Decommissining Market

The topside of the Brent Bravo platform was removed from the sea by the Pioneering Spirit. (Photograph: Allseas)

EVER MORE WORK FROM THE DECOMMISSIONING MARKET

by Paul Schaap, PAS Publicaties

As more and more operators take the decision to remove their old offshore platforms from the sea, Dutch contractors are increasingly being called upon to take part in a whole raft of decommissioning projects. Clear leaders are Allseas and Heerema Marine Contractors (HMC). At the same time, Boskalis is also becoming more active in this new market segment. Uniquely designed special workboats are available to respond effectively to the new challenges from this sector. As in the market for offshore installation work, in the decommissioning market, too, boundaries are forever being pushed.

As in previous years, the single-lift installation/decommissioning and pipelay vessel Pioneering Spirit operated by Allseas once again attracted most attention in 2019, with a series of spectacular platform topside removals. This was certainly the case on 18 June, when the 25,000-tonne Brent Bravo topside was removed from the British Brent field in the North Sea. The single-lift removal of this giant topside took four hours, while the lift itself lasted only nine seconds. The Brent Bravo is the second of four topsides to be decommissioned and removed from the Brent oil and gas field, following on from the 24,200-tonne Brent Delta, in 2017. This topside was 125 metres tall and 70 metres wide. The Pioneering Spirit is now set to also remove the 15,000-tonne Brent Alpha topside and the 27,500-tonne Brent Charly topside from the Brent field, as well as the Brent Alpha jacket. The Brent Bravo topside was removed just a few days after the Pioneering Spirit had lifted the 3,800-tonne topside from the Valhall QP platform, in the Norwegian sector of the North Sea. This in fact was the first job undertaken by Allseas as part of the framework agreement with Aker BP. This single-lift operation lasted just two hours, with

the actual fast lift again taking just nine seconds. New decommissioning contracts for which Allseas intends to deploy the Pioneering Spirit include the removal for Equinor of the 48,000-tonne Statfjord A platform topside in the Norwegian sector and for CNR International, the topside of the Ninian Northern platform in the British sector of the North Sea. The Pioneering Spirit also plans to remove the 18,000-tonne topside and the 11,200-tonne jacket from the Gyda platform operated by Repsol Norge in the Norwegian sector of the North Sea. This contract includes an option for reinstallation, in another field.

Crane vessels

The semi-submersible crane vessel Thialf and the monohull crane vessel Aegir, both operated by Heerema Marine Contractors, were also hard at work in 2019 in the decommissioning sector. The Thialf, for example, was deployed for removal jobs in the Norwegian Ekofisk and Huldra fields. For its part, the Aegir installed a new jacket in the D12-B field in the Dutch sector of the North Sea, before removing the topside from the E18-A gas production platform. This same topside was moved around 80 kilometres, and then reinstalled on the previously placed, new D12-B jacket. The old E18-A jacket was then itself removed from the sea, and delivered to a scrapyard in Flushing.

One major decommissioning project in the Dutch sector of the North Sea involved the removal of the Kotter complex and the Logger complex, both operated by Wintershall Noordzee. This work was also undertaken by the Aegir. In a period of just ten weeks, the vessel removed a total of 15,000 tonnes of topsides and jackets from the sea, before transporting the scrap metal to Flushing, for demolition. Finally, HMC was responsible for removing the F3-FA gas production platform from the Dutch sector of the North Sea, on behalf of Centrica Energy.

HMC has signed new orders for decommissioning projects for the removal and disposal of the Dunlin Alpha topside from the British sector of the North Sea. This project requires the removal of 24,000 tonnes of topside modules. The work is due to be carried out in the period 20212024, in collaboration with AF Gruppen. Elsewhere, on behalf of Oceaneering International offshore Canada, a total of seven platforms will have to be removed from the sea off the coast of Canada, 200 kilometres east of Halifax, Nova Scotia. These platforms include both topsides and jackets belonging to operator ExxonMobil Canada. In May 2019, HMC, Offshore Decom and Decom Energy announced a collaboration for decommissioning projects, in a new company named Fairfield Decom. HMC’s latest fleet addition, the semi-submersible crane vessel Sleipnir, the largest of its kind in the world, will also be carrying out decommissioning work, in the Danish Tyra field and the British Brae field.

Relocation

One remarkable project was carried out in 2019 by SPT Offshore, in Malaysian waters. Within this project, the existing Ophir-A wellhead platform was relocated to the Jitang field. Using a huge floating sheerlegs, the platform, consisting of a topside and a jacket, was raised and transported to a new location in a onepiece lift, prior to reinstallation in the sea. In total, the operation took three days.

Platform sections from the F3-FA platform on board the Heerema barge H-405 following removal from the sea. (Photograph: PAS Publicaties)

An old E18-A jacket is seen here being delivered to the scrapyard in Flushing, by the Aegir. (Photograph: PAS Publicaties/maritimephoto.com)