Oil casing
Oil casing is a steel pipe used to support the wall of oil and gas Wells to ensure the normal operation of the whole well during the drilling process and after the completion of the well. Each well uses several layers of casing, depending on the drilling depth and geology. Cement cementing should be used after casing Wells. It is different from tubing and drill pipe, and can not be reused. It is a one-time consumption material. Therefore, casing consumption accounts for more than 70% of the total oil well tubing.
Casing can be classified according to the usage: conduit, surface casing, technical casing and reservoir casing.
Petroleum special pipe is mainly used for oil, gas well drilling and oil, gas transportation. It includes oil drill pipe, oil casing, pumping pipe. The oil drill pipe is mainly used to connect the drill collar to the drill bit and transfer drilling power. The oil casing is mainly used to support the well wall during the drilling process and after the completion of the well, so as to ensure the drilling process and the normal operation of the whole well after the completion. The pumping pipe mainly carries oil and gas from the bottom of the well to the surface.
Oil casing is the lifeline of oil well operation. Due to the different geological conditions, the underground stress state is complex, and the comprehensive action of tensile, compressive, bending and torsional stresses on the pipe body puts forward higher requirements for the quality of the casing itself. If the casing itself is damaged for any reason, it can lead to the loss of production or even abandonment of 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. Different well conditions, well depth, the use of steel grade is also different. The casing itself is also required to have corrosion resistance in a corrosive environment. The casing is also required to be resistant to crush in places with complex geological conditions.