The Aasta Hansteen Platform (Credit: Woldcam/Equinor/Aibel AS)
The Irpa Gas Discovery is located in deep sea water in the Norwegian Sea. (Credit: Equinor ASA)
Irpa pipe-in-pipe solution. (Credit: Kjell Morten Aas / Equinor ASA)

Irpa, formerly known as Asterix (6705-10/1), is a deep-water gas discovery being developed in the Vøring Basin in the Norwegian Sea.

The discovery was proven in 2009.

Equinor Energy is the operator of the project with 51% interest, while Petoro (20%), Wintershall DEA (19%) and Shell (10%) are the other partners.

The Plan for Development and Operation (PDO) for Irpa was submitted to the Norwegian Minister for Petroleum and Energy Terje Aasland in November 2022. The development of the project will entail an investment of NOK14.8bn ($1.5bn).

The gas field is expected to host approximately 124 million barrels of oil equivalent (b.o.e) which includes 19.3 billion standard cubic metres (sm3) of gas reserves and 0.4 million sm3 condensate reserves.

The gas volumes are equivalent to the consumption of more than 2.3 million British households for seven years.

Irpa is expected to commence production in the fourth quarter (Q4) of 2026.

Location and site details

Irpa is located in the Vøring Basin in the Norwegian Sea, about 340km west of Bodø and 80km west of the Aasta Hansteen Platform. The water depth at the location is around 1,350m.

The gas reservoir is located in turbidite sandstone of the Late Cretaceous age in the Springar Formation at a depth of 3,200m.

The project will be tied back to Aasta Hansteen, one of the deepest field development on the Norwegian continental shelf.

Project details

The Irpa development will include three wells and an 80km tie-back pipeline to the Aasta Hansteen Platform. The subsea template will have four well slots that would be tied back to the Aasta Hansteen facility.

The gas will be transported from Irpa to the Aasta Hansteen Platform’s existing infrastructure and then to the Nyhamna Processing Plant via the 482km long Polarled pipeline.

Subsequently, the gas will be exported to the customers in the UK and continental Europe through the Langeled Pipeline System.

The Irpa Gas Discovery will extend the life of Aasta Hansteen Platform by seven years from 2032 to 2039.

Irpa and Aasta Hansteen will produce jointly through to 2031, while Irpa continue to produce until 2039.

The pipeline to Aasta Hansteen will be made of a new insulated pipe solution considering the extreme cold on the seabed.

The move will involve the use of a swaged pipe-in-pipe design with a combination of insulation and vacuum between the inner and outer pipes, along with monoethyleneglycol (MEG) injection to minimise hydrate formations in the multi-phase well stream.


The Irpa gas development and the resulting life extension of the Aasta Hansteen Platform will help in sustaining several jobs both onshore and offshore.The development of the project will extend activity at supply base in Sandnessjøen, the helicopter base in Brønnøysund, and the operations organisation in Harstad. It will also create significant value through jobs and local spin-offs.

It is estimated that the project will involve 294,000 working hours during offshore development and modifications stages.

In 2020 and 2021, operations at the Aasta Hansteen Platform provided jobs equivalent to more than 300 full-time persons-year directly and indirectly.

The development of Irpa is also expected to stabilise gas supplies to Europe.

Contractor involved

On 22 November 2022, Aibel secured a contract from Equinor to carry out extensive modifications and preparation of the Aasta Hansteen Platform related to the Irpa gas development tie-in.

The award was categorised as a large contract with value ranging between NOK1.5bn and NOK2.5bn. At peak, the works will employ over 200 people.

The management and engineering works will be carried out from at Aibel’s office in Stavanger, while the company’s Singapore and Oslo offices will provide necessary support.

Aibel plans to leverage synergies with existing maintenance and modification contract for Aasta Hansteen.

The prefabrication and module assembly will be completed at Aibel’s yards in Haugesund and Thailand.

Aibel was also awarded Front End Engineering and Design (FEED) contract for the modifications in 2021.