API 5CT Casing and Tubing
API 5CT Casing and Tubing
Introduction
API 5CT is a specification developed by the American Petroleum Institute (API) for casing and tubing materials used in the oil and gas industry. It covers a range of steel grades designed to meet various operational and environmental challenges. These materials are critical for drilling and production operations, providing structural integrity and transport pathways within the wellbore.
Key Components
Casing
Casing is a large-diameter pipe inserted into a drilled well and cemented in place to provide structural integrity and isolate different subsurface zones.
- Conductor Casing: The first casing run to protect the well from surface water.
- Surface Casing: Prevents caving and isolates shallow water zones.
- Intermediate Casing: Isolates formations and stabilizes the well.
- Production Casing: Ensures the integrity of the well during the production phase.
Tubing
Tubing is a smaller-diameter pipe placed inside the casing to transport hydrocarbons from the reservoir to the surface.
- Production Tubing: Conveys oil and gas to the surface.
- Injection Tubing: Used for injecting fluids into the well.
Standards and Grades
API 5CT specifies various grades of casing and tubing, each tailored for different environmental and operational conditions. Key grades include:
- H40, J55, K55: Basic grades for standard drilling operations.
- N80, L80, C90: Higher strength grades for deeper and more challenging wells.
- T95, P110, Q125: High-strength grades for ultra-deep and high-pressure environments.
- V150: The highest strength grade for the most extreme conditions.
O.D: 4 1/2″-20″
Length: R1, R2, R3
Connection: STC, LTC, BTC, Premium Connection (VAM TOP, NEW VAM, PH-6)
Casing Pipe Data Table
| Labels a | OD mm |
Nominal Linear Mass b,c T&C kg/m |
WT t mm |
Type of end-finish d | ||||||||
| H40 | J55 K55 |
M65 | L80 R95 |
N80 Type 1, Q |
C90 T95 |
P110 | Q125 | |||||
| 1 | 2 | |||||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| 4-1/2 4-1/2 4-1/2 4-1/2 4-1/2 |
9.50 10.50 11.60 13.50 15.10 |
114.30 114.30 114.30 114.30 114.30 |
14.14 15.63 17.26 20.09 22.47 |
5.21 5.69 6.35 7.37 8.56 |
PS – – – – |
PS PSB PSLB – – |
PS PSB PLB PLB – |
– – PLB PLB – |
– – PLB PLB – |
– – PLB PLB – |
– – PLB PLB PLB |
– – – – PLB |
| 5 5 5 5 5 5 5 |
11.50 13.00 15.00 18.00 21.40 23.20 24.10 |
127.00 127.00 127.00 127.00 127.00 127.00 127.00 |
17.11 19.35 22.32 26.79 31.85 34.53 35.86 |
5.59 6.43 7.52 9.19 11.10 12.14 12.70 |
– – – – – – – |
PS PSLB PSLBE – – – – |
PS PSLB PLB PLB PLB – – |
– – PLB PLB PLB PLB PLB |
– – PLB PLB PLB PLB PLB |
– – PLB PLB PLB PLB PLB |
– – PLB PLB PLB PLB PLB |
– – – PLB PLB PLB PLB |
