Page 46 - Drilling Technology in Nontechnical Language

Chapter 3 – DRILLING A LAND EXPLORATION WELL 37

g. Whether core samples of rock should be obtained and at what
depths. (A core is a sample of rock obtained by coring, which
uses a bit with a hole in the middle and recovers a column
of rock.)
h. What should happen to the well after operations are complete
(abandoned or temporarily secured for possible later use).
i. The completion design for the well (see below for
an explanation).
First, the drilling department needs to review the well proposal to
establish that the following criteria are met:
1. The proposal is logical, and the objectives are achievable.
2. The essential well design data is complete, and there are no
ambiguities or omissions.
3. The directional targets that the well needs to hit are as large as
possible. The smaller the target, the more the well is likely to cost.
4. The proposal does not give rise to any inherent hazards that
might create a danger to personnel or to the rig or the well.
Once the well proposal is agreed upon by all concerned parties, the
drilling department will look for any available information to help the
drilling engineers design the well.

Well Design and Drilling Program

A well design defines the final status of the well; that is, what is left

behind when the rig leaves the location.
A drilling program is a document that the drilling engineers use to
advise the rig how the well design might best be achieved. If the well design
is the destination, then the drilling program is the road map to reach the
destination. However, the drilling program should not be considered to be

a definitive document that must be followed without modification. During
the drilling of a well, there will be unplanned events or circumstances
requiring changes to be made in order achieve the required well design in
a cost-effective manner.

These two documents will be looked at separately.

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