Page 49 - Practical Well Planning and Drilling Manual

Section 1 revised 11/00/bc 1/17/01 2:55 PM Page 25

Precompletion and Completion Design [ ]
1.3.2

ried out during stimulations.
Injection pressures for gaslift must be considered for casing burst;
also remember that if the production casing leaks, this pressure
will be exerted against the previous casing.

Workovers and recompletions.

Provision may need to be made for a different completion in the
future; for instance as the well depletes it may be desired to run gas
lift valves, submersible pumps, or other tools. The casing design
will have to account for these future possibilities.
Where other zones may be produced later on, the casing design
will have to ensure that the required zones are accessible (e.g., not
behind multiple casings), and that the cement sheath at that depth
is high-compressive strength and provides good zonal isolation.

Abandonment. Eventually the well will be abandoned.
Government regulations may require certain actions to be taken. For
example, in Egypt it is required that all annuli have cement between
the casing and open hole, even though no permeable zones may be
present. This is not currently a requirement in the North Sea. It is
important to know these details at the well design stage to avoid
unnecessary work in the future.
Restoration of the site after abandonment should also be consid-
ered at the well design stage to minimize the expense later on.

1.3.2. Monobore Completions

Monobore completions (where fullbore access to the production
zone is possible through the completion tubing) allow hole sizes to be
decreased with no loss of production compared to traditional comple-
tions. (See Fig. 1-3)

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