Page 210 - Practical Well Planning and Drilling Manual

Section 2 revised 11/00/bc 1/17/01 12:04 PM Page 186

[ ] Well Programming
2.4.2

This quick evaluation could form the basis for our bit selection on
the next Obaiyed well by simply using the best performing bit to date
in each formation. However, what we should do is try to establish
which bit will improve on the previous best run. For that, we have to
do further analysis.
Writing field information notes for bit runs. Daily drilling reports
often leave a lot of relevant information unrecorded. Drilling programs
rarely give sufficient information to the drilling supervisor about the
anticipated formations. Both these concerns can be overcome by writing
and updating field information notes.
As operations proceed, the on-site drilling supervisors should
make detailed notes of operational events. At the end of a hole section,
the drilling supervisors should use these notes to write a detailed
report, which can be incorporated into the final well report. An exam-
ple is shown in Section 1.1, “Preliminary Work for the Well Design.”
This information should also be used to add to or amend the field
information notes. The information that is required in particular is:

Details and comments on each bit run
Any problems that were experienced and how they were solved
Suggestions for improvements to the bit program for drilling the
next well

All the available data relating to each formation can then be sum-
marized for future reference when planning and drilling. As experience
is gained, this data should be kept up to date. It can be seen that there
is much useful information to aid in bit selection and use.
Mud log. If a logging unit is on-site, it is worth getting the loggers
to record drilling data every foot or meter in a format that can be
imported into a spreadsheet. This allows the drilling engineer to make
very detailed analyses. As shown on the hole section summary, the
ROP data with changes of bit or formation that came from the mud log-
ger’s data (recorded every meter). By correlating with wireline logs, a
comprehensive picture can be built. The data recorded in the spread-
sheet was:
Depth in 1 m intervals
Drilling rate in both minutes per meter and meters per hour
Weight on bit

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