Page 94 - Air and gas Drilling Field Guide 3rd Edition

4.4 Drill Pipe 85

STANDS BACK IN THE
RACK LIKE REGULAR
DRILL PIPE

WEAR PAD REDUCES THE
WEAR ON CENTER
SECTION OF DRILL PIPE

FIGURE 4-21. Heavyweight drill pipe standing in rig rack (courtesy of Smith International).

In off-shore drilling operations, heavyweight drill pipe has become essential.
Heavyweight drill pipe is used in directional drilling operations where drill collars
can be replaced by the heavyweight pipe. Using heavyweight drill pipe in place
of drill collars reduces the rotary torque and drag and increases directional control.
7
In Tables 4-3a and 4-3b there is an unusual drill pipe size. This is the 5 8 = -in
(149 mm) heavyweight drill pipe, and its associated standard drill pipe companion
is used for drilling long reach highly deviated directional boreholes (particularly
in offshore operations). This drill pipe allows higher annulus drilling fluid velocities
for improved cuttings removal (particularly in horizontal boreholes) and lower
drilling fluid velocities inside the drill string to reduce pipe friction losses.