The tubing in the oil casing is a pipeline that transports crude oil and natural gas from the oil and gas layer to the surface after the drilling is completed. The casing is a large-diameter pipe that is used to withstand the pressure generated during the mining process and to fix the oil and natural gas. The role of the well wall or borehole. Except for an additional thickening process for thickening the pipe wall, the production process of tubing is similar to that of casing.
The casing is inserted into the well hole and fixed with cement to prevent the well bore from collapsing between the rock strata and the well bore, and to ensure the circulation of drilling mud to facilitate drilling and exploitation.

The outer diameter of the tubing is generally 60.3 mm to 114.3 mm.

classification
Different types of casings used in the oil extraction process:
Surface oil casing
-Protect the drilling well to avoid contamination by shallow water and gas layers,
-Support wellhead equipment and maintain the weight of other layers of casing.
Technical oil casing
-Separate the pressure at different levels so that the drilling fluid can circulate normally and protect the production casing.
-In order to install anti-burst devices, leak-proof devices and tail pipes in the well.
Oil layer casing
-Export oil and natural gas from the reservoir below the surface.
-It is used to protect wells and layer drilling mud.
When the oil casing is produced, the outer diameter is usually 114.3 mm to 508 mm.