API 5CT is a standard specification for casing and tubing used in the oil and gas industry. Casing and tubing are both used to line the walls of a wellbore and provide structural support for the well.
Casing is the pipe that runs from the surface of the well to the bottom, and it serves to protect the wellbore from collapse and prevent fluid migration. It is also used to maintain well control and prevent blowouts.
Tubing, on the other hand, is placed inside the casing and is used to transport oil and gas from the well to the surface. It also serves as a conduit for injecting fluids into the well, such as water or chemicals.
API 5CT specifies the technical delivery conditions for casing and tubing, including material, chemical composition, mechanical properties, dimensions, and thread types. The specification covers several grades of steel, including J55, K55, N80, L80, C90, T95, P110, and Q125.
Casing and tubing are critical components in the oil and gas industry, and they must meet stringent requirements to ensure safe and reliable operations. API 5CT sets these standards, providing a framework for manufacturers and users to ensure that casing and tubing meet the necessary criteria for use in the field.
|
Standard |
API 5CT/ ISO11960 |
|
|
Grade |
Group.1 |
H40/PSL.1, J55/PSL.1, J55/PSL.2, J55/PSL.3, K55/PSL.1, K55/PSL.2, K55/PSL.3, |
|
Group.2 |
M65/PSL.1, M65/PSL.3, L80/PSL.2, L80(1)/PSL.1, L80(1)/PSL.3, L80(9Cr)/PSL.1, |
|
|
Group.3 |
P110/PSL.1, P110/PSL.2, P110/PSL.3, |
|
|
Group.4 |
Q125/PSL.1, Q125/PSL.2, Q125/PSL.3, |
|
|
Minimum Order Quantity |
1 Ton |
|
|
Outside Diameter Ranges |
Tubing |
1.315 inch to 4 1/2 inch or 48.26mm to 114.3mm |
|
Casing |
4 1/2 inch to 13 3/8 inch or 114.3mm to 339.72mm |
|
|
Wall Thickness |
According to API 5CT Standard |
|
|
Length |
Tubing |
R1 (6.10m to 7.32m), R2 (8.53m to 9.75m), R3 (11.58m to 12.80m) |
|
Casing |
R1 (4.88m to 7.62m), R2 (7.62m to 10.36m), R3 (10.36m to 14.63m) |
|
|
Type |
Seamless |
|
|
Type of End-Finish |
Tubing |
P, I, N, U |
|
Casing |
P, S, B, L |
|
Dimensions
| Pipe Casing Sizes, Oilfield Casing Sizes & Casing Drift Sizes | |
| Outer Diameter (Casing Pipe Sizes) | 4 1/2"-20", (114.3-508mm) |
| Standard Casing Sizes | 4 1/2"-20", (114.3-508mm) |
| Thread Type | Buttress thread casing, Long round thread casing, Short round thread casing |
| Function | It can protect the tubing pipe. |
Chemical Composition
| Grade | C≤ | Si≤ | Mn≤ | P≤ | S≤ | Cr≤ | Ni≤ | Cu≤ | Mo≤ | V≤ | Als≤ |
| API 5CT J55 | 0.34-0.39 |
0.20-0.35 |
1.25-1.50 |
0.020 |
0.015 |
0.15 |
0.20 |
0.20 |
/ |
/ |
0.020 |
| API 5CT K55 | 0.34-0.39 |
0.20-0.35 |
1.25-1.50 |
0.020 |
0.015 |
0.15 |
0.20 |
0.20 |
/ |
/ |
0.020 |
| API 5CT N80 | 0.34-0.38 |
0.20-0.35 |
1.45-1.70 |
0.020 |
0.015 |
0.15 |
/ |
/ |
/ |
0.11-0.16 |
0.020 |
| API 5CT L80 | 0.15-0.22 |
1.00 |
0.25-1.00 |
0.020 |
0.010 |
12.0-14.0 |
0.20 |
0.20 |
/ |
/ |
0.020 |
| API 5CT J P110 | 0.26-035 |
0.17-0.37 |
0.40-0.70 |
0.020 |
0.010 |
0.80-1.10 |
0.20 |
0.20 |
0.15-0.25 |
0.08 |
0.020 |
Mechanical Properties
|
Steel Grade |
Yield Strength (Mpa) |
Tensile Strength (Mpa) |
|
API 5CT J55 |
379-552 |
≥517 |
|
API 5CT K55 |
≥655 |
≥517 |
|
API 5CT N80 |
552-758 |
≥689 |
|
API 5CT L80 |
552-655 |
≥655 |
|
API 5CT P110 |
758-965 |
≥862 |
