GOUDA, the Netherlands – Mokveld is to provide subsea anti-surge control valves for Statoil’s Åsgard subsea gas compression project in the Norwegian Sea.
Subsea gas compression is a new technology designed to lift recovery from and lengthen the lifespan of offshore gas fields.
Statoil contracted Aker Solutions to supply a subsea compression system for the Åsgard field. One issue that had to be addressed was the development of large fast-acting subsea control valves.
Mokveld, which has developed an axial flow design in its valves for severe service in topsides application, was approached to investigate development of this concept as the basis for a subsea control valve.
In cooperation with Oceaneering, FMC, and Aker Solutions, Mokveld developed and qualified an 8-in. API 5,000 subsea axial control valve. The qualification program included an API 6A PR2 test, endurance testing with 500,000 cycles, and hyperbaric testing simulating seabed conditions. Additionally, a valve was supplied to the Ormen Lange subsea compression pilot project extended life test at Shell Nyhamna in western Norway.
For Åsgard, Mokveld’s is supplying three 8-in. API 5,000 subsea control valves with electrical spring to open Oceaneering actuators. They will be used in a quick-opening anti-surge control application, and operating at a water depth of 250 m (820 ft).
The qualified axial valve design is said to be suitable for subsea anti-surge and separator control applications, and for subsea HIPPS applications in accordance with API RP17O.