Page 58 - Practical Well Planning and Drilling Manual

Section 1 revised 11/00/bc 1/17/01 2:55 PM Page 34

[ ] Well Design
1.3.6

1.3.6. Points to Check on the Completion Design

While the drilling department does not usually design the pre-
completion and completion (because this is a specialist task as can be
seen from the factors mentioned in the previous section), it is impor-
tant to check the design and make sure that there are no practical prob-
lems with it. Some specific points to check include:

Clearances inside the planned production casing or liner. Various
accessories will be run on the completion tubing such as packers,
side pocket mandrels, nipples, etc., that have to fit inside the cas-
ing.
Dual or triple completion strings can be run. If completion acces-
sories are run at the same depth on different strings, that can cause
real problems running. For instance, a side pocket mandrel is not
round in cross section, but if run on a dual 3 1 /2 in completion, it
has to be aligned sideways to the other tubing string or else it can
crush the other tubing inside 9 5 /8 in 47 ppf casing. Control and
injection lines may be run (i.e., to a surface controlled subsurface
safety valve). Clearances in these complex completions must be
examined and may require redesign and/or special running proce-
dures.
In a deviated well, wireline tools get hard to run above 50˚ inclina-
tion. If profiles are run in the string that require slickline interven-
tion (to operate sliding side doors or set/pull injection valves), then
they need to match your directional plan to ensure that they can be
reached on slickline. Otherwise, it may be possible to design these
accessories to be worked by coiled tubing if repositioning is not
possible.
Completion components should be checked under the different
operating conditions for burst, collapse, and tension. The different
operating conditions may include several of the following:
Running
Spacing out and landing
Pressure testing
Stimulation, including fracs and acid jobs
Producing throughout the life of the well (initial and depleted
reservoir pressures)

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