Description
Tubing Coupling
Normally tubing coupling OD maximum is 4 1/2”, as the tubing pipe is applied for the drilling activities (Inside the tubing is the sucker rod to drill/pump the oil), couplings type is more various and rigorous than casing, mostly used is thicken type upset coupling (Internal upset and external upset), for short is EUE coupling, it is the most favorable in tubing connections. Tubing with EU end (EUE) coupling connection also called UPTBG. Because of the end of the tubing is thickened (upset), the connecting stress is better than buttress coupling.
Buttress coupling another type used for tubing connections, it has the same thickness of the pipe body, called NU end (NUE)tubing or TBG.
Features
The oil tubing coupling can solve the problem of fatigue fracture in the existing coupling due to stress concentration. Oil tubing end is connected to the inside wall of the coupling in a tapered thread. The coupling body end and oil tubing are connected with same thread pitch flat thread. The coupling is not easy to produce fatigue fracture, and has good connection effect. It can prevent the accident of oil well pipe string break effectively.
Casing Coupling
Casing coupling is for the dimensions more than 4 1/2 inch. Differently than tubing coupling is, casing coupling normally does not need to be thickened (Non-upset), which means no upset casing coupling, so it has following types:
• BTC: Buttress coupling
• LTC: Long buttress coupling
• STC: Short buttress coupling
All three types has same thickness of the casing pipe body, just have different lengths.
The oil casing coupling is a necessary piece used to connect the two casing. The coupling manufacturing method is the same as seamless pipe. The steel pipe ends with internal thread to connect with the upper and lower casing. In order to ensure the joint tightness, the precision of screw thread is strictly required.
If you have any Inquiry, please don't hesitate to contact us immediately,Email:sales@union-steels.com
Specification
API Tubing Coupling
|
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
|
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
|
Standard
Applicable Standards of OCTG Couplings
API 5CT material for body;
API 5B for API threads;
Premium thread per licensor specifications
Main Technical Parameters of Coupling
Couplings
|
Size in
|
Max. OD in(mm)
|
Min length in(mm)
|
Grade
|
NU
|
EU
|
NU
|
EU
|
23/8
|
2.875(73.03)
|
3.063(77.80)
|
41/4(107.95)
|
47/8(123.83)
|
J55
N80
L80
|
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
|
All kinds of crossovers, connections and sub-couplings of grades J55, N80 and L80
|
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
|
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
|
Process
Packing
Standard
Applicable Standards of OCTG Couplings
API 5CT material for body;
API 5B for API threads;
Premium thread per licensor specifications
Main Technical Parameters of Coupling
Couplings
|
Size in
|
Max. OD in(mm)
|
Min length in(mm)
|
Grade
|
NU
|
EU
|
NU
|
EU
|
23/8
|
2.875(73.03)
|
3.063(77.80)
|
41/4(107.95)
|
47/8(123.83)
|
J55
N80
L80
|
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
|
All kinds of crossovers, connections and sub-couplings of grades J55, N80 and L80
|
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
|
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
|