Definition of oil casing

Oil pipes are mainly used for oil and gas well drilling and oil and gas transportation. It includes an oil drilling pipe, oil casing, and oil extraction pipe. Oil drill pipe is mainly used to connect drill collars and drill bits and transmit drilling power. The oil casing is mainly used to support the well wall during and after the well completion, to ensure the drilling process and the normal operation of the entire oil well after the well completion. The oil suction pipe mainly transports the oil and gas at the bottom of the oil well to the surface.

Oil casing is the lifeline to keep the oil well running. Due to the different geological conditions, the downhole stress state is complex, and the combined effects of tension, compression, bending, and torsional stress act on the pipe body, which puts forward higher requirements on the quality of the casing itself. Once the casing is damaged for some reason, it may lead to a reduction in production of the entire well, or even scrap it.

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 and well depths require different steel grades. In a 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.