Vega Gas and Condensate Field

Vega is a gas and condensate field that lies in Block 35/8 and 35/11 in the Norwegian North Sea. It is located in the Q35 area of the North Sea around 30km west of the Gjøa field.

The field is situated approximately 80km west of Florø in Sogn og Fjordane, western Norway, at a water depth of about 380m.

Vega was first discovered in 1981 and was proven through the Camilla, Belinda and Fram B (1987) finds made in 1980, 1982 and 1987, respectively.

It is developed with three underwater templates- Vega North, Vega Central and Vega South. The templates are tied back to a processing facility on the Neptune Energy-operated Gjøa platform.

The Vega North and Central are gas condensate fields, while the Vega South is a gas condensate field overlain by an oil zone.

In March 2015, Wintershall Norge acquired the Vega field from Statoil (now called Equinor) and operates it with a 56.7% interest. The other partners are Petoro (31.2%), Spirit Energy (5.5%), Neptune Energy (3.3%), and Idemitsu Petroleum (3.3%).

Vega began production in 2010. According to the Norwegian Petroleum Directorate, around NOK11.2bn ($1.09bn) has been invested in the project until 31 December 2020.

Site details and reserves

Vega North, Central and South lie in production licences 248, 248B and 090C, respectively.

The field reservoirs are located in the Middle Jurassic shallow marine sandstone in the Brent Group at a depth of 3,500m. Vega South additionally has an oil zone overlying the condensate deposit.

Originally, the deposit was estimated to host 49.8 million standard cubic metres (scm) of reserves.

It is now expected to contain 2.72 million scm of oil, 10.6 billion scm of gas and 2.65 million tonnes of natural gas liquids.

Vega field development

The plan for development and operation (PDO) for Vega North and Vega Central was approved in 2007.

In 2011, the field was combined with Vega South.

Each of the three fields is equipped with a four-slot subsea template. The well stream is transported to the processing facility on the Neptune Energy-operated Gjøa platform via a subsea tieback.

Subsequently, the gas recovered from the field is exported to St. Fergus in Scotland, whereas the oil/condensate is sent to Mongstad in Norway.

A total of six production wells were drilled at Vega. All three structures leverage the drainage strategy of production by depletion, with no pressure support.

Thereafter, two production wells at Vega Central and one in Vega South were drilled under an infill drilling programme.

The new well at Vega Sør has begun production.

One of the wells in Vega central will be permanently plugged and abandoned, while the remaining one is slated to commence production in 2022.

The production at Vega field is now limited by gas production capacity rights at Gjøa.

Transport

From the Gjøa platform, the oil and condensate are transported to the Troll Oil Pipeline II for export to the Mongstad terminal.

The gas produced by the field is transported from Gjøa to the Far North Liquids and Associated Gas System (FLAGS) on the British continental shelf and then to St Fergus in Scotland.

Contractors involved

In 2007, FMC Technologies secured the contract to deliver underwater installations for the Vega field. The scope of deliveries included six crosstrees and three-manifold modules with associated protection frameworks and systems.

During the construction of the development, the Fjord Base in Florø was utilised as the storage location for materials for the operations on the seabed.

Heerema was responsible for heavy lifts for the installation of subsea structures, while drilling, completion and clean-up of wells were carried out using the Bideford Dolphin facility from Dolphin Drilling.

Subsea 7 secured the contract for the delivery and installation of flowlines and umbilicals to the Gjøa platform.

Wintershall used Island Offshore’s Island Frontier and Island Wellserver vessels for intervention work on the Vega field.