The close proximity of the Shell Goldeneye development to the shore (105km) and the fluid composition has enabled novel processing approaches to be considered. The 20” carbon steel full wellstream transfer pipeline will be the longest tieback in the UKCS, transferring gas and condensate under reservoir pressure direct to St Fergus via a small NUI platform. The selected development concept requires high confidence in protecting the pipeline against hydrates and corrosion over the life of the field.

Hydrates will be controlled by injection of mono-ethylene-glycol (MEG) and CAPCIS has undertaken extensive laboratory studies to assess corrosion control through pH adjustment of the MEG solution. The studies have included scale drop-out tests, assessments of the effects of MEG purity on corrosion rate and evaluation of the risk of localised corrosion of weldments.

The operational boundaries relating to aquifer production are uncertain and eventually the concentration of aquifer water may be such that corrosion management by pH control is no longer viable due to scale formation. A programme to assess conventional inhibitors for use when aquifer water production becomes unacceptable is now underway.