Patent attributes
A drill pipe 10 comprises an elongate pipe section 12 having a substantially uniform pipe outer diameter 18 and a substantially uniform pipe inner diameter 20. A pin tool joint 14 is welded at one end to the pipe section, and a box tool joint 16 is welded to the other end of the pipe section. Each of the pin and box tool joints includes a thread for mating engagement and preferably first and second shoulders. The drill pipe has a ratio, R, which takes into consideration the pipe inner diameter, PID, the pipe outer diameter, POD, the tool joint inner diameter, TJID, and the tool joint outer diameter, TJOD. This ratio may be expressed as:R=(PID+TJID)(TJOD-POD).According to the present invention, this ratio is greater than 8.0, and is preferably from 8.1 to 8.5, thereby providing a drill pipe with desired strength and fluid flow capabilities.
