Page 207 - Practical Well Planning and Drilling Manual

Section 2 revised 11/00/bc 1/17/01 12:04 PM Page 183

2.4.2
Drill Bit Selection, Parameters, and Hydraulics [ ]

The elements of this approach are explained individually in this
section. It works well in practice, but the usefulness is relative to the
amount of effort and expertise put into it.
There are two (paper) methods that summarize and present a large
amount of data in a way that is useful for well planning and drilling
operations. These are described under Preliminary Work for Well
Design. In addition, a computerized bit database that is good for ana-
lyzing the bit runs and for fast access to a large amount of data in the
office or field is used.
The central data summary tool is the hole section summary. This
document can display a lot of information in a way that allows fast and
meaningful comparison of data from multiple wells. It can be con-
structed on quite a basic level using only information from offset bit
records and daily reports. However, by incorporating other information
from mud logs, electric logs, the bit database analysis, final well
reports, etc., it allows a more precise analysis and optimum bit selec-
tion. Refer to “Hole section summaries” in Section 1.1.2, “Data
Acquisition and Analysis.”
The other data summary tool is field information notes. These give
a detailed (drilling) description of each formation to be encountered
and show problem areas, recommended bits, etc. It is particularly good
for drilling personnel new to an area if it incorporates the current state
of knowledge within the company on those formations. If a well is to
be planned where offset data is available but no in-depth analysis has
been done, it is extremely useful to take the time to work through each
formation and write these notes for reference. These can be appended
to the drilling program. Refer to “Field operational notes” in Section
1.1.2, “Data Acquisition and Analysis.”
Both the field information notes and the hole section summaries
should be updated after each well is drilled.

2.4.2. Evaluating Offset Well Drilling Data

Comparing bit records using the BITREX database. When com-
paring offset runs, it is important to compare a shorter, faster run
with a longer run at lower ROP and say which is the better run in the
same formations.

183