Watch complex subsea operation of installing Dvalin Xmas trees

Wintershall Dea last December installed three Xmas trees on its Dvalin gas development, which has now moved from the drilling phase to the completion phase – into the direction of the first gas.

Dvalin Xmas tree; Source: Wintershall Dea
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The Wintershall Dea-operated Dvalin gas field is located in the Norwegian Sea.

It is being developed as a subsea tieback with four subsea wells, tied back to the Equinor-operated Heidrun host platform, using a subsea template on the seabed.

Using the Transocean Arctic rig, Wintershall Dea started drilling four production wells on the Dvalin gas field back in August 2019. These operations were expected to last about a year.

First gas from the field is expected to be produced in the fourth quarter of 2020.

In December 2019, under harsh weather conditions in the Norwegian Sea, the 52 tonnes Xmas trees were lowered almost 400 metres down to the seabed at the Dvalin field, 260 kilometres north of Kristiansund.

The Xmas trees are a set of valves and other equipment that secures the well and are key components for drilling the production wells at Dvalin.

Tore Øian, Dvalin drilling manager, said: “It was a complex subsea operation with big swells, waves and tide. Under these conditions, the rig was constantly moving, and it was very challenging to control the 52 tonnes Xmas trees and let them safely down to the wellhead on the seabed. It required a high level of coordination between all the parties involved”.

Wintershall Dea has already received consent from Norway’s Petroleum Safety Authority to use the facilities on the Dvalin field.