WATCH: World’s largest offshore construction vessel takes former platform’s jacket out of North Sea as recycling time comes

Switzerland-headquartered offshore pipeline installation, heavy lift, and subsea construction contractor Allseas has performed another removal task in the North Sea with its giant offshore construction vessel for Aker BP, a Norwegian oil and gas player.

The Norwegian Ocean Industry Authority (Havtil) gave Aker BP consent in March 2024 for the disposal of a steel jacket belonging to the former riser platform 2/4-G on the Ekofisk field, which was owned by the Valhall field and operated by ConocoPhillips through an agreement with the former BPAmoco. Aker BP took over the ownership in 2016.

Allseas signed a frame agreement with Aker BP in 2017 to provide transport, installation, and removal services on the Norwegian Continental Shelf (NCS), which also entailed the Valhall campaign. Pioneering Spirit removed the accommodation platform (QP) topsides in 2019 and the jacket in 2021.

The platform was the first of the three original structures – QP, DP, and PCP – to be removed as part of the modernization of the Valhall field center by Aker BP and other campaigns were planned for the removal of the PCP jacket, the unmanned Hod A platform 13 km to the south of Valhall, and the 2/4-G jacket on the Ekofisk field situated 24 km north.

According to Aker BP, the Ekofisk 2/4 G jacket was removed from the seabed by Allseas’ Pioneering Spirit vessel earlier in the summer and transported to Aker Solutions’ Stord yard, which will demolish and recycle the jacket, with nearly 100% of the materials being recycled.

The 2/4 G jacket was part of the Ekofisk field’s 2/4 G riser platform for transporting oil and gas from the Valhall field, which was installed in 1981 and became operational in 1982. The platform was bridge-connected to 2/4 T, but after operations ceased in 1998, the bridge was removed in 2014, and the topsides followed suit in 2016.

The Ekofisk 2/4 G jacket, which is ready for recycling after being removed by Allseas’ heavy lift vessel, was cut in two due to height constraints and both parts were lifted onto the aft deck by the 5,000-ton crane. Once both parts were secured, the Pioneering Spirit vessel sailed to Stord for the load-in. Aker BP confirmed that the operation went according to plan and was executed safely and efficiently.

Ekofisk 2/4 G jacket ready for recycling

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This announcement comes shortly after the Norwegian player made progress at its oil field life extension project by installing a new jacket in the North Sea with a semi-submersible crane vessel (SSCV) owned and operated by Heerema Marine Contractors.

The jacket is part of a development project that aims to extend the life of the Valhall field on the Norwegian Continental Shelf (NCS) for another 40 years, with the total new reserves estimated at 230 million barrels of oil equivalent.