Built in record time
TEXT: IRINA LEE
The spectacular construction process started on 2 September in Kloster fjord in the district of Sunnhordland. The work was compared to attaching “giant Lego bricks” together.
“This is the largest operation to have taken place in inshore waters in Norway”, comments the project director for the Johan Sverdrup platform, Stig Jessen, from Aibel.
At the limit
What made this operation particularly demanding was the enormous weights involved.
“The biggest section weighed 10,300 tonnes. This is at the limit of what it is possible to lift”, explains Stig Jessen.
The maximum weight that can be lifted by the crane vessel from Heerema Marine Contractors (HMC) that was hired in to do the job is 11,000 tonnes.
“The conditions had to be perfect. HMC therefore had to spend time looking for a suitable location to carry out the operation. Kloster fjord was chosen because it is sheltered from the wind, which is an important factor. In addition, there is not much shipping traffic in the area”, comments Stig Jessen.
The second module that was lifted into place weighed 8,000 tonnes, with the third weighing 3,000 tonnes.
“Given the height in combination with the weight, it was absolutely at the limit of what the crane vessel could manage, but the operation was well planned and we were in total control”, comments Stig Jessen.
Three different yards
The work was scheduled to take seven days but was instead already completed on 4 September.
“Given that everything took much less time than anticipated, the 140 invited guests were lucky to see anything at all! We could actually have finished by the time they arrived. Everything was done in record time and was completed by Monday evening”, comments Stig with a laugh.
The modules for the platform deck of the Johan Sverdrup platform were produced in three different yards: at Aibel’s yards in Haugesund and Thailand, and at Nymo’s yard in Grimstad. This added to the suspense due to the question of whether the three modules would fit together properly.
“The maximum tolerance was a few millimetres, and we managed to stay within these margins. We therefore joined the first modules together very efficiently, which meant we were able to start the second lifting phase sooner than anticipated”, comments Stig Jessen.
Stig takes the opportunity to praise Aibel’s Marine Operation Manager Anne Kindlihagen, who had been planning the operation for 2.5 years.
“Anne and her team deserve a lot of the credit for this being such a success, along with our structures department in Asker and HMC, who were responsible for the lifting”, comments Stig Jessen.
The whole article is available in the Ferd Magazine (in Norwegian)