Page 142 - Well Control for Completions and Interventions

134 Well Control for Completions and Interventions

plastic encapsulation to help protect against crush damage. Bundling the
control lines also makes handling simpler when the completion is being
run. However, control lines complicate matters if there is a well control
incident as they prevent pipe rams and annulus rams from obtaining an
effective seal around the tubing. Additional measures need to be in place
when control lines are being run (or pulled) during a completion or
workover. Shut-in procedures for control line running are covered in
Chapter 7, Well Kill.

3.22 CONTROL LINE CLAMPS

Control lines and flat packs need to be adequately supported and
protected while the completion is being run, and throughout the life of
the well. Control line protection in early completions was rudimentary. It
was not uncommon to find control lines held in place with duck tape or
bits of rope. Steel “band-it” strapping was common, and is still used in
some very basic completions to the present day. The problem with these
“cheap and cheerful” techniques is that they often fail to do what they
are supposed to. Poorly supported control lines are susceptible to fatigue
failure, because of vibration when the well is on line. In addition, band-it
straps, duck tape, and rope are all a source of junk. A piece of duck tape
can easily block the port in a gas lift valve. Snapped band-it tape can find
its way into a PBR during a workover.
The first attempts to make dedicated control line clamps did not improve
matters a great deal. Clamps were made from hard rubber and held in place
with a steel pin. They were prone to damage, and were often missing when
tubing was pulled back. These early problems more or less disappeared with
the introduction of dedicated cast steel control line clamps.
Modern cast steel clamps are designed to sit across a tubing coupling.
Hinged fastenings are held in place by threaded or toggle connections. A well-
designed cross-coupling clamp both protects and supports all the control lines.
They are manufactured with a variety of internal profiles, cut to match the
size and number of control lines or flat packs being run in the well. Cross-
coupling clamps are normally run one clamp per coupling (Fig. 3.38).
“Mid-joint” clamps are also available. These can be run one per joint
in addition to the cross-coupling clamps. However, they have a tendency