Coupling for petroleum casing pipe


Tubing coupling is a kind of drilling tool available in oil field. Tubing couplings are mainly used in connecting oil pipes. This type of pipe coupling has handled the problem that the existing couplings tend to crack because of stress concentration. The oil pipe ends and the inner wall of the tubing coupling are connected by threads. And the oil pipes and the ends of the tubing coupling have the same type of threads. It is not easy to crack for this type of connection and the connection effect is good. The tubing coupling can avoid the oil well string dropout accident effectively.

Casing coupling is a short pipe applied in connecting two casing pipes which have threads. The pipe coupling has internal threads machined to match the external thread of the long joints of casing. The two joints of casing pipes are screwed into opposite ends of the casing coupling. Through their strength can be normally made of the same grade of steel as the casing. All casing couplings are manufactured in accordance with API 5CT specification of the latest edition.

Properties of Casing Couplings:
♦ The material of casing couplings is H40, J55, K55, M65, N80-1, N80Q, L80, C95, T95 and P110 grade steel with high quality and good performance;
♦ The outer diameter ranges from 127mm to 365.12 mm;
♦ The casing couplings thread patterns include short round thread, long round thread and buttress thread.

Tubing coupling is a kind of drilling tool available in oil field. Tubing couplings are mainly used in connecting oil pipes. This type of pipe coupling has handled the problem that the existing couplings tend to crack because of stress concentration. The oil pipe ends and the inner wall of the tubing coupling are connected by threads. And the oil pipes and the ends of the tubing coupling have the same type of threads. It is not easy to crack for this type of connection and the connection effect is good. The tubing coupling can avoid the oil well string dropout accident effectively.

Properties of Tubing Coupling:
♦ The material of tubing couplings is H40, J55, N80-1, N80Q, L80, C90, T95 and P110 grade steel with high quality and good performance;
♦ It is mainly used to connect two oil pipes;
♦ The tubing coupling thread patterns include non-upset thread and upset thread;
♦ The outer diameter of tubing coupling ranges from 55.88 mm to 141.3 mm;

API Tubing Coupling

Specification
Size (Pipe OD) (in)1.900, 2-3/8, 2-7/8, 3-1/2, 4, 4-1/2
UpsetNon UpsetExternal Upset
GradeJ-55, C-75, L-80, N-80, C-95, P-110
OptionElectro-zinc platedPhosphorised

API Casing Coupling

Specification
Size (Pipe OD) (in)4-1/2, 5, 5-1/2, 6-5/8, 7, 7-5/8, 8-5/8, 9-5/8, 10-3/4, 11-3/4, 13-3/8, 16, 18-5/8, 20
ThreadingShort Round-Thread Casing (STC)Long Round-Thread Casing (LC)Buttress Thread Casing (BC)
GradeH-40, J-55, K-55, C-75, L-80, N-80, C-95, AS-95, P-110, L80-13CR