Surface controlled subsurface safety valve assembly with primary and secondary valves

摘要

A surface controlled subsurface safety valve assembly includes primary and secondary valves, such as an upper and lower flapper valve. Only one of the valves is in service at a time. In the event that the primary valve is compromised, and therefore leaks, the SCSSV is shifted to position the primary valve out of service and the secondary valve in service. The SCSSV may have more than two flappers, thereby providing multiple secondary valves, with only one valve in operation at any one time.