There are two main differences between oil casing and oil drill pipe: 1. Different uses; 2. Different materials.

Oil casing is a steel pipe used to support the well wall of oil and gas wells to ensure the normal operation of the entire oil well during the drilling process and after completion. Each well uses several layers of oil casing according to different drilling depths and geological conditions. After the oil casing is lowered into the well, cement is used for cementing. Unlike oil pipes and drill pipes, it cannot be reused and is a one-time consumable material. Therefore, the consumption of oil casing accounts for more than 70% of all oil well pipes. The oil casing can be divided into: guide tube, surface oil casing, technical oil casing, and oil layer oil casing according to its use.

Rods connected in drilling tools to transmit power. The common components of the drill string are: a drill bit, drill collar, drill pipe, stabilizer, special joint, and square drill pipe. The basic functions of the drill string are: (1) lifting and lowering the drill bit; (2) applying drilling pressure; (3) transmitting power; (4) conveying drilling fluid; (5) performing special operations: squeezing cement, handling underground accidents, etc.

API standard E75 to S135 steel grades, a series of oil drill pipes with outer diameters ranging from 2 3/8″ to 6 5/8″, as well as double-shoulder joint drill pipes with high torsion resistance and special steel grade BNK C95S drill pipes for sulfur-containing oil wells. Mainly used in the construction of deep wells, horizontal wells, and large-reach wells during oil and gas exploration and development.