- Keywords: API casing, API tubing, N80 casing, N80 tubing, oil casing, oil tubing, casing tubing
- Standard and Grades: API 5CT J55 / K55, N80-1, N80Q, C90, T95, P110, Q125 and 13Cr
- Casing Pipe Size range: 5 1/2” to 20” Length usually in R3.
- Tubing Pipe dimensions range: 1.0”, 1.315”, 1.66”, 1.9”, 2.063”, 2 3/8”, 3 1/2”and 4 1 /2”, Length in R2.
- Type of connections for Casing: BTC (thread coupling buttress), LTC (long round thread coupling), premium connection.
- Types of connections for Tubing: BTC, NUE, EUE, Premium
Product Description of Casing and Tubing
Casing and tubing are the important parts of OCTG products. It is widely used for the drilling wells and transporting the fluid in the energy project.
For the tubing, it is a pipe used for the transportation of crude oil and natural gas from an oil or gas layer to the surface after drilling is complete. Tubing is the conduit through which oil and gas are brought from the producing formations to the field surface facilities for processing. Tubing must be adequately strong to resist loads and deformations associated with production and workovers.
For the casing, it is a series of steel pipes that are run into a drilled oil well to stabilize the well, keep contaminants and water out of the oil stream, and prevent oil from leaching into the groundwater. Casing is installed in layers, in sections of decreasing diameter that are joined together to form casing strings.
What are the differences between casing and tubing?
Tubing are pipes through which the oil or gas is transported from the wellbore. Tubing segments are generally around 30 ft (9 m) long with a threaded connection on each end. Tubing comply with Specifications on Casing and Tubing (API Spec 5CT), Specifications on Processing, Measuring and Inspecting Casing, Tubing and Threads (API Spec 5B) and other related standards.
Casing is a special tubular product for oil (gas or water) extraction. Casing is particularly exposed to axial tension and internal pressure by the pumped oil or gas emulsion. Casing comply with Specifications on Casing and Tubing (API Spec 5CT), Specifications on Processing, Measuring and Inspecting Casing, Tubing and Threads (API Spec 5B) and other related standards.
Standard of Casing and Tubing
Chemical compositions of casing and tubing
Standard | Grade | Chemical compositions（％） | |||||||||
API SPEC 5CT | J55 | C | Si | Mn | P | S | Cr | Ni | Cu | Mo | V |
K55 | 0.34～0.39 | 0.20～0.35 | 1.25～1.50 | ≤0.020 | ≤0.015 | ≤0.15 | ≤0.20 | ≤0.20 | / | / | |
N80 | 0.34～0.38 | 0.20～0.35 | 1.45～1.70 | ≤0.020 | ≤0.015 | ≤0.15 | / | / | / | 0.11～0.16 | |
L80 | 0.15～0.22 | ≤1.00 | 0.25～1.00 | ≤0.020 | ≤0.010 | 12.0～14.0 | ≤0.20 | ≤0.20 | / | / | |
P110 | 0.26～0.395 | 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 | |
Mechanical properties of casing and tubing
Grade | Type | Total elongation | Yield strength | Yield strength | Tensile strength | Hardness | Hardness |
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 | - | - |
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 | - | 0.5 | 621 | 724 | 689 | 25.4 | 255 |
C95 | - | 0.5 | 655 | 758 | 724 | - | - |
T95 | - | 0.5 | 655 | 758 | 724 | 25.4 | 255 |
P110 | - | 0.6 | 758 | 965 | 862 | - | - |
Q125 | All | 0.65 | 862 | 1034 | 931 | - | - |
Specification of Casing and Tubing
Tubing Size | Nominal Weight lb/ft | Outside Diameter | Wall Thickness | Type of End Finish | ||||||||
