Troll A is an impressive gas production platform located in the North Sea. It represents the pinnacle of the Norwegian condeep concept – movable deepwater concrete structures. In 2018, the Troll Phase 3 (TP3) development has been undertaken, which includes a subsea production system with two templates and a total of 8 wells located at the Troll West Gas Province (TWGP). The subsea production system will be producing into a 36″ pipeline, which will be tied back to Troll A. Bezemer was awarded the task of providing a linear winch for the pipeline pull-in of this project. 

Working with limited space and ATAX zone II standards 

The project presented several challenges, including the lack of space to position the storage winch behind the linear winch. Additionally, the crane on the work deck had a limited lifting capacity of 20 tonnes. All equipment with an assembled weight above this benchmark had to be taken apart for re-assembly after lifting on the deck. Moreover, the winch arrangement had to be installed at a Zone II, Gas group IIA, and Temp Class T3-rated deck. Therefore, all equipment is required to be certified to operate in these zones. 

To overcome these challenges, various wire sheaves were used to manoeuvre the pull wire from the J-pipe to the linear winch and storage winch. A dismountable winch and winch frame were used, along with a storage winch with an interchangeable drum. We used our KTC500 linear winch spread, which is fully compatible with the Zone II, Gas Group IIA, and Temp Class T3 requirements. 

Pulling through a J-Tube using a linear winch 

The work method involved sending a feeder wire from the deck through the J-pipe to a vessel and then hooking it up to the pull-in wire. The next step was to install the pull-in wire from the vessel to the linear winch and pull in the pipeline from the pipelaying vessel to the Platform Shaft. Finally, the pull-in wire was uninstalled.  

The results of this project were successful, and the TP3 pull-in was accomplished as planned. The safe and successful pull-in of the pipeline is a testament to the ingenuity and technical expertise of the teams involved in this project. The Troll A platform continues to provide a reliable source of gas for Norway and the world, making it a vital piece of infrastructure in the energy sector.