalin Energy Investment Company
2010 - 2017
Oil Sands; Gas

Originally designed by Ausenco in 1981 for Gulf Canada for use in Canadian Beaufort Sea, Molikpaq is now located off Sakhalin Island as the first oil production platform in the Russian Arctic. The Sea of Ohkotsk is ice-covered for half the year, generates severe waves during the open-water season and is one of the world’s most seismically active regions.

After assisting Sakhalin Energy Investment Company (SEIC) in re-deploying Molikpaq to Sakhalin, Ausenco continued its long-standing association with this platform by supporting SEIC in their upgrade and maintenance program.

Ausenco’s work over the last several years has focussed on changing the 59 aged seismic bearings between the Caisson substructure and Box Girder Deck (BGD) that supports the platform topsides. Ausenco assisted SEIC on the new Lead Rubble Bearing (LRB) design and performed detailed structural analysis for the BGD and Caisson integrity under the seismic load, jacking load and sagging load conditions. The DNV code check was also performed to establish the structural capacity during the jacking operations.

Scope of Work

  • structural analysis of the bearing replacement
  • technical support to the bearing design and procurement
  • technical support to jacking tendering and bid evaluation
  • development of procedures and tools for field execution
  • supervision of the on-site execution.

The tools and procedures developed by Ausenco enable the site engineer to make independent decisions based on the actual site loading condition without referring back to home office for analysis, which minimized possible delays to the construction progress. The project was completed ahead of schedule.