Page 37 - Practical Well Planning and Drilling Manual

Section 1 revised 11/00/bc 1/17/01 2:55 PM Page 13

Preliminary Work for the Well Design [ ]
1.1.2

these fractures as they were drilled, mud density was minimized, no
wipertrips were done, and the drillers were briefed on good tripping
and connection practices to minimize surge and swab pressures. This
strategy was successful and the Pliocene shales were drilled and cased
quickly using a KCl-PHPA-Glycol mud with only minor cavings. There
were no problems tripping or running casing.
Field operational notes. Daily drilling reports often leave a lot of
relevant information unrecorded. Drilling programs rarely give suffi-
cient information to the drilling supervisor about the formations
he/she is expected to drill through. Both these concerns can be over-
come by writing and updating field operational notes.
All the available data relating to each formation should be sum-
marized for future reference when planning and drilling. These should
be kept up to date. The following example of field operational notes are
from an actual operations manual (see Fig. 1-2). It can be seen that
there is much useful information to aid in bit selection and use, mud
parameters, and drilling practices.

These notes were allowed into the public domain with the kind permission of
the Badr Petroleum Company, Egypt (BAPETCO).

Formation Name: Abu Roash Type: Limestone + shale interbeds
Principal Problems: Lost circulation, shale cavings, hydration
swelling, gauge wear, and washouts

The Abu Roash formation presents a delicate problem. Too much
density + ECD with KCl polymer muds lead to losses (probably in the
limestone) but the mud density needed to minimize losses causes
shale cavings. Tight control of mud parameters and drilling practices
is needed. Ideally keep the density between 0.48-0.50 (maximum), PV
as low as possible (10-15), YP in the range 17-21, and gels 3/5 to 5/8.
Avoid surging on trips or after connections and minimize ECD. It is
possible to live with the cavings, keep the hole clean, have low hole
drags, and have few loss problems. If the hole was to be kicked off
higher up, increasing hole angle would lead to problems of
cuttings/cavings beds forming and consequent hole cleaning difficul-
Fig. 1-2 Example of Field Operational Notes

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