Page 160 - Drilling Technology in Nontechnical Language

Chapter 6 – DRILL BITS 151

Fig. 6–8. Broken TCI cutters

One problem with dull bit grading is that different people will tend
to give slightly different gradings to the same bit. This is mostly because
some do not properly recognize the important dull features. It is a very
good idea for all dull bits to be photographed, and the photo kept in the

files relating to the well, so that questions about the grading later on might
be resolved.

Bit Selection

There are many different drill bits to choose from. Good bit selection
is vital to achieve the best drilling performance and therefore to reduce the
cost of drilling.

_Devereux_Book.indb 151 1/16/12 2:09 PM