Åsgard

The field consists of the Midgard, Smørbukk and Smørbukk South deposits. The Mikkel gas field and the Morvin and Trestakk oil fields are also tied into the infrastructure on Åsgard. The field development concept includes the Åsgard A production vessel, the Åsgard B semi-submersible facility and the Åsgard C storage vessel. Åsgard has produced oil since May 1999 and gas since October 2000.

The Åsgard A production vessel was in place on 8 February 1999, and started producing oil on 19 May.

Åsgard B is a semi-submersible floating platform with processing facilities for gas treatment and stabilisation of oil and condensates which came on stream on 1 October 2000. The platform was developed by Kværner and the hull was built by Daewoo Heavy Industries in Korea. The topside modules came from Poland, Russia, the Netherlands, Sweden and Egersund, and were mated with the hull in Stavanger. In 2000, the platform was the largest semi-submersible platform ever built for production, with a topside weighing 33,700 tonnes.

Åsgard C is a storage vessel for condensate stationed at the field.

Today, a look at the seabed reveals one of the most advanced and complex subsea facilities ever constructed, with more than 70 wells distributed across 23 subsea templates. The production systems are spread across an area of 20 x 60 kilometres, larger than the entire city of Rome.

The Åsgard facilities currently receive oil and gas from seven different fields: Midgard, Smørbukk, Smørbukk South, Mikkel, Morvin, Smørbukk Northeast and Trestakk. Morvin (four wells and two subsea templates) and Mikkel (three wells and two subsea templates) also produce to Åsgard B.

Saga proved Midgard in 1981. Equinor discovered Smørbukk in 1984 and Smørbukk South in 1985. In 1995, the stakes in the field were coordinated in a new ownership structure with then Statoil, now Equinor, as operator.

Water depth in the area is 240-310 metres.

Oil, condensate and gas are all produced at Åsgard. Crude oil and condensate are mixed to form an oil grade called Åsgard Blend. The liquid is pumped from storage tanks over to shuttle tankers that sail between the field and various refineries.

With the development of Åsgard, Haltenbanken became linked to the gas transport systems in the North Sea, which meant that the long-standing planned pipeline connection between the Norwegian Sea and the North Sea could finally become a reality. The gas from the Åsgard field is routed by pipeline to Kårstø in Northern Rogaland county, where heavier components such as ethane, propane, butane and naphtha are separated out. From there, the dry gas is transported onward via the Europipe II pipeline to customers on Continent.

Technological development has been a red thread ever since the Plan for Development and Operation (PDO) of the Åsgard field was submitted to the authorities in 1996.

The world’s first subsea gas compression system came on stream on 16 September 2015. This is one of the most demanding technology projects ever implemented with the objective of improved recovery.

This subsea technology yields a significant reduction in energy consumption and CO₂ emissions in a life-cycle account for Åsgard. Through further optimisation, the technology also represents a potential for additional CO₂ reductions in future subsea solutions.

The two gas compressors installed on the seabed are situated near the wellheads at Midgard. Moving gas compression from platform to wellhead substantially improves recovery and field lifetimes.

The recovery rate for the Mikkel and Midgard fields that are tied into the facility will increase from less than 60% to close to 90%. All in all, this means that an extra 306 million barrels will be extracted from the two reservoirs, mainly gas.

The project has a complete spare parts train available in Kristiansund, which makes it possible to replace parts if we encounter problems with the technology. The system is modular, almost like Lego blocks.

The compressor shaft – which weighs in at seven tonnes all on its own – is held in place in a magnetic force field in the bearing. This means less need for maintenance on the compressor, or practically no maintenance at all.

The Mikkel field is situated 35 kilometres south of the Åsgard deposit Midgard. Mikkel’s development concept utilises a subsea facility where the wellstream is tied into the subsea facility at Midgard, which is part of the Equinor-operated Åsgard field. The field has produced gas and condensate (light oil) since 1 August 2003.

The subsea plant on Mikkel consists of two subsea templates with a total of three production wells. Mikkel is the first in a number of fields in this part of the Norwegian Sea where development has been made possible thanks to the infrastructure established through the Åsgard development.

The condensate is transported by pipeline to the storage vessel on Åsgard C for export, while the gas is routed to Kårstø in Northern Rogaland through the Åsgard Transport Pipeline.