Tubing couplings are a type of oilfield drilling tool used primarily for tubing connections. The tubing coupling mainly solves the problem that the existing coupling is easily broken due to stress concentration.
The tubing coupling structure is: the tubing end is connected to the inner wall of the coupling by a taper thread, and the end of the coupling body and the oil pipe are connected by the same thread with the pitch flat thread. The utility model has the characteristics of alleviating the stress concentration of the root of the external thread of the single taper thread connection tubing, is not easy to produce fatigue fracture, and has good connection effect. Effectively prevent oil well pipe string breakage accidents.
The coupling is divided into a tubing coupling and a casing coupling. Commonly used steel grades are J55, K55, N80, L80, P110 and so on.