A tie-back reception facility for third-party gas on Cygnus.

Development project


Gas and condensate


United Kingdom



Project details

Pegasus is a third-party subsea gas development operated by Spirit Energy and Hague and London Oil. The Pegasus West gas discovery lies in UKCS Block 43/13b in the UK Southern North Sea to the West of the Cavendish field. Pegasus West is a gas and condensate discovery with an initial production plateau of 70 kscfpd, a condensate gas ratio of 0.9–7.2 bbl/kscf and total recoverable reserves of around 83 bcf.

The selected concept for further development was a 57 km subsea tie-back and the installation of a new topsides process module on the Cygnus Alpha PU platform processing the Pegasus fluids for export into the Cygnus export pipeline. Its Front End Engineering Design (FEED) phase is currently nearing completion. The engineering work completed has identified potential constraints on future Greater Cygnus Area development opportunities.

Neptune is assessing the economics of provisioning for this scheme. It will involve development of greenfield and brownfield modifications including a new Pegasus Processing Module to receive and process gas from Pegasus.

The commercial logic of developing this capability may be dictated by its opportunity cost. Current indications are that Cygnus will only be able to accommodate a single tie-back. Developing Pegasus may therefore limit future development possibilities.

Project status

As at 15/02/19

Studies are underway to confirm the extent of any tie-back limitations. Neptune has requested a temporary halt in development so that it can engage with the regulator and with Spirit Energy.


Spirit Energy (55%), Hague and London Oil Plc (45%).


Spirit Energy