| 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 5-1/2 |
14.00 15.50 17.00 20.00 23.00 26.80 29.70 32.60 35.30 38.00 40.50 43.10 |
139.70 139.70 139.70 139.70 139.70 139.70 139.70 139.70 139.70 139.70 139.70 139.70 |
20.83 23.07 25.30 29.76 34.23 39.88 44.20 48.51 52.53 56.55 60.27 61.14 |
6.20 6.98 7.72 9.17 10.54 12.70 14.27 15.88 17.45 19.05 20.62 22.22 |
PS – – – – – – – – – – – |
PS PSLBE PSLBE – – – – – – – – – |
PS PSLB PLB PLB PLB – – – – – – – |
– – PLBE PLBE PLBE – – – – – – – |
– – PLBE PLBE PLBE – – – – – – – |
– – PLBE PLBE PLBE P P P P P P P |
– – PLBE PLBE PLBE – – – – – – – |
– – – – PLBE – – – – – – – |
| 6-5/8 6-5/8 6-5/8 6-5/8 |
20.00 24.00 28.00 32.00 |
168.28 168.28 168.28 168.28 |
29.76 35.72 41.67 47.62 |
7.32 8.94 10.59 12.06 |
PS – – – |
PSLB PSLBE – – |
PSLB PLB PLB – |
– PLBE PLBE PLBE |
– PLBE PLBE PLBE |
– PLBE PLBE PLBE |
– PLBE PLBE PLBE |
– – – PLBE |
| 7 7 7 7 7 7 7 |
17.00 20.00 23.00 26.00 29.00 32.00 35.00 |
177.80 177.80 177.80 177.80 177.80 177.80 177.80 |
25.30 29.76 34.23 38.69 43.16 47.62 52.09 |
5.87 6.91 8.05 9.19 10.36 11.51 12.65 |
PS PS – – – – – |
– PS PSLBE PSLBE – – – |
– PS PLB PLB PLB PLB – |
– – PLB PLB PLB PLB PLB |
– – PLB PLB PLB PLB PLB |
– – PLB PLB PLB PLB PLB |
– – – PLB PLB PLB PLBE |
– – – – – – PLB |
| 7 7 7 7 7 7 |
38.00 42.70 46.40 50.10 53.60 57.10 |
177.80 177.80 177.80 177.80 177.80 177.80 |
56.55 63.54 69.05 74.56 79.77 84.97 |
13.72 15.88 17.45 19.05 20.62 22.22 |
– – – – – – |
– – – – – – |
– – – – – – |
PLB – – – – – |
PLB – – – – – |
PLB P P P P P |
PLB – – – – – |
PLB – – – – – |
| 7-5/8 7-5/8 7-5/8 7-5/8 7-5/8 7-5/8 7-5/8 7-5/8 7-5/8 7-5/8 |
24.00 26.40 29.70 33.70 39.00 42.80 45.30 47.10 51.20 55.30 |
193.68 193.68 193.68 193.68 193.68 193.68 193.68 193.68 193.68 193.68 |
35.72 39.29 44.20 50.15 58.04 63.69 67.41 70.09 76.19 82.30 |
7.62 8.33 9.52 10.92 12.70 14.27 15.11 15.88 17.45 19.05 |
PS – – – – – – – – – |
– PSLB – – – – – – – – |
– PSLB PLB PLB – – – – – – |
– PLB PLB PLB PLB PLB PLB PLB – – |
– PLB PLB PLB PLB PLB PLB PLB – – |
– PLB PLB PLB PLB PLB PLB PLB P P |
– – PLB PLB PLB PLB PLB PLB – – |
– – – – PLB PLB PLB PLB – – |
| 7-3/4 | 46.10 | 196.85 | 68.60 | 15.11 | – | – | – | P | P | P | P | P |
| 8-5/8 8-5/8 8-5/8 8-5/8 8-5/8 8-5/8 8-5/8 |
24.00 28.00 32.00 36.00 40.00 44.00 49.00 |
219.08 219.08 219.08 219.08 219.08 219.08 219.08 |
35.72 41.67 47.62 53.57 59.53 65.48 72.92 |
6.71 7.72 8.94 10.16 11.43 12.70 14.15 |
– PS PS – – – – |
PS PS – PSLB PSLB PLB – |
PS PS PSLB PSLB PLB – – |
– – – PLB PLB PLB PLB |
– – – PLB PLB PLB PLBE |
– – – PLBE PLBE PLBE PLBE |
– – – PLB PLB PLB |
– – – – – PLB |
| 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 9-5/8 |
32.30 36.00 40.00 43.50 47.00 53.50 58.40 59.40 64.90 70.30 75.60 |
