Page 121 - Well Control for Completions and Interventions

Completion Equipment 113

3.9.2 Blast joint
Blast joints are used in multiple zone wells where the completion runs
across open perforations. Blast joints are used to counteract the erosion
effects caused by jetting from perforation tunnels.

3.10 PRODUCTION PACKERS

Production packers create a seal between the outside of the produc-
tion tubing and the casing or liner. They protect the casing from the
potentially corrosive effects of produced fluids, and form a well control
barrier. Packers are used in multiple layer reservoirs to provide isolation
between each different producing zone. They are also used as service
tools during well tests, stimulation operations, and during remedial
cementing.
Not all wells require packers, they are rarely used in rod pump wells,
and many ESP completions are run without packers.
Although packers are used for a wide variety of applications, most share
some common characteristics. They all have a mandrel to enable fluid
flow through the packer, slips to anchor the packer to the casing wall, and
an elastomer element that extrudes to seal against the casing wall. There
are three classifications of packer: permanent, retrievable, and permanent/
retrievable. They are set using mechanical manipulation, hydraulic or
hydrostatic pressure, or wireline conveyed explosive setting kits.

3.10.1 Permanent packers
Permanent packers are usually simple, cheap, and robust. In general they
are able to withstand much higher tension, compression, and differential
pressure than retrievable packers. They generally have a larger through
bore than the retrievable equivalent, and are ideal for the following
applications:
• high pressure completions,
• high volume completions,
• high pressure/high volume frac jobs with anchored or floating tubing,
and
• isolation of a lower zone by using a permanent packer as a bridge
plug.