Carbon Steel Tubing API 5CT N80 Oilwell Casing High Intensity​

Overwiew

Petroleum casing is a large-diameter pipe that serves to secure the wall or borehole of an oil and gas well. The casing is inserted into the borehole and cemented in place to prevent the borehole from separating rock and collapsing and to ensure circulation of mud for ease and extraction. Petroleum casing is the steel pipe that supports the wall of the tubing of an oil or gas well, in and well to ensure the proper functioning of the entire well. Several layers of casing are used in each well, depending on depth and geology. Cased wells should be cemented. It is not reusable unlike tubing and drill pipe. It is a one-time consumption material. Therefore, casing consumption accounts for more than 70% of the total consumption of oil tubing in oil wells.

Oil casing oil, natural gas and the transportation of oil and natural gas. It includes oil drill pipe, oil casing, and pumping machine pipe. Oil drill pipe connects the drill collar and drill bit and transmits power. Oil casing and the support of the well wall to ensure and the normal operation of the whole well. Sucker pipe is to transport oil and gas from the bottom of the well to the surface.

Petroleum casing is the lifeline of oil well operation. Due to the different geological conditions and complex underground stress state, the combined effects of tensile, compressive, bending and torsional stresses on the tubing body puts higher demands on the quality of the casing itself. If the casing itself is damaged for any reason, it may lead to production reduction or even abandonment of the whole well.

The casing can be categorized into different steel grades according to the strength of the steel itself, i.e., J55, K55, N80, L80, C90, T95, P110, Q125, V150 and so on. Petroleum casing steel grade: H40, J55, K55, N80, L80, C90, T95, P110, Q125, V150 and so on. Casing end face processing forms: short round thread, long round thread, trapezoidal thread, special snap, etc. And the well wall support to ensure the normal operation of the whole well after the end.

Different well conditions and depths require different grades of steel. The casing itself also requires corrosion resistance in corrosive environments. The casing also needs to be pressure resistant in places with complex geological conditions.27MnCrV is a new type of steel used in the production of TP110T steel casing.Conventional production of TP110T steel casing uses 29CrMo44 and 26CrMo4.Compared with the latter two, 27MnCrVMo has less elemental content, which can greatly reduce production costs. However, after using the normal austenitic quenching process to produce 27MnCrV, there is a significant high-temperature tempering brittleness, resulting in low and unstable impact toughness. In order to solve such problems, two methods are usually used:First, rapid cooling is used after tempering to avoid high temperature embrittlement and obtain toughness. Secondly, the sub-temperature quenching method can effectively improve the harmful elements and impurities through the incomplete austenitization of the steel to improve the toughness. The first method has more stringent requirements for heat treatment equipment, which adds extra cost.

Chemical Composition of API 5CT N80

Mechanical Properties of API 5CT N80

Production Casing Size of API 5CT N80

Applications

Drill

Gas

Boiler

Petroleum

Chemistry