Siri Platform Repair
Project: Siri Caisson Permanent Repair
Location: North Sea - Danish Sector
Client: DONG E&P A/S
Core Service: Consultancy and Project Support
Key Activity: Project Support
Duration: 30 Months
Siri platform with all clamps and cable stays installed and tensioned
Lower anchor clamps on support vessel prior to installation on Siri
Upper anchor clamps being installed on Siri legs
2 - 3
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Project Synopsis:
The Siri Platform is located in block 5604 / 20 in the north-western part of the Danish sector of the North Sea. The Siri platform is a MOPUSTOR self-installing design which started production in 1999, and has an expected lifetime to 2020. Production at the Siri Field stopped in August 2009 due to cracks in a subsea structure joined to the oil storage tank underneath the Siri platform.
A temporary seabed support was installed in January 2010, after which production resumed.
Since 2010 DONG E&P has been implementing a permanent repair of the Siri platform, which originally constituted of major structural installations to be executed in two installation phases.
CWS Solution and Scope Services:
CWS were approached in March 2012 by DONG E&P with an initial brief to review the repair strategy and implementation plan. This work was completed in May 2012 where upon CWS were commissioned to provide ongoing construction support through to project completion.
In December 2012 CWS completed a further project review with the objective of seeking alternative strategies to the existing two phase approach; this review was completed in 2012 and contributed to DONG E&P's decision in February 2013 to re-schedule the phase 1 activities, the suspension of the phase 2 works, and converting the temporary seabed support to a permanent part of the installation.
The phase 1 repair activities comprised of six structural clamps and cable stays and was completed successfully in July 2014 in line with the revised project schedule.
The cable stays have now resulted in a modification of the platform natural frequency which will, in combination with the now permanent seabed support, alleviate the structural issues and allow the original lifetime of the installation to be maintained.
CWS are proud to have participated in this novel and prestigious project and look forward to applying some of the unique lessons learned in other projects.
The scope of supply included:
review of project technical solution and implementation plan, support teams for all fabrication activities in the UK and continental Europe, alternative solution review study and provision of dedicated Facilities Manager for the permanent works fabrication elements.
