Installation of 2-kilometer-long cooling bundle for North Sea field underway in Norwegian waters

August 29, 2024, by Melisa Čavčić

Norwegian oil and gas player Aker BP has confirmed the start of installation activities for a 2-kilometer-long cooling bundle at its field in the North Sea, as part of its development project which will ensure a lifetime extension for the Valhall field on the Norwegian Continental Shelf (NCS) past 2028.

Following the Storting’s stamp of approval for multiple projects, including the Yggdrasil and Valhall PWP-Fenris developments at the start of June 2023, the Norwegian Ministry of Petroleum and Energy greenlighted the developments at the end of the same month.

Eight months ago, Subsea7’s pipeline bundle fabrication site at Wick in Scotland, marked the start of two pipeline bundles of 6,8 kilometers and 7,6 kilometers in length, respectively, for Aker BP’s Yggdrasil project in the North Sea, with the facility also expected to produce a 2-kilometer cooling bundle for the Fenris project.

The Yggdrasil project, encompassing the Hugin, Fulla, and Munin assets nestled between Alvheim and Oseberg, is in the execution phase with construction activities underway, the two project managers, Per Moi and Rasmus Haneferd from Subsea7, describe it as being the largest project any of them have led, both in scope and value.

Aker BP is the operator with Equinor and PGNiG Upstream Norway as its partners. Global Energy Group recently won a contract to build 134 subsea spools for Yggdrasil. The first steel structures for the topside at the operator’s Munin unmanned production platform, which started their journey from Aibel’s Thailand shipyard, are expected to reach its Norwegian yard in autumn.

Believed to be among the world’s longest fabricated items ever moved, the pipeline bundles were to be submerged and towed to the installation site using Subsea7’s controlled depth tow method. The bundles neatly incorporate all structures, valve work, pipelines, and control systems necessary to operate a field in one single product, delivering considerable value and potential cost savings for projects.

Set up in 1978, the fabrication site in the North of Scotland near the town of Wick produces pipeline bundles to satisfy the requirements of oil and gas developments in the North Sea but it has also been extended over the years to meet the demands of longer subsea tie-backs and is currently 7.8 km long. The Aker BP bundles were set to be the 89th, 90th, and 91st bundles launched from Wester since the start of the site.

Aker BP revealed in June 2024 that six offshore campaigns would be carried out to install almost 100 km of pipelines over the summer at its Fenris 14” production and 4.5” MEG pipelines development project in the Norwegian sector of the North Sea.

After loading out the 2-kilometer-long cooling bundle for the Fenris field and towing the long pipeline slowly to sea, the partners in Aker BP’s Subsea Alliance, consisting of Aker Solutions and Subsea7, managed to transport it from Scotland to the field’s location in the Valhall area. As a result, the Subsea Alliance has begun installing the bundle as the first of five planned to be put in place.

Aker BP marked the start of the fabrication phase for Valhall PWP, with the cutting of the first steel plates at Aker Solutions’ yard in September 2023. Several months later, the Fenris jacket and pre-drill module (PDM) embarked on its journey to the Valhall field from the yard in Verdal with three different tugboats maneuvering the giant barge out of the harbor. The trip to the field for installation was expected to take five days.

Located in the southern part of the North Sea, the Valhall PWP-Fenris development includes a new centrally located production and wellhead platform linked to the Valhall field center by a bridge and an unstaffed installation at Fenris that will be tied back to Valhall through pipelines on the seabed. While the 16,000-tonne Valhall PWP production platform for the Valhall field will be assembled at Stord, the 9,500-tonne steel jacket will be delivered from Verdal.

The field development also encompasses the Fenris unmanned platform being delivered from Verdal. Aker Solutions’ scope covers considerable subsea and modification deliveries to the Valhall PWP-Fenris project. Pandion Energy is Aker BP’s partner in Valhall and PGNiG Upstream Norway is the firm’s partner in Fenris, which is 50 kilometers away.

The Valhall PWP-Fenris development will use the existing power from the shore system and new reserves from the development project are estimated at 230 million barrels of oil equivalent. The total investment for the North Sea project is approximately NOK 50 billion ($4.6 billion), with around 65% of the work expected to be carried out by Norwegian suppliers.