When the liquid products intended to be extracted from underground are reached, Tubing pipes of smaller diameter are lowered into the well through the casing wall pipes. Especially in oil production, the oil at the bottom of the well is raised up through the tubing pipes with the pump connected to the head which we call horse head running up and down continuously.
Tubing pipe diameters are used in diameters from 1.05 ”(Ø26.7 mm) to 4-1 / 2” (Ø114.3 mm) according to API standard. The same steel materials used in casings can also be used in these pipes. Depending on the loads to be carried according to the depths of use of tubing pipes, the blowing process called Upset can be applied to the pipe ends in order to strengthen the thread bottoms. Thicker threads can be made at the end of the upset pipes, thereby increasing both strength. Tubing pipes are divided into 2 groups as Non-Ups Straight End (NU) type and Outward Inflated End (EU).