Scope of Work: Onshore and offshore preparatory works, removal and disposal works
Location: Southern North Sea, UK
Client: Perenco U.K.
Main Contractor: Thames JV (Scaldis Salvage & Marine Contractors N.V. – Boskalis Offshore Marine Contractors B.V.)
Period: Q1 2015 – Q1 2018
Scaldis had already proven itself in the decommissioning market by removing several platforms in the past (REM island, Welland, Camelot, Draugen, K10-B). But in 2015 they encountered their biggest challenge in decommissioning so far: the complete removal of the THAMES A platform from PERENCO.
The Thames platform complex from PERENCO, consisted out of 3 platforms: a wellhead platform (AW), an accommodation and processing platform (AP) and a riser platform (AR). The removal of the AW template, conductors including inner casings had to be executed as well as their severance at -3m to the mud line.
A joint venture has been raised together with Boskalis to bundle forces and issue an attractive project execution schedule.
One of the advantages and became the key to success was the use of the middle class capacity Heavy Lift Vessel Rambiz.
These Heavy Lift Vessels are very cost efficient. By cutting the main (and heaviest) platform into two section, the total hook load did remain in the capacity of the Rambiz.
Onshore preparation phase, consisting of the preparation of the necessary method statements.
Offshore preparation phase, consisting of preparing the different platform parts to be removed.
Offshore heavy lift phase, consisting of lifting away the prepared platform parts and bring them a shore by transport barge or in the crane hooks.
Disposal phase at the disposal yard.