Classification of Oil Casing Pipes

The oil casing is used to support the oil and gas well wall to ensure the normal operation of the whole well after the completion of the drilling process. Each well is based on different drilling and geological depths, and multi-layer casing is used. Cement will be cemented after the casing is set down. It is different from tubing and drill pipe and cannot be reused. It's a disposable material. Therefore, the consumption of casing accounts for more than 70% of all oil well pipes.


The special oil pipe is mainly used for drilling oil and gas wells and transporting oil and gas. It includes oil drill pipe, oil casing and oil pipe. The oil drill pipe is mainly used to connect the drill collar and the drill bit and transfer the drilling power. The oil casing is mainly used to support the well wall in the process of drilling and after completion to ensure the normal operation of the whole well in the process of drilling and after completion. The tubing mainly transports the oil and gas at the bottom of the well to the surface.


Oil casing is the lifeline to maintain oil well operation. Due to different geological conditions, the downhole state is complex, and the joint action of tensile force, compression, bending and torsional stress acts on the pipe body, which puts forward high requirements for the quality of the casing itself. Once the casing itself is damaged for some reason, it may lead to a decline in production, or even scrap the whole well.


According to the strength of the steel itself, the casing can be divided into different steel grades, namely J55, K55, N80, L80, C90, T95, P110, q125, V150, etc. The condition and depth of the well are different, so are the steel grades used. It is also required that the shell itself has corrosion resistance in corrosive environment. It is also required that the casing has the ability of breaking resistance in the place with complex geological conditions.