Tubing and Casing Coupling
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 |
| Upset | Non UpsetExternal Upset |
| Grade | J-55, C-75, L-80, N-80, C-95, P-110 |
| Option | Electro-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 |
| Threading | Short Round-Thread Casing (STC)Long Round-Thread Casing (LC)Buttress Thread Casing (BC) |
| Grade | H-40, J-55, K-55, C-75, L-80, N-80, C-95, AS-95, P-110, L80-13CR |
|
API Tubing Coupling |
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| Descriptions and size | Type of Thread | O.D*L | Weight | |
| (mm) | (kg) | |||
| Tubing Coupling | 1.05 | NUE | 33.35*80.96 | 0.23 |
| 1.05 | EUE | 42.16*82.55 | 0.38 | |
| 1.315 | NUE | 42.16*82.55 | 0.38 | |
| 1.315 | EUE | 48.26*88.90 | 0.57 | |
| 1.66 | NUE | 52.17*88.90 | 0.59 | |
| 1.66 | EUE | 58.88*95.25 | 0.68 | |
| 1.9 | NUE | 55.88*95.25 | 0.56 | |
| 1.9 | EUE | 63.50*98.42 | 0.84 | |
| 2-3/8″ | NUE | 73.02*107.95 | 1.28 | |
| 2-3/8″ | EUE | 77.80*132.82 | 1.55 | |
| 2-7/8″ | NUE | 88.90*130.18 | 2.34 | |
| 2-7/8″ | EUE | 93.17*133.35 | 2.4 | |
| 3-1/2″ | NUE | 107.95*142.88 | 3.71 | |
| 3-1/2″ | EUE | 114.30*146.05 | 4.1 | |
| 4″ | NUE | 120.65*146.05 | 4.35 | |
| 4″ | EUE | 127.00*152.40 | 4.82 | |
| 4-1/2″ | NUE | 132.08*155.58 | 4.89 | |
| 4-1/2″ | EUE | 141.30*158.75 | 6.05 | |
|
API Casing Coupling |
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Descriptions and size |
Type of Thread |
O.D*L |
Weight |
|
|
(mm) |
(kg) |
|||
|
Casing Coupling |
4-1/2″ |
STC |
127.00*158.75 |
5.23 |
|
4-1/2″ |
LTC |
127.00*177.80 |
4.15 |
|
|
4-1/2″ |
BTC |
127.00*225.42 |
4.55 |
|
|
5″ |
STC |
141.30*165.10 |
4.66 |
|
|
5″ |
LTC |
141.30*196.85 |
5.75 |
|
|
5″ |
BTC |
141.30*231.78 |
5.85 |
|
|
5-1/2″ |
STC |
153.67*171.45 |
5.23 |
|
|
5-1/2″ |
LTC |
153.67*203.20 |
6.42 |
|
|
5-1/2″ |
BTC |
153.67*234.95 |
6.36 |
|
|
6-5/8″ |
STC |
187.71*184.15 |
9.12 |
|
|
6-5/8″ |
LTC |
187.71*222.25 |
11.34 |
|
|
6-5/8″ |
BTC |
187.71*244.48 |
11.01 |
|
|
7″ |
STC |
194.46*184.15 |
8.39 |
|
|
7″ |
LTC |
194.46*228.60 |
10.83 |
|
|
7″ |
BTC |
194.46*254.00 |
10.54 |
|
|
7-5/8″ |
STC |
215.90*190.50 |
12.3 |
|
|
7-5/8″ |
LTC |
215.90*234.95 |
15.63 |
|
|
7-5/8″ |
BTC |
215.90*263.52 |
15.82 |
|
|
8-5/8″ |
STC |
244.48*196.85 |
16.23 |
|
|
8-5/8″ |
LTC |
244.48*254.00 |
21.67 |
|
|
8-5/8″ |
BTC |
244.48*269.88 |
20.86 |
|
|
9-5/8″ |
STC |
269.88*196.85 |
18.03 |
|
|
9-5/8″ |
LTC |
269.88*266.70 |
25.45 |
|
|
9-5/8″ |
BTC |
269.88*269.88 |
23.16 |
|
|
10-3/4″ |
STC |
298.45*203.20 |
20.78 |
|
|
10-3/4″ |
BTC |
298.45*269.88 |
25.74 |
|
|
11-3/4′ |
STC |
323.85*203.20 |
22.64 |
|
|
11-3/4′ |
BTC |
323.85*269.88 |
28.03 |
|
|
13-3/8″ |
STC |
365.12*203.20 |
25.66 |
|
|
13-3/8″ |
BTC |
365.12*269.88 |
31.77 |
|
|
16″ |
STC |
431.80*228.6 |
34.91 |
|
|
16″ |
BTC |
431.80*269.88 |
40.28 |
|
|
18-5/8″ |
STC |
508.00*228.60 |
51.01 |
|
|
18-5/8″ |
BTC |
508.00*269.88 |
62.68 |
|
|
20″ |
STC |
533.40*228.6 |
43.42 |
|
|
20″ |
LTC |
533.4*292.10 |
57.04 |
|
|
20″ |
BTC |
533.40*269.88 |
50.1 |
|
Applicable standards:
API 5CT material for body;
API 5B for API threads;
Premium thread per licensor specifications
Main Technical parameters
|
Couplings |
Size in |
Max. OD in(mm) |
Min length in(mm) |
Grade |
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|
NU |
EU |
NU |
EU |
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|
23/8 |
2.875(73.03) |
3.063(77.80) |
41/4(107.95) |
47/8(123.83) |
J55 N80 |
|
|
|
27/8 |
3.500(88.90) |
3.668(93.20) |
51/8(130.18) |
51/4(133.35) |
|
|
|
31/2 |
4.250(108.00) |
4.500(114.30) |
55/8(142.88) |
53/4(146.05) |
|
|
Crossovers |
J55,N80,L80 All kinds of crossovers, connections and sub-couplings of grades J55, N80 and L80 |
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COUPLING PIPE GRADE IDENTIFICATION BY PAINT COLOR
According to API 5CT standards, Oil casing and Tubing couplings should be painted one by one to distinguish different grades of steel. The color label of the oil casing and Tubing should be sprayed at any end ≥ 600mm, and the color should be painted on the whole outer surface, and then the color ring should be sprayed.
| Coupling colour code | |||||
| Grade | Grade Type | Colour(s) for Coupling | Number andcolour of bandsfor product | Picture | |
| EntireCoupling | Band(s) | ||||
| H40 | None | Same as for pipe | None/black band at the manufacturer’s option |  |
|
| J55 Tubing | Bright Green | None | One Bright Green |  |
|
| J55 Casing | Bright Green | One White | One Bright Green |  |
|
| K55 | Bright Green | None | Two Bright Green |  |
|
| M65 | M65Pipe uses L80Type 1Couplings | One Bright GreenOne Blue |  |
||
| N80 | 1 | Red | None | One Red |  |
| N80 | Q | Red | One Green | One RedOne Bright Green |  |
| R95 | Brown | None | One Brown |  |
|
| L80 | 1 | Red | One Brown | One RedOne Brown |  |
| L80 | 9Cr | None | Two Yellow | One Red,One Brown,Two Yellow |  |
| L80 | 13Cr | None | One Yellow | One Red,One Brown,One Yellow |  |
| C90 | 1 | Purple | None | One Purple |  |
| T95 | 1 | Silver | None | One Silver |  |
| C110 | White | Two Brown | One White,Two Brown |  |
|
| P110 | White | None | One White |  |
|
| Q125 | Orange | None | One Orange |  |
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