Rotary Speed
Rotary speed should be relatively high, with 100 rpm being average,
although 200 to 1000 rpm is not uncommon when downhole motors are
used. Penetration rate should increase at high speeds if hydraulics are good
and no roughness in drilling occurs.
Drill rate, with good hydraulics, is nearly a straight line function of rotary
speed. Drilling rate will, therefore, continue to increase as rotary speed is
increased. The limits are usually imposed by safety considerations for the
drill pipe.
Rotary speed should be relatively high, with 100 rpm being average,
although 200 to 1000 rpm is not uncommon when downhole motors are
used. Penetration rate should increase at high speeds if hydraulics are good
and no roughness in drilling occurs.
Drill rate, with good hydraulics, is nearly a straight line function of rotary
speed. Drilling rate will, therefore, continue to increase as rotary speed is
increased. The limits are usually imposed by safety considerations for the
drill pipe.
