Photo: Thialf semi-submersible crane vessel (SSCV); Courtesy of Heerema Marine Contractors

Heerema’s Thialf removes topsides offshore Ireland – gallery

Dutch contractor Heerema Marine Contractors has completed another decommissioning activity related to a platform removal campaign for an offshore gas field in the Celtic Sea. The activities carried out by the company’s second largest semi-submersible crane vessel (SSCV), Thialf, included the removal of topsides for the Ireland-based PSE Kinsale Energy, a Petronas subsidiary.

Back in May 2022, the Irish Department of Transport informed within a marine notice that PSE Kinsale Energy confirmed the start of the Kinsale Head platform removal campaign was expected in late May. These activities were anticipated to run through to September 2022.

PSE Kinsale Energy ceased gas production at the Kinsale gas fields in July 2020 after 42 years of production due to depleting reserves. As part of the Kinsale area decommissioning campaign, which started in mid-April 2021 and was planned to run through to November 2021, the Stena Drilling-owned Stena Spey rig was set to head to its final location in October 2021.

Located some 50 kilometres offshore in the Celtic Sea, the Kinsale field consists of two steel platforms –  the Alpha platform in Block 49/16 and the Bravo platform in Block 48/20 – which were installed as part of the initial field development, commissioned in 1978.

As revealed at the time, the SSCV Thialf was selected to perform the removal of both platforms with the upper sections (topsides) of the platforms to be removed first, followed by the lower sections (jackets). The planned activities would involve several other vessels throughout the entire campaign, including two Heerema’s anchor handling vessels – MV Kolga and MW Bylgia – along with towing cargo barges H-541, H-407 and H-542.

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On 13 June 2022, Heerema disclosed that the removal of PSE Kinsale Energy’s Kinsale Bravo platform topside was completed, adding that it was working on the next step to remove the jacket. The topside was placed onto barge H-541, and after the removal of the jacket top section, the firm’s anchor handing tug MV Kolga was going to bring these structures for reuse and recycling.

Kinsale Bravo topside removed ✅ When decommissioning platforms, we take it one step at a time – first hookdown and…

Posted by Heerema Marine Contractors on Monday, June 13, 2022

The following month, on 4 July 2022, the company released a video showing the 3,600-metric-ton jacket being transported from barge H-541 onto the quayside at the Hoondert Services & Decommissioning (HSD) yard. At the time, Heerema also informed that its next step in this decommissioning campaign would be the load-in of the Kinsale Alpha topside and jacket top section, various accommodation modules, and the jacket bottom sections.

The PSE Kinsale Energy Ltd Bravo deck and topside have returned to shore! This short video shows the roughly 3,600 metric ton jacket being transported from barge H-541 onto the quayside at the Hoondert Services & Decommissioning (HSD) yard. To load in a structure like this, we must use ballasting to ensure everything is level and aligned with the quayside. This action was achieved by using both H-541’s internal ballasting system and Mammoet’s ballast pumps to displace a massive 25,000 cubic meters of water! Next will be the load-in of the Kinsale Alpha topside and jacket top section, various accommodation modules, and the jacket bottom sections. Once finished, the Kinsale platforms will be recycled around 97% ♻️ #makingtheimpossiblepossible #offshore #Heerema #KinsaleEnergy #recycling #sustainability #decommissioning #circularity

Posted by Heerema Marine Contractors on Monday, July 4, 2022

In an update from this week, Heerema informed that its Thialf vessel has now removed the Kinsale Alpha topside and its next step will be to transport the structure to the HDS yard in the Netherlands with its tug Bylgia and barge H-541 for reuse and recycling up to 97 per cent.

PSE Kinsale Energy also plans to remove all equipment from the Inch onshore terminal in 2022 and undertake additional work offshore to install protective rock covering over exposed ends of the pipelines and umbilicals which will be left in situ.

According to the Ireland-based firm, the final decommissioning activities will be completed before the end of 2022, marking the end of continuous operations in the Kinsale Head gas field.

When it comes to Heerema’s other recent activities, it is worth noting that the Dutch contractor’s Sleipnir vessel completed the removal and disposal of the Dunlin Alpha topsides in June 2022.