Grade | ||||||||||||
Non -upset | External -upset | in | mm | in | mm | J55 | L80-1 | N80 | C90 | T95 | P110 | |
1.900" | 2.40 | - | 1.900 | 48.26 | 0.125 | 3.18 | PI | - | - | - | - | - |
2.75 | 2.90 | 1.900 | 48.26 | 0.145 | 3.68 | PNUI | PNUI | PNUI | PNUI | PNUI | - | |
3.65 | - | 1.900 | 48.26 | 0.200 | 5.08 | PU | PU | PU | PU | PU | PU | |
2 3/8" | 4.00 | - | 2.375 | 60.32 | 0.167 | 4.24 | PN | PN | PN | PN | PN | - |
4.00 | 4.70 | 2.375 | 60.32 | 0.190 | 4.83 | PNU | PNU | PNU | PNU | PNU | - | |
5.80 | 5.95 | 2.375 | 60.32 | 0.254 | 6.45 | - | PNU | PNU | PNU | PNU | PNU | |
6.60 | - | 2.375 | 60.32 | 0.259 | 7.49 | - | - | P | P | P | PNU | |
7.35 | 7.45 | 2.375 | 60.32 | 0.336 | 8.53 | - | PU | - | PU | PU | - | |
2 7/8" | 6.40 | 6.50 | 2.875 | 73.02 | 0.217 | 5.51 | PNU | PNU | PNU | PNU | PNU | - |
7.80 | 7.90 | 2.875 | 73.02 | 0.276 | 7.01 | - | PNU | PNU | PNU | PNU | PNU | |
8.60 | 8.70 | 2.875 | 73.02 | 0.308 | 7.82 | - | PNU | PNU | PNU | PNU | PNU | |
9.35 | 9.45 | 2.875 | 73.02 | 0.340 | 8.64 | - | PU | - | PU | PU | PNU | |
10.50 | - | 2.875 | 73.02 | 0.392 | 9.96 | - | P | - | P | P | - | |
11.50 | - | 2.875 | 73.02 | 0.440 | 11.18 | - | P | - | P | P | - | |
3 1/2" | 7.70 | - | 3.500 | 88.90 | 0.216 | 5.49 | PN | PN | PN | PN | PN | - |
9.20 | 9.30 | 3.500 | 88.90 | 0.254 | 6.54 | PNU | PNU | PNU | PNU | PNU | - | |
10.20 | - | 3.500 | 88.90 | 0.289 | 7.34 | PN | PN | PN | PN | PN | PNU | |
12.70 | 12.95 | 3.500 | 88.90 | 0.375 | 9.52 | - | PNU | PNU | PNU | PNU | - | |
14.30 | - | 3.500 | 88.90 | 0.430 | 10.92 | - | P | - | P | P | PNU | |
15.50 | - | 3.500 | 88.90 | 0.476 | 12.00 | - | P | - | P | P | - | |
17.00 | - | 3.500 | 88.90 | 0.530 | 13.46 | - | P | - | P | P | - | |
4" | 9.50 | - | 4.000 | 101.60 | 0.226 | 5.74 | PN | PN | PN | PN | PN | - |
10.70 | - | 4.000 | 101.60 | 0.262 | 6.65 | PU | PU | PU | PU | PU | - | |
4 1/2" | 12.60 | 12.75 | 4.500 | 114.30 | 0.271 | 6.88 | PNU | PNU | PNU | PNU | PNU | - |
15.20 | - | 4.500 | 114.30 | 0.380 | 8.56 | - | P | - | P | P | - | |
17.00 | - | 4.500 | 114.30 | 0.380 | 9.65 | - | P | - | P | P | - | |
18.90 | - | 4.500 | 114.30 | 0.430 | 10.92 | - | P | - | P | P | - | |
21.50 | - | 4.500 | 114.30 | 0.500 | 12.70 | - | P | - | P | P | - | |
23.70 | - | 4.500 | 114.30 | 0.560 | 14.22 | - | P | - | P | P | - | |
26.10 | - | 4.500 | 114.30 | 0.630 | 16.00 | - | P | - | P | P | - | |
Casing Size | NominalWeight lb/ft | Outside Diameter | Wall Thickness | Type of End Finish | |||||||||
Grade | |||||||||||||
in | mm | in | mm | J55 K55 | L80-1 | N80 | C90 | C95 | T95 | P110 | M65 | ||
4 1/2" | 9.50 | 4.500 | 114.30 | 0.205 | 5.21 | PS | - | - | - | - | - | - | - |
10.50 | 4.500 | 114.30 | 0.224 | 5.69 | PSB | - | - | - | - | - | - | - | |
11.60 | 4.500 | 114.30 | 0.250 | 6.35 | PSLB | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
13.50 | 4.500 | 114.30 | 0.290 | 7.37 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
15.10 | 4.500 | 114.30 | 0.337 | 8.56 | - | - | - | - | - | - | PLB | - | |
5" | 11.50 | 5.000 | 127.00 | 0.220 | 5.59 | PS | - | - | - | - | - | - | - |
13.00 | 5.000 | 127.00 | 0.253 | 7.52 | PSLB | - | - | - | - | - | - | - | |
15.00 | 5.000 | 127.00 | 0.296 | 9.19 | PSLB | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
18.00 | 5.000 | 127.00 | 0.362 | 9.19 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
