Ship report – Safety and economy are priorities

The recently completed floating production, storage and offloading (FPSO) vessel Varg is designed for use in the harsh environment of the North Sea.

Delivered in September by Keppel FELS Singapore Ltd, Varg is owned by independent Norwegian oil company Saga Petroleum and was designed and constructed to work in the Varg Field, which is owned by Saga Petroleum (35 per cent) and Norway`s state-owned oil company Statoil (65 per cent).

The Varg Field is a marginal field located in the harsh and demanding environment of Block 15/12 in the Norwegian sector of the North Sea, approximately 32km south of Sleipner East and close British waters.

The strategy adopted to exploit the field consists of an unmanned wellhead platform (WHP) with production, gas injection, and water-injection wells connected to the FPSO. Operation of the WHP is carried out remotely from the FPSO, and the processed crude is stored in the vessel prior to being offloaded to shuttle tankers for transportation to refineries.

Given that the field is a marginal one, the overall cost of the FPSO was extremely important to the owner. This being the case, a decision was taken to base the design of the FPSO for the Varg field on the Tentech 700 SP, a type of single-hulled, turret-moored FPSO vessel with a total of 16 risers, which was originally designed by Maritime Tentech, part of the Aker Maritime group.

FPSOs designed by Maritime Tentech have been selected for a number of major projects in the North Sea. A Tentech 850S, also built by Keppel Fels, was selected for the Norne field, and a Tentech 900S was selected for the Asgard project in 1996. Another version of the Tentech 700 – a Tentech 700 T – was selected for production and storage in Texaco`s Captain field in the UK sector.