The Tyra field is the largest gas field in the Danish North Sea sector. It is operated by Total and has been producing since 1984.
The Tyra East and West field centers are suffering from seabed subsidence, and mitigation projects have been in continual, progressive implementation for more than a decade to extend the field life as significant reserves remain to be produced from the Tyra field. The scope of work for the Tyra Future Brownfield project is to redevelop and rationalise the Tyra East and West facilities to enable economic production of the tail end production profile.
To extend the service life of wellhead platforms suffering from seabed subsidence, the existing topsides and bridges will be decommissioned and replaced by new topsides and bridges, which are elevated by an approximately 10 metres high module support frame (MSF) extension.
Ramboll was awarded the Tyra Future Brownfield project, which included the required engineering to enable removal of the existing Tyra East and West platforms and bridges.
The structural scope of work included lifting assessments and designs for removal of topsides and bridges. The work also included installation procedures and design of conductor support decks for temporary and final supports for both internal and external conductors.
The piping, mechanical, electrical and instrumentation scopes included the plans for disconnection of the topsides and bridge to be removed, as well as, the reconfiguration of the accommodation platform to function as a stand-alone platform during decommissioning activities.
Together with the client, Ramboll worked out the removal strategy and matured the concepts all the way to detailed engineering. Several innovative design- and installation solutions were devised to cater for the special situation where the removal of topsides still had to include considerations for installation of new ones and associated infrastructure.
Previous experience was imperative for the project
Ramboll’s experience with the Tyra field dates back more than 25 years. This experience from pre-FEED design work for the Tyra wellhead platforms and bridges came with an extensive knowledge package that added significant value to the project execution. The assignment concentrated on minimising offshore work and downtime, as well as planning as much preparatory work as possible.