Unmanned minimum-facility platforms are a cost-effective alternative to subsea production systems. Statoil contracted Ramboll to carry out a study on an unmanned wellhead platform (UWP) for their Oseberg field.
Statoil has adopted the concept of the unmanned wellhead platform for the development of the Oseberg field in the Norwegian North Sea. Ramboll’s 2015 study investigated a viable alternative to the subsea tie-back; an alternative which would provide a cost-efficient development solution at Oseberg.
Limiting visits to reduce costs
The overall design philosophy was to minimize the equipment on the platform, thus minimizing the requirement for visiting the platform for operation and maintenance. Visits to the platform were proposed limited to twice a year except for unplanned well maintenance. Further, focus was on efficient and safe evacuation if for some reason a leakage and/or fire should occur during a visit.
Saving several millions
Statoil chose the jacket-based unmanned wellhead platform due to cost reduction of several hundred million Norwegian kroner. Moreover, the total cost for unmanned wellhead platforms are found to be very competitive to a subsea concept, all elements of construction, equipment, wells and maintenance considered. Statoil and its licence partners continue to carry out pre-studies of the unmanned wellhead platform.