Knowing Subsurface Safety Valve- API14A

Close cooperation between Kerr-McGee and Schlumberger engineers helped
resolve challenges efficiently without impacting the critical timeline. For
example, long lead times often are required for material sourcing in ambitious
projects, so requirements for special materials or unusual equipment
specifications were identified early. This included obtaining material for
manufacturing valve components, because the relatively large diameter of
safety-valve components requires material in sizes that are not always
commonly available. Kerr-McGee engineers demanded redundant features
and safe operating characteristics. The TRC-DH safety-valve series was
specifically developed for this type of deepwater application. The valve design
incorporates a dual-piston operated control system that provides complete
operating redundancy. The gas-spring system provides substantially lower
control-line pressures at greater setting depths compared with conventional
valve systems. The surface controlline pressure for gas-spring valves in the
Nansen installation is less than 5000 psi [34.5 MPa] at surface, compared
with 10,000 psi [68.9 MPa] that would be required for conventional valve
operating systems.
Charlie Chong/ Fion Zhang