The tubing is divided into flat tubing(NU), thickened tubing (EU) and integral joint tubing (IJ).

• Flat tubing means that the end of the tubing is directly threaded and coupled without thickening. 

• Thickened tubing refers to the two ends after external thickening, then the car threads and with coupling. 

• Integral joint tubing refers to one end through the internal thickening of the external threads of the vehicle, the other

• end through the external thickening of the internal threads of the vehicle, directly connecting without

• coupling.

Function of tubing: 

• oil and gas extraction: After completion of well drilling and cementing, the tubing is placed in the casing of the reservoir to extract oil and gas to the surface. 

• Water injection: When the downhole pressure is insufficient, water is injected into the well through the tubing. Steam injection: In the process of heavy oil thermal recovery, heat insulation tubing is used to input steam into the well.

• Acidification and fracturing: In order to improve the production of oil and gas wells in the late stage of well drilling, acidizing and fracturing media or fixed-line substances need to be input into the reservoir, and the media or solidified substances are transported through the tubing.