Rambøll Oil & Gas has submitted a study which sheds light on the advantages and disadvantages of unmanned wellhead platforms.

The study was commissioned by the Norwegian Petroleum Directorate (NPD), which has taken a positive view of unmanned wellhead platforms, considering concepts of this type to be an important contribution to good resource utilization and an alternative to subsea developments.

The conclusion is that unmanned platforms may provide efficient development solutions in terms of costs and production for shallow water developments on the Norwegian shelf.

Unmanned wellhead platform concept

An unmanned wellhead platform is a facility resting on the seabed where the wells are placed on the platform deck. The concept is an alternative to subsea wells with wellheads situated on the seabed.

There are various types of unmanned wellhead platforms – from simple facilities to more advanced solutions which include e.g. process equipment. Access may be via gangway from vessels, while others have helicopter decks.

Statoil’s Oseberg Vestflanken 2

In December 2015, Statoil and its partners submitted a Plan for Development and Operation (PDO) for Oseberg Vestflanken 2 in the North Sea, where the development concept entails an unmanned wellhead platform, a jack-up rig and a support vessel.

The Oseberg Vestflanken will consist of an unmanned wellhead platform with 10 well slots. The wells will be remote-controlled from the Oseberg field centre.

Statoil has reduced total investment costs by around NOK 1 billion following the concept selection.

Rambøll study

The main topics that were addressed in Rambøll’s study include:

· Basic types and locations for unmanned platforms;

· Experience from operation and maintenance of unmanned platforms;

· Regulations and framework conditions, Norwegian shelf and comparable continental shelves.

Development of these types of concepts comprises both technical solutions and regulations. Amendments to the regulations are handled by the Petroleum Safety Authority Norway.