| 摘要 |
An existing safety valve is removed from a production tubing safety valve nipple 12, a velocity string 24 is run into the production tubing 10 to engage the safety valve nipple 12 and then a velocity string safety valve 26 is run into the upper end of the velocity string 24 and coupled with a port 20 with control lines 22 at the safety valve nipple 12. A no-go engaging key 32 on the velocity string 24 engages a safety valve nipple no-go 14, forcing an extendable profile-engaging key 34 within a profiled member 36 on the string 24 outwards - as the no-go key 32 retracts - to engage with locking profile 16 on the production tubing 10. The string 24 is secured and supported in the production tubing 10 without the need for packers. The keys 32,34 may be dogs, part-circular segments or split rings, for example, and the valve 26 may include a sprung flapper. |
