Armada; Source: Shell

Authorities assessing Shell’s Gaupe tieback decommissioning plan

UK authorities are assessing the plan for the decommissioning of the infrastructure associated with Shell’s Gaupe field subsea tieback.

Armada; Source: Shell
Gaupe and Armada map; Source: Shell
Gaupe and Armada map; Source: Shell

The field comprises two production wells in the Norwegian sector, Gaupe North and Gaupe South.

Fluid from the two drill centres are commingled at the Gaupe SSIV manifold, located close to the Armada Complex located in the Central North Sea, 250 kilometres East of Aberdeen on the UKCS.

The wells are tied back to the Armada Complex via two pipe-in-pipe systems and a flexible riser which was installed within a platform conductor caisson. Controls for the field are provided by the Armada facilities via two electro-hydraulic control and chemical supply umbilicals, one to each drill centre.

Armada’s gas and condensate are sent towards the North Everest platform, with gas entering CATS at the CATS riser platform and condensate enters the Everest Lomond System pipeline before joining the FPS pipeline at Forties Charlie.

Separation of Armada from decom plan

The Armada facilities, CATS riser and facilities beyond are not part of the decommissioning programme.

The Gaupe wells were tied back through the Gaupe field pipelines to the Armada complex. They came on stream in the first quarter of 2012.

Gaupe and Armada Hub layout; Source: Shell
Gaupe and Armada Hub layout; Source: Shell

It is worth noting that the Gaupe field assets were originally included within draft decommissioning proposals for the Armada Hub. Approval-in-principle from the OGA for the cessation of production of the Armada Hub and associated tiebacks was granted in August 2016.

In November 2017, the Armada Complex was divested to Chrysaor with the intent of extending field life and CoP was deferred.

The Gaupe wells and associated subsea infrastructure were not part of the divestment and remained within the Shell portfolio.

Production was temporarily suspended in August 2018, and after clarifications regarding future use, the owners declared CoP in December 2019.

Decommissioning plan

Shell’s plan includes the full removal of the SSIV, two risers, two pipelines, and the partial removal of two umbilicals, as well as any associated apparatus up to the UK-Norway median line.

As the field is located on the Norwegian Continental Shelf a separate decommissioning plan has been submitted to the Norwegian authorities for approval.

Due to the Gaupe subsea infrastructure decommissioning scope being limited, Shell will seek synergies with other projects to be able to perform the operations in a cost-efficient manner.