Leading Role for the Decommissioning Market

Just like in the transport and installation of platforms and subsea installations for the offshore oil and gas industry, the Dutch offshore and dredging contractors are also playing a leading role in the emerging market for decommissioning and re-use. Most remarkable are the groundbreaking activities by Allseas, with the Pioneering Spirit. At the same time contractors like Heerema Marine Contractors, Seaway Heavy Lifting and Royal Boskalis Westminster are becoming other major players in this market.

Just like in 2016 the decommissioning activities of Allseas attracted most attention. After first removing the 13,500- tonne topsides from the Yme Mobile Offshore Production Unit (MOPU) in the Norwegian sector of the North Sea in August 2016, with the innovative single-lift installation/ decommissioning and pipeplaying vessel Pioneering Spirit, the next challenge came in 2017. This project saw the Pioneering Spirit deployed in the British sector of the North Sea to remove the 24,000-tonne topsides from Shell’s Brent Delta platform from the sea, for transportation to the Able yard in Teesside. In completing this project on 28 April

2017 the Pioneering Spirit set a new world lifting record. The Brent Delta platform was located 186 kilometres northeast of the Shetland Islands. The massive topsides were loaded onto the Allseas barge Iron Lady in the Tees Bay and subsequently transported to the Able yard towed by tugboats from Kotug.

The removal of the Brent Delta topsides is part of a larger contract according to which Allseas will be called upon over the next few years to remove a further three Brent topsides for Shell, varying in weight between 16,000

and 30,000 tonnes, as well as a jacket, all from the Brent field. Aker BP from Norway has also signed a long-term framework agreement with Allseas to remove from the sea the 36 year-old topsides and bridge from the Valhall QP living quarters platform in 2019.

Crane vessels Heerema Marine Contractors (HMC) has now successfully completed a whole series of dismantling projects. HMC attracted much attention last June with the successful removal of the large Murchison production platform from the British sector of the North Sea, far earlier than initially planned. The contract for this work had been signed by HMC and AF Offshore Decom, with CNR International UK in 2014. The contract was for the engineering, preparation, removal and disposal of the 24,000-tonne topsides and the 14,000-tonne jacket of the Murchison platform. The individual platform sections were lifted from the sea by the semi-submersible crane vessels Thialf and Hermod and transported to the home base of AF Offshore Decom in Vats, Norway.

A new project to be undertaken by HMC together with AF Offshore Decom involves the removal and disposal of four platforms connected to the Ekofisk field in the Norwegian sector of the North Sea. As part of this contract with ConocoPhillips Skandinavia, a total of around 36,000 tonnes of platform parts will be removed between 2017 and 2022. The platforms in question are the Ekofisk 2/4 H, Ekofisk 2/4 A, Ekofisk 2/4 FTP and Ekofisk 2/4 Q. This project is part of the Ekofisk 1 Cessation Plan. HMC has also been contracted over the next few years to dispose of seven old gas production platforms from five gas fields off the coast of Nova Scotia, as part of ExxonMobil Canada’s Sable Island Offshore Energy Project. Finally, on behalf of Maersk Oil, as part of the Tyra Development Project in the Danish sector of the North Sea, HMC will be removing 17,000 tonnes of platform units and bridges. For this project HMC has already signed an installation contract for new platforms. To carry out this work the brand new semi-submersible crane vessel Sleipnir will be deployed in 2019.

Seaway Heavy Lifting is also becoming an increasingly important player on the decommissioning market. This contractor was for example responsible for the removal from the sea of six platforms from Shell’s Indefatigable field. This work was undertaken by the crane vessels Oleg Strashnov and Stanislav Yudin.

Joint ventures Boskalis has been very active in the decommissioning market for several years. For this work, the Dutch dredging specialist operated a fleet of floating sheerlegs, that are regularly deployed for the offshore removal of old topsides and jackets. In recent years Boskalis has been cooperating closely with Scaldis Salvage & Marine Contractors from Antwerp, who operate the crane vessel Rambiz. Together these two companies have recently removed an impressive number of platforms from the southern section of the British sector of the North Sea and transported them to a scrapyard in Flushing. The removed platforms include the Horne and Wren satellites, the Vulcan and Viking satellites and the platforms from the Thames gas production complex. This complex consisted of a processing/quarters platform, a wellhead platform and a reception platform. Boskalis also plans to

deploy the dp crane vessel Bokalift 1, which is due to be launched later this year in the decommissioning market. The brand new heavy lifting vessel Gulliver operated by Scaldis Salvage & Marine Contractors will also be deployed for similar work.

Another joint venture that is very active in the decommissioning market is that between Peterson and Veolia, both of whom operate a series of dismantling facilities around the North Sea. In 2017, on behalf of Repsol Sinopec Resources UK, this joint venture started on the dismantling of the Buchan Alpha oil production vessel and together with Boskalis was responsible for the removal, transport and disposal of the Leman BH platform for Shell. The lifting and transport work was carried out using the floating sheerlegs Taklift 4. The platform was

located in the British sector of the North Sea and was transported to the new Peterson Veolia decommissioning base in Great Yarmouth.

National platform In October 2016 the national platform Nexstep was established for re-use and decommissioning activities in the Dutch sector of the North Sea. Nexstep is an initiative of Energie Beheer Nederland (EBN), representative of the Dutch state in all Dutch oil and gas projects, and NOGEPA, the industry body for oil and gas producers in the Netherlands. Nexstep was launched with the mission of serving as an inclusive and collaborative umbrella organisation that coordinates, facilitates and seeks dialogue on the re-use and decommissioning agenda for oil and gas infrastructure in the Netherlands n

The removal of the Brent Delta topsides by the Pioneering Spirit owned by Allseas. (Photograph: Allseas)

Transport of a platform section from the Thames gas processingcomplex. (Photograph: PAS Publicaties/maritimephoto.com)

Using the Rambiz, Boskalis and Scaldis have removed a whole series ofplatforms from the sea. (Photograph: PAS Publicaties/maritimephoto.com)