General Diamond Bit Drilling Practices

General Diamond Bit Drilling Practices
Prior to running a diamond bit, clean the hole by running a junk basket on
the last roller cone bit.
Running a Diamond Bit into the Hole
Place the bit in the bit breaker and makeup with tongs on the collar, to the
same torque as used on the collar connection.
Use care going in the hole. Avoid striking ledges and pushing through tight
places which could damage the gauge diamonds.
Although diamond bits may be used to ream short intervals, care must be
taken, especially the first time a diamond bit is run. Remember, diamond
bits are solidly constructed and have no “give” as do roller cone bits. In a
reaming situation, most of the drilling fluid escapes through the junk slots
on the diamond bit and the mud cannot effectively cool the diamonds in the
gauge zone. During reaming, these diamonds absorb all applied weight and
may become overloaded.
When reaming, the bit weight of about 2,000 to 5,000 pounds maximum
should be used to avoid fracturing or burning the diamonds, and the rotary
speed should be moderate (40-60 rpm). If considerable reaming in hard,
abrasive formations is going to be necessary, the diamond bit should be
pulled and replaced with a diamond bit specifically designed for reaming.