244.48 244.48 244.48 244.48 244.48 244.48 244.48 244.48 244.48 244.48 244.48 |
48.07 53.57 59.53 64.73 69.94 79.62 86.91 88.40 96.58 104.62 112.50 |
7.92 8.94 10.03 11.05 11.99 13.84 15.11 15.47 17.07 18.64 20.24 |
PS PS – – – – – – – – – |
– PSLB PSLB – – – – – |
– PSLB PSLB PLB PLB – – – – – |
– – PLB PLB PLB PLB PLB – – – – |
– – PLB PLB PLB PLB PLB – – – |
– – PLB PLB PLB PLB PLB P P P P |
– – – PLB PLB PLB PLB – – – – |
– – – – PLB PLB PLB – – – – |
| 10-3/4 10-3/4 10-3/4 10-3/4 10-3/4 10-3/4 10-3/4 10-3/4 10-3/4 10-3/4 |
32.75 40.50 45.50 51.00 55.50 60.70 65.70 73.20 79.20 85.30 |
273.05 273.05 273.05 273.05 273.05 273.05 273.05 273.05 273.05 273.05 |
48.74 60.27 67.71 75.90 82.59 90.33 97.77 108.93 117.86 126.94 |
7.09 8.89 10.16 11.43 12.57 13.84 15.11 17.07 18.64 20.24 |
PS PS – – – – – – – – |
– PSB PSB PSB – – – – – – |
– PSB PSB PSB PSB – – – – – |
– – – PSB PSB – – – – – |
– – – PSB PSB – – – – – |
– – – PSB PSB PSB PSB P P P |
– – – PSB PSB PSB PSB – – – |
– – – – – PSB PSB – – – |
| 11-3/4 11-3/4 11-3/4 11-3/4 11-3/4 11-3/4 |
42.00 47.00 54.00 60.00 65.00 71.00 |
298.45 298.45 298.45 298.45 298.45 298.45 |
62.50 69.94 80.36 89.29 96.73 105.66 |
8.46 9.53 11.05 12.42 13.56 14.78 |
PS – – – – – |
– PSB PSB PSB – – |
– PSB PSB PSB – – |
– – – PSB P P |
– – – PSB P P |
– – – PSB P P |
– – – PSB P P |
– – – PSB P P |
| 13-3/8 13-3/8 13-3/8 13-3/8 13-3/8 |
48.00 54.50 61.00 68.00 72.00 |
339.72 339.72 339.72 339.72 339.72 |
71.43 81.10 90.78 101.19 107.15 |
8.38 9.65 10.92 12.19 13.06 |
PS – – – – |
– PSB PSB PSB – |
– PSB PSB PSB – |
– – – PSB PSB |
– – – PSB PSB |
– – – PSB PSB |
– – – PSB PSB |
– – – – PSB |
| 16 16 16 16 |
65.00 75.00 84.00 109.00 |
406.40 406.40 406.40 406.40 |
96.73 111.61 125.01 162.21 |
9.53 11.13 12.57 16.66 |
PS – – – |
– PSB PSB P |
– PSB PSB – |
– – – P |
– – – P |
– – – – |
– – – P |
– – – P |
| 18-5/8 | 87.50 | 473.08 | 130.21 | 11.05 | PS | PSB | PSB | – | – | – | – | – |
| 20 20 20 |
94.00 106.50 133.00 |
508.00 508.00 508.00 |
139.89 158.49 197.93 |
11.13 12.70 16.13 |
PSL – – |
PSLB PSLB PSLB |
PSLB PSLB – |
– – – |
– – – |
– – – |
– – – |
– – – |
| P=Plain end; S=short round thread; L=Long round thread; B–Buttress thread; | ||||||||||||
|
a: Labels are for information and assistance in ordering.
b: Nominal linear masses (col. 4) are shown for information only.
c: The densities of martensitic chromium steels (L80 Types 9Cr and 13Cr) are different from carbon steels. The masses shown are therefore not accurate for martensitic chromium steels. A mass correction factor of 0.989 may be used.
d: Buttress casing i s available with regualr, special clearance coupings or special clearance couplings with special bevel.
