Project Overview
MMA was contracted by Allseas for the provision of grouting services and grout material on two drilling platforms that are to be decommissioned on the UK Continental Shelf. In June 2021, offshore services firm Allseas removed the former DP3 gas production topsides from Spirit Energy’s Morecambe Bay development in the East Irish Sea, using the giant Pioneering Spirit vessel. This follows the removal of the adjacent DP4 topsides and subsequent transport to the UK last year.
MMA's Solution
One of the key challenges associated with removing ageing infrastructure is lifting corroded steel structures safely and effectively. MMA’s solution was to grout clamps that were to act as lift points for the decommissioning vessel to engage with. Each platform had five of these installed at cellar deck level that could then be grouted from the platform deck.
Outcome
This is a novel approach, and the first time this type of application has been used on a commercial project. The benefits of a grouted solution mean less offshore time to fit the lift point and greater redundancy for fabrication tolerances. The grouted solution delivered by MMA effectively distributed the loads evenly into the ageing structure, reducing the amount of offshore time to fit the lift points, and providing greater redundancy for fabrication tolerances.
Technical Details
SikaGrout® 3620
- Certified for grouted connection by DNVGL-ST-C502
- High early strength development at low temperatures
- Low shrinkage
- No thermal cracking
- Max aggregate size of 1mm
Key Equipment / Installation Method
We used our Super Pan Mixer to batch and pump the grout into pre-installed clamps on the cellar decks of the topside.
MMA Innovation / Value Added
MMA and Sika collaborated to provide an ultra-high strength grouted under deck strengthening, which reduces the installation time and effectively spreads the high removal loads into the ageing structure. This increases safety margins and provides extremely robust lift points for the Pioneering Spirit to engage with.