In order to enhance the connection strength of the tube body and the joint, the two ends of the tube body are thickened. The commonly used thickening forms are internal thickening, external thickening and internal and external thickening. According to the American Petroleum Institute (API), drill pipe is divided into three categories by length:
The first type, 5.486~6.706m(18~22ft);
The second type, 8.230~9.144m(27~30ft);
The third type, 11.582~13.716m(38~45ft);
The most commonly used drill pipe sizes are 88.9(3.5in), 114.3(4in), and 127.0mm(5.5in).
How is the drill pipe classified by length? (figure 1)
△ Drill pipe thickening form
The outer diameter of the drill pipe joint is larger than the outer diameter of the pipe body. In the drilling process, it constantly contacts and frictions with the borehole wall or casing, resulting in wear and tear. In order to avoid drilling accidents such as broken drill pipe and tripping caused by joint wear, the drill pipe joint anti-wear belt must be provided on the drill pipe parent joint.
How is the drill pipe classified by length? (figure 2)
△ Joint wear belt