|
||||||||||||
API 5CT Chemical Composition and Mechanical Properties
| Group | Grade | Type | C | Mn | Mo | Cr | Ni
max |
Cu
max |
P
max |
S
max |
Si
max |
||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| min | max | min | max | min | max | min | max | ||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
|
1
|
H40
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
–
|
|
J55
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
–
|
|
|
K55
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
–
|
|
|
N80
|
1
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
–
|
|
|
N80
|
Q
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
–
|
|
|
R95
|
–
|
–
|
0.45 c
|
–
|
1.9
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
0.45
|
|
|
2
|
M65
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.03
|
0.03
|
–
|
|
L80
|
1
|
–
|
0.43 a
|
–
|
1.9
|
–
|
–
|
–
|
–
|
0.25
|
0.35
|
0.03
|
0.03
|
0.45
|
|
|
L80
|
9Cr
|
–
|
0.15
|
0.3
|
0.6
|
0.9
|
1.1
|
8
|
10
|
0.5
|
0.25
|
0.02
|
0.01
|
1
|
|
|
L80
|
13Cr
|
0.15
|
0.22
|
0.25
|
1
|
–
|
–
|
12
|
14
|
0.5
|
0.25
|
0.02
|
0.01
|
1
|
|
|
C90
|
1
|
–
|
0.35
|
–
|
1.2
|
0.25 b
|
0.85
|
–
|
1.5
|
0.99
|
–
|
0.02
|
0.01
|
–
|
|
|
T95
|
1
|
–
|
0.35
|
–
|
1.2
|
0.25 d
|
0.85
|
0.4
|
1.5
|
0.99
|
–
|
0.02
|
0.01
|
–
|
|
|
C110
|
–
|
–
|
0.35
|
–
|
1.2
|
0.25
|
1
|
0.4
|
1.5
|
0.99
|
–
|
0.02
|
0.005
|
–
|
|
|
3
|
P110
|
e
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
–
|
0.030 e
|
0.030 e
|
–
|
|
4
|
Q125
|
1
|
–
|
0.35
|
1.35
|
–
|
0.85
|
–
|
1.5
|
0.99
|
–
|
0.02
|
0.01
|
–
|
|
| a The carbon content for L80 may be increased up to 0.50 % maximum if the product is oil-quenched. b The molybdenum content for Grade C90 Type 1 has no minimum tolerance if the wall thickness is less than 17.78 mm. c The carbon content for R95 may be increased up to 0.55 % maximum if the product is oil-quenched. d The molybdenum content for T95 Type 1 may be decreased to 0.15 % minimum if the wall thickness is less than 17.78 mm. e For EW Grade P110, the phosphorus content shall be 0.020 % maximum and the sulfur content 0.010 % maximum. NL = no limit. Elements shown shall be reported in product analysis. |
|||||||||||||||
CASING PIPE MATERIALS – MECHANICAL PROPERTIES
| Group | Grade | Type | Total
elongation under load % |
Yield
strength MPa |
Tensile
strength min. MPa |
Hardness a
max. |
Specified
wall thickness mm |
Allowable
hardness variation b HRC |
||
|---|---|---|---|---|---|---|---|---|---|---|
| min | max | HRC | HBW | |||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
| 1 |
H40
|
–
|
0.5
|
276
|
552
|
414
|
–
|
–
|
–
|
–
|
|
J55
|
–
|
0.5
|
379
|
552
|
517
|
–
|
–
|
–
|
–
|
|
|
K55
|
–
|
0.5
|
379
|
552
|
655
|
–
|
–
|
–
|
–
|
|
|
N80
|
1
|
0.5
|
552
|
758
|
689
|
–
|
–
|
–
|
–
|
|
|
N80
|
Q
|
0.5
|
552
|
758
|
689
|
–
|
–
|
–
|
–
|
|
|
R95
|
–
|
0.5
|
655
|
758
|
724
|
–
|
–
|
–
|
–
|
|
| 2 |
M65
|
–
|
0.5
|
448
|
586
|
586
|
22
|
235
|
–
|
–
|
|
L80
|
1
|
0.5
|
552
|
655
|
655
|
23
|
241
|
–
|
–
|
|
|
L80
|
9Cr
|
0.5
|
552
|
655
|
655
|
23
|
241
|
–
|
–
|
|
|
L80
|
13Cr
|
0.5
|
552
|
655
|
655
|
23
|
241
|
–
|
–
|
|
|
C90
|
1
|
0.5
|
621
|
724
|
689
|
25.4
|
255
|
≤ 12.70
