Client: Leading international energy company
Industry: Oil & Gas
Asset: FSU
Location: Norwegian Continental Shelf (NCS)
Year: 2019

Challenge

Thrusters are part of vessels’ positioning systems, which are required to keep vessels in station either by heading control or Dynamic Positioning (DP).

At times, clients may require urgent replacement of thruster(s). In one particular example, a client required an urgent replacement of one of the thrusters on its FSU, due to a leaking shaft bearing. It was urgent as it was necessary to continue operating within safe environmental limits with an intact dynamic positioning system.

However, there was no documentation on the lifting equipment. Moreover, the thruster was not designed for dismantling in accordance with best practices and standards on the NCS. The asset could also not be taken off hire nor disconnected from the turret.

The client thus contracted Axess Group to perform the thruster replacement, as we have experience doing so offshore.

Solution

As the particular FSU did not have a spare thruster, the old thruster had to be sent onshore to be refurbished. Axess acted as a bridge, connecting all the involved parties, and planned the various aspects necessary for project success, including logistics, design and procurement. In addition, using the tailor-made winches from our subsidiary, Alpa, the engineering team performed the lifting operation to replace the thruster offshore, while the asset was still in operation.

For this project, Axess utilised an in-house designed tool for handling the thruster. This removed the need for divers, who are typically used in this type of operation. The tool, designed according to NORSOK Standard R-002 Lifting Equipment, was remotely controlled by the engineers.

“We have carried out numerous thruster replacements offshore throughout the past 15 years for various types of vessels worldwide, including Europe and Asia-Pacific. We gain experience from each project to devise new methods and execute future projects more efficiently,” Tone Tomassen, Director of Sales, NCS said.

Results

Axess completed the thruster replacement on time, before the arrival of the winter season, thus avoiding the harsher environment. As the operation was carried out offshore, it helped the client to save time and costs. Furthermore, the removal of divers from the operation helped to enhance safety.

“Out of all the thruster replacement projects we have done so far, this project had one of the greatest number of both technical and planning challenges, which provided many learning points for our engineering team. We are proud to have completed this project successfully within the stipulated time frame and most importantly, safely,” Paal Thorsager, Project Manager said.

If you are interested in thruster replacements for your assets, please reach out to us.