API J55 seamless steel pipe casing pipe

The steel grades of common oilfield API-5CT casing pipe include J55, K55, N80-1, N80Q, and P110. Casing pipe is mostly used for oil well drilling. In accordance with API-5CT and ISO 9001 standard, pipes can be classified as STC (short thread), LTC (long thread) and BTC (buttress thread) accompanied with their couplings.



Oilfield casing pipes are positioned into well bore and cemented in place to secure both subsurface formations and the wellbore from collapsing, also to enable drilling mud to circulate and extraction to take place. Casing pipes are normally manufactured using outside dimension sizes from 114.3 mm to 508.0 mm.



The strict quality requirement for steel is due to the harsh working conditions of casing. The steel product should be produced and checked in accordance with special standards or specifications. ISO 11960 and API Spec 5CT have specified the steel product standards of casing.



API non-upset (NUE) tubing is put to use much less than EUE tubing.



The cost of NUE is usually just a bit less than EUE, along with the joint strength is substantially less. The coupling joint diameter of NUE is less than EUE, which provides certain benefits in cases where clearance is small.



API NUE joints are available in sizes of 1.050 to 4.500 inch.The API external-upset-end (EUE) tubing pipe is broadly used due to the fact that is a good, serviceable interconnection in the majority of wells.



Without the need of modifying the actual thread shape, the joint dimension will increase because of upsetting procedure. The EUE joint features a designed joint strength in tension and pressure strength much higher than that of the pipe overall body and, as a result, is considered a 100% joint effective connection.



To enhance seal efficiency of API EUE tubing in high-pressure system, a grooved coupling, which accepts nonmetallic seal rings, is quite often applied in the coupling (see API Spec. 5CT SR 13).



API EUE joints come in OD sizes of 1.050 to 4.500 inch.