Page 126 - Well Control for Completions and Interventions

118 Well Control for Completions and Interventions

a static connection, the fourth uses a dynamic seal, allowing tubing
movement.

3.12.1 Premium threads
The simplest, and the most reliable, method is to screw the tubing
directly into the top of the packer with a premium thread connection.
When tubing is connected to a packer using a thread, pressure integrity
comes from the seal face on the thread profile. All of the alternative
methods of connection rely on elastomeric seals, and are not as reliable in
terms of pressure integrity.

3.12.2 Ratch latch or anchor latch

Tubing can be connected to the packer using a stab-in ratchet mechanism
commonly referred to as a “Ratch Latch”. This has a coarse thread (usu-
ally left hand) that can be snapped into a profile in the top of the packer
by the application of down-weight. Elastomer seals, positioned below the
latch mechanism, seal in a honed bore in the top of the packer. Most
latches are removed by clockwise rotation (Fig. 3.25).

3.12.3 Locator seal assembly
A locator seal assembly is a series of elastomer seals arranged along the
length of a mandrel that are designed to locate in the packer seal bore.
They are free to move (dynamic) when the well is in service. Having a

Figure 3.25 Ratch latch assembly.