Page 122 - Well Control for Completions and Interventions

114 Well Control for Completions and Interventions

Figure 3.21 A permanent packer.

The only notable disadvantage of using a permanent packer is its per-
manency, removal requires a milling operation. In a well where the pack-
ers are constructed from high grade stainless steel alloys, milling will be
more difficult; casing damage becomes a risk (Fig. 3.21).
Permanent packers can be run ahead of the completion. Packers that
have a long, heavy tail-pipe would be run on drill-pipe and set hydrauli-
cally or mechanically. More usually, the packer is run on e-line, enabling
very accurate depth determination. With the packer in place, the upper
completion is run. Seals on the tail pipe of the production tubing are
stabbed into the packer seal bore, isolating the annulus. Most permanent
packers only have short seal bores. If a high degree of seal movement is
expected, a seal bore extension can be run below the packer to protect
the seals during production.

3.10.2 Retrievable packers
Many retrievable packers are service packers of the type used during well
tests, interventions, cementing operations, and for temporary well aban-
donment. When run on a work string, they are normally set mechanically
by rotating the string and setting down-weight. Some are designed to be
set, released, and re-set a number of times in a single trip.
Retrievable packers used for completions are usually run with the
completion tubing and set hydraulically. In most cases they are retrieved