Tyra's Resurgence: Breathing New Life into Denmark's Gas Giant

Tyra is Denmark's largest gas field, with its infrastructure also serving as a processing hub for other nearby gas fields, processing and exporting more than 90% of the natural gas produced in the Danish North Sea.

A couple of years ago, the field, which had been in production since 1984 was on the verge of being decommissioned as its facilities had been nearing the end of life, and its jacket-supported platforms were slowly sinking ever closer to the sea surface.

In 2017, then-operator Maersk Oil said the facilities were no longer safe for work, having sunk five meters deep over the years, and warned it would shut down the field for good on October 1, 2018, should no viable economic solution for the development of the field be found, putting in jeopardy hundreds of jobs, as well as other nearby fields.

A couple of months later, a decision was reached to redevelop the field, by removing old infrastructure and installing new jackets and platforms, not a simple undertaking, in what would become Denmark's largest infrastructure project, as well as Denmark's largest recycling project.

Namely, the redevelopment called for the field shutdown in 2019, removal and decommissioning of the prior Tyra platforms, some reuse, recycling, and 10-13 meters extension of the current jackets at six platforms that would have new topsides a totally new process platform, and a new accommodation platform.

According to the main decommissioning and removal contractors for the project, Allseas and Heerema Marine Contractors, the equivalent of multiple Eiffel towers in weight of Tyra infrastructure had to be removed and taken to shore for recycling, to make way for new infrastructure, also weighing tens of thousands of tons.

A lot has happened since the decision to proceed with the redevelopment of the Tyra field, located, in Blocks 5504/11 and 12, 225km west of Esbjerg, was made. Some companies no longer exist today, some have sold their interests in the project, and some have been renamed, and the production start-up deadline had to be postponed due to the COVID-19 outbreak.

Maersk Oil was bought from Maersk by France’s Total in a deal estimated at $7.45 billion, struck in 2017 and completed in March 2018.

In September of the same year, the French oil major bought out Chevron’s Danish business, increasing its operatorship in the DUC from 31.2% to 43.2%. In October 2018, Shell agreed to sell its Danish upstream business to Norwegian Energy Company (Noreco) in a deal valuing Shell’s assets at around $1.9 billion. In May 2021, Total changed its name to TotalEnergies to mark „strategic transformation into a broad energy company,“ and in March 2023, Noreco announced its name change and is now known as BlueNord.

Sembcorp Marine which in December 2019 secured the subcontract to construct six topside modules and four bridges for the Tyra Redevelopment, is now called Seatrium, after completing its $3.4 acquisition of Keppel's offshore & marine unit.

Today, TotalEnergies is the operator of the Tyra field on behalf of Danish Underground Consortium (DUC) – a partnership between TotalEnergies (43.2%), BluNord (36.8%) and Nordsøfonden (20%).

Removals

In July 2020, Heerema's giant LNG-powered semi-submersible crane Sleopnir vessel, equipped with a pair of revolving cranes that can lift 20,000 tonnes in tandem wrapped up the first phase of the Tyra decommissioning when the topsides, including wellhead and riser platforms, were removed.

The second phase of the decommissioning campaign consisted of two main lifts of the two integrated accommodation and processing platforms at Tyra East and Tyra West.

Allseas’ giant catamaran Pioneering Spirit was employed for this part of the campaign, removing both topsides in single lifts.

The 14,000-tonne TEA topsides and 7,800-tonne TWA topsides were removed with the vessel’s motion-compensated topsides lift system. For the smaller, lighter structures, the vessel’s then newly aft-mounted 5000 t.

In September 2022, Allseas’ Pioneering Spirit removed two more offshore jackets from the field and sent them for recycling. The removal of the two jackets concluded Allseas involvement in the Tyra Redevelopment Project.

Allseas’ role in the redevelopment project covered engineering, preparation, removal, transportation, load-in to shore, and recycling of the Tyra East Alpha (TEA) and Tyra West Alpha (TWA) topsides and jackets, integrated production facilities (IPF) module, two flare jackets, and monopile.

In total, Pioneering Spirit removed more than 35,000 tonnes of offshore facilities from the field.

All in all, 50,000 metric tons of material were removed, which according to TotalEnergies, is the equivalent of seven Eiffel Towers.

Installation

Heerema Marine Contractors' Sleipnir semi-submersible crane vessel in September 2020 installed two new Dragados Offshore-built jackets, which formed the foundation for the new Tyra process and accommodation platforms.

The two jackets were the first new jacket structures delivered and installed for the Tyra redevelopment project.

The vessel then also installed the remaining new Tyra II modules including the Rosetti Marino-built accommodation module, six wellhead and riser modules, and four bridges in September 2021 and April 2022.

In early October 2022, Heerema Marine Contractors installed the TEG module, described as the biggest Tyra II project topside, on the last remaining bare jacket at the Tyra offshore field.

Heerema said that it had broken a world lifting record with the installation of a 17,000 metric ton, 47-meter-tall, Tyra TEG module. Heerema’s Sleipnir lifted the giant module from the heavy transport vessel GPO Emerald, sailed one nautical mile to the pre-installed jacket in the North Sea, raised the module by nine meters, and then lowered it onto the six legs.

The processing module will, at peak, be able to process 300 million standard cubic feet of gas per day, which comes from both Tyra and five unmanned satellite fields, namely Tyra Southeast, Harald, Valdemar, Svend, and Roar.

On October 10, 2022, TotalEnergies said it had completed the offshore installation works at the project, with Heerema's Sleipnir setting down an 85.4-meter-long bridge between the new Tyra II processing platform and the accommodation platform.

“Now all dots of Tyra II are connected and lifting the final four Tyra II pieces – the process module, two bridges, and a flare tower – comes to a successful end." TotalEnergies said at the time.

Recycling

As previously mentioned, Tyra has also become Denmark's largest recycling project for offshore installations.

In December 2022, Total said that all the old platforms and structures removed from the Tyra field had been 98.5% reused and recycled.

M.A.R.S. yard at the Port of Frederikshavn was responsible for the recycling at its 290,000 m2 recycling area, which has been described as the world’s first recycling facility built to recycle jack-up rigs, ships, and offshore platforms.

Production

Noreco, now known as BlueNord, TotalEnergies' partner in the project, said in November 2020, that the start-up of the Tyra Redevelopment was expected in the second quarter of 2023, and not in 2022 as previously planned, citing COVID-19 impact and restriction imposed at the fabrication yards.

Since then, this deadline has been pushed some more, with the first gas from Tyra II now expected in the winter season 2023/24.

"It’s exciting to be able to see the complete shape of Tyra II as all eight platforms, six bridges, two jackets, and one flare are now in their final position. I’m very proud of our installation team and our skilled partner Heerema Marine Contractors who once again executed textbook lifting operations. Nevertheless, there is still a lot of work offshore to complete in order to get Tyra II ready for first gas in the winter season 2023/24," said Lars Bo Christiansen, Deputy Project Director for TotalEnergies EP Denmark A/S, said after Heerema installed the final bridge in October 2022.

On the last day of June 2023, TotalEnergies said it had reconnected the 30-inch export pipeline between the Tyra field and Denmark, to enable the gas export once the field resumes its production.

In July 2023, TotalEnergies said its dedicated teams were working around the clock to ensure that the Tyra field would be back to production in the winter season of 2023/24.

During the Tyra redevelopment, Tyra and the surrounding fields were temporarily disconnected and the satellite platforms Svend, Roar, Harald, Valdemar, and Tyra South East were put into idle mode to enable the removal of the old Tyra and installation of the new Tyra.

In September 2023, the project reached another milestone with the final work on the subsea infrastructure, reconnecting Tyra with the surrounding fields.

Energy Security

Following the necessary Tyra shutdown for redevelopment works, in 2020, the total production of gas in Denmark dropped to 1.4 billion cubic meters, a steep decline compared to the gas production in 2019, where the total production was 3 billion normal cubic meters.

According to TotalEnergies, once the modernized Tyra II is back on stream, it will be the most modern natural gas field in the world and is expected to deliver 2.8 billion cubic meters of gas per year to Denmark and Europe through the export pipelines to Nybro and Den Helder.

The operator has said that the redevelopment will reduce CO2 by 30% and flaring can be reduced by 90%.

TotalEnergies has said that Tyra will play "a key role in making Denmark self-sufficient and net exporter of affordable and stable energy again – also to the benefit of our European neighbors."

This is especially important as Europe has been working to wean itself off the Russian gas, amid the conflict in Ukraine.

Denmark started extracting North Sea oil and gas in 1972 and is European Union's largest oil producer. In 2020 it set a final phase-out date of fossil extraction by 2050, including Tyra.

However, in April 2022, Reuters reported that the Danish government aimed „to significantly boost renewable energy supply and temporarily increase production of natural gas from its fields in the North Sea, in a move to rapidly become independent of Russian supplies.“

"We are convinced it's better to produce gas in the North Sea than buying it from Vladimir Putin," Reuters reported Prime Minister Mette Frederiksen as saying at the time.

New gas supplies will be appreciated even more as Rystad recently week said that global gas demand is projected to rise in the next decade, influencing a 12.5% surge in production between 2023 and 2030.

However, Rystad Energy forecasts that even in scenarios of 1.9 and 2.5 degrees Celsius warming, with rapid growth in renewable energy sources, the current set of existing gas fields will not meet global demand, and more new fields will be required.

As for Denmark, information on the Danish Energy Agency's website shows that after the reconstruction of the Tyra field, Denmark will remain a net exporter of natural gas until the mid-2030s while Denmark will remain a net importer of oil until the phase-out in 2050.