12.71 to 19.04 19.05 to 25.39 ≥ 25.40 |
3.0 4.0 5.0 6.0
|
|
|
T95
|
1
|
0.5
|
655
|
758
|
724
|
25.4
|
255
|
≤ 12.70
12.71 to 19.04 19.05 to 25.39 ≥ 25.40 |
3.0 4.0 5.0 6.0
|
|
|
C110
|
–
|
0.7
|
758
|
828
|
793
|
30
|
286
|
≤ 12.70
12.71 to 19.0 19.05 to 25.39 ≥ 25.40 |
3.0 4.0 5.0 6.0
|
|
| 3 |
P110
|
–
|
0.6
|
758
|
965
|
862
|
–
|
–
|
–
|
–
|
| 4 |
Q125
|
1
|
0.65
|
862
|
1034
|
931
|
b
|
–
|
≤ 12.70
12.71 to 19.04 ≥ 19.05 |
3.0 4.0 5.0
|
| a In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method. b No hardness limits are specified, but the maximum variation is restricted as a manufacturing control in accordance with 7.8 and 7.9 of API Spec. 5CT. |
||||||||||
Manufacturing Processes
Seamless and Welded Tubing
API 5CT casing and tubing can be manufactured using either seamless or welded processes.
Seamless Process
- Billet Preparation: A solid steel billet is heated and pierced to create a hollow shell.
- Hot Rolling: The hollow shell is rolled to reduce its diameter and wall thickness.
- Cold Drawing (Optional): The tube is cold drawn to achieve precise dimensions and surface finish.
- Heat Treatment: The tube undergoes heat treatment to achieve the required mechanical properties.
- Straightening and Cutting: The tube is straightened and cut to the desired length.
Welded Process
- Strip Preparation: Steel strips are slit to the required width.
- Forming: The strips are formed into a cylindrical shape.
- Welding: The edges of the formed strip are welded together.
- Heat Treatment: The welded tube undergoes heat treatment to achieve the required mechanical properties.
- Sizing and Cutting: The tube is sized and cut to the required length.
Heat Treatment
Heat treatment processes such as quenching and tempering are crucial for achieving the desired mechanical properties.
- Quenching and Tempering: Heating the tube to a high temperature, rapidly cooling (quenching), and reheating to a lower temperature (tempering) to achieve the desired strength and toughness.
Testing Requirements
API 5CT specifies rigorous testing requirements to ensure the quality and performance of casing and tubing:
- Tensile Test: Measures tensile strength, yield strength, and elongation.
- Hardness Test: Ensures the material meets specified hardness levels.
- Impact Test: Assesses the material’s toughness at various temperatures.
- Hydrostatic Test: Ensures the tube can withstand internal pressure without leaking.
- Non-Destructive Testing: Includes ultrasonic, magnetic particle, and radiographic testing to detect any defects.
- Sour Service Testing: Ensures resistance to sulfide stress cracking (SSC) for use in sour environments.
Applications
API 5CT casing and tubing are used in various drilling and production environments, including:
- Standard Oil and Gas Wells: Basic grades for conventional wells.
- Deep Oil and Gas Wells: Higher strength grades for deeper wells.
- High-Pressure, High-Temperature (HPHT) Reservoirs: Ultra-high strength grades for extreme conditions.
- Geothermal Wells: Tubing for high-temperature and high-pressure geothermal applications.
- Offshore Drilling: High-strength casing and tubing for deep-water drilling operations.
Advantages and Limitations
Advantages
- Versatility: Wide range of grades to suit different environments.
- Strength: High mechanical properties ensure reliability in demanding applications.
- Durability: Toughness ensures long-term performance in harsh conditions.
- Availability: Available in both seamless and welded forms.
Limitations
- Cost: Higher grades may be more expensive due to alloying elements and heat treatment processes.
- Manufacturing Complexity: Requires precise control over chemical composition and heat treatment.
- Lead Time: Specific grades and sizes may have longer lead times.
Conclusion
API 5CT casing and tubing are essential components in the oil and gas industry, providing structural integrity and transport pathways within the wellbore. Understanding the detailed specifications, grades, and applications of API 5CT casing and tubing helps engineers and designers select the right materials for their projects, ensuring safety and efficiency in challenging drilling and production operations.
By examining the chemical composition, mechanical properties, manufacturing processes, and applications, this analysis provides a comprehensive overview of API 5CT casing and tubing, highlighting their significance in high-performance industrial applications.
A casing pipe is a hollow steel tube that is typically rammed into place through the earth by using a hydraulic or pneumatic jack. After being driven, the displaced soil is removed and the product pipe, or carrier pipe, is inserted inside the steel tube. Available Sizes Category:ERW, HFW or SMLS Standards:API 5CT PSL1/PSL2 J55,K55,N80-1,N80-Q,API 5CT PSL1/PSL2 L80-1, L80-9Cr,L80-13Cr,C90, C95, P110, Q125 Steel Grade:H40, J55, K55, N80
H40 casing steel pipes are essential components in the drilling and production of oil and gas wells. These pipes are manufactured to meet API Spec 5CT standards, ensuring quality, performance, and reliability. Through rigorous manufacturing processes, precise dimensions and tolerances, and comprehensive testing, H40 casing pipes deliver dependable performance in various drilling and production environments.
The American Petroleum Institute specification API 5CT J55 Pipe is designed for use in the oil and gas industry. API 5CT J55 is a commonly used petroleum casing pipe material. It is produced according to the API 5CT standard and used in a variety of well types, both oil and natural gas. The main purposes of using casing or tubing are to protect the wellbore from collapse and to provide a conduit for well fluids. The casing is placed in the well first, followed by tubing, which is often smaller in diameter and thus can be nested inside the casing. Both casing and tubing must be made from strong materials that can withstand the high pressures and temperatures encountered deep underground. API 5CT J55 meets these requirements and is, therefore, an excellent choice for OCTG (oil country tubular goods) applications. It is typically produced as seamless steel pipe, but can also be procured in welded form. API 5CT J55 has a relatively high yield strength and good fatigue resistance, making it an ideal choice for high-pressure, high-load applications such as petroleum products.
API 5CT K55 is a pipe grade specified by the American Petroleum Institute. API 5CT K55 is a type of well casing that is typically used in well drilling operations. The casing and tubing are OCTG (oil country tubular goods) that are used to form the walls of the well. The steel pipe is placed in the well and held in place by cement. The cement helps to protect the well from collapse and keeps the well fluids from escaping. API 5CT K55 is a popular choice for well drilling because it is durable and can withstand high temperatures and pressures.
M65 casing pipe is a crucial component in the drilling and production of oil and gas wells. It is manufactured to meet API 5CT standards, ensuring quality, performance, and reliability. Through rigorous manufacturing processes, precise dimensions and tolerances, and comprehensive testing, M65 casing pipe delivers dependable performance in various drilling and production environments.
L80 casing tubing is a crucial component in the drilling and production of oil and gas wells. It is manufactured to meet API 5CT standards, ensuring quality, performance, and reliability. Through rigorous manufacturing processes, precise dimensions and tolerances, and comprehensive testing, L80 casing tubing delivers dependable performance in various drilling and production environments. Each type (L80-1, L80 13Cr, L80 9Cr) offers specific properties tailored to different operational needs, providing versatility and robustness in challenging conditions.
