Page 30 - Practical Well Planning and Drilling Manual

Section 1 revised 11/00/bc 1/17/01 2:55 PM Page 6

[ ] Well Design
1.1.2

Any known restrictions on the mud systems to be used (e.g.,
for logging or reservoir damage)
Any other constraints on the well design or drilling program
from the well objectives
Any options that should be built into the well design, such as
later sidetracks to different reservoirs, etc.
A list of relevant offset wells
4. Specialist functions should specify:
Wireline logging program
Coring program
Geological surveying/mud logging requirements
Other evaluation requirements (e.g., paleontologist services, etc.)
Production test requirements
Final desired status of well; handover to production; suspend-
ed or plugged and abandoned (P&A)
5. Approval signature of the head of the sponsoring department—this
is to ensure accountability. It may also be necessary for the depart-
ment head to give you an account code to write the time against.

First, review the proposal and ensure that all necessary elements
are present as per the above checklist. Then try to identify any surface
or subsurface hazards arising out of the proposal and discuss these
with the sponsoring department to see if their proposal can be modi-
fied to eliminate or reduce the hazards. Review each element of the
proposal in detail. Is there any clarification required? Look in particu-
lar at the directional targets; these should be as large as possible and
ideally will indicate what defines the target boundaries (faults, prox-
imity to other wells, etc.). If “hard” target boundaries are given then
you know that if the well heads outside of that target, you may have to
sidetrack to get back into the target. This also gives you the largest pos-
sible target so you can later design your well to achieve the target at the
lowest cost. This becomes more important if multiple targets or inter-
mediate constraints on the wellpath are given. Often what happens is
that the target is a circle of stated radius around a defined location and
no indication is given as to where you can stray out of, which direction
is most critical, etc.
Explorationists rarely appreciate the effect on well cost that an
unnecessarily tight target can give. They know that if necessary you
can drill very accurately to a target and therefore that is what they spec-

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