Page 97 - Air and Gas Drilling Manual

Chapter 3: Downhole Equipment 3-25
axial tension is the pipe body. Column (11) gives a torque of 55,453 ft-lb to give
torsion yield of the steel of the pipe body and Column (12) gives a torque of 44,673
ft-lb to give torsion yield of the steel of the tool joint box. Thus, the weakest part
of the drill pipe element to torque is the pipe body.
Table B-6 gives a summary of the API connections available for both drill
collars and drill pipe. These connections are all API recognized and are used by a
variety of fabricators of drill collars and drill pipe. The table gives the outside
diameter, inside diameter, and thread data for each connection type and size. Also
given are the detailed dimensions of the box and pin of each connection. These
dimensions are not used in machining box and pin connections. Readers are referred
to Reference 6 to obtain information regarding API connection dimensions and
tolerances for machine shop.
3.4.2 Heavy-Weight Drill Pipe
Heavy-weight drill pipe is an intermediate weight per unit length drill string
element. This type of drill pipe has a heavy wall pipe body with attached extra
length tool joints (see Figure 3-21). Heavy-weight drill pipe has the approximate
outside dimensions of standard drill pipe to allow easy handling on the drill rig [6].

Figure 3-21: Heavy-weight drill pipe standing in rig rack (courtesy of Smith
International).