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Steel classification – petroleum casing

Oil casing is a seamless steel pipe used to support the well wall of oil and gas wells to ensure the normal operation of the whole oil well during the drilling process and after completion. Several layers of casing shall be used for each well according to different drilling depth and geological conditions. Cement shall be used for cementing after casing running. It is different from oil pipe and drill pipe and cannot be reused. It is a disposable consumable material. Therefore, the consumption of casing pipe accounts for more than 70% of all oil well pipes.

Special oil pipes are mainly used for oil and gas well drilling and oil and gas transmission. It includes oil drilling pipe, oil casing and oil extraction pipe. Oil drill pipe is mainly used to connect drill collar and drill bit and transfer drilling power. The oil casing is mainly used to support the well wall during drilling and after well completion, so as to ensure the drilling process and the normal operation of the whole oil well after well completion. The oil extraction pipe mainly transports the oil and gas at the bottom of the oil well to the surface.

Oil casing is the lifeline to maintain oil well operation. Due to different geological conditions, the downhole stress state is complex, and the tensile, compressive, bending and torsional stresses act on the pipe body, which puts forward higher requirements for the quality of the casing itself. Once the casing itself is damaged for some reason, the production of the whole well may be reduced or even scrapped.

According to the strength of the steel itself, the casing can be divided into different steel grades, namely H40, J55, K55, N80, L80, C90, T95, P110, q125, V150, etc. the main specifications are 139.77*72r-2 177.89*19r-2 244.58*94r-2 244.5*10.03r-2 244.5*11.05r-2, etc. Different steel grades are adopted for different well conditions and well depths. In corrosive environment, the casing itself is also required to have corrosion resistance. In places with complex geological conditions, the casing is also required to have anti collapse performance.

Processing forms of oil casing end: short round thread, long round thread, trapezoidal thread, special buckle, etc. It is mainly used to support the well wall during drilling and after completion, so as to ensure the drilling process and the normal operation of the whole oil well after completion.


Post time: Jun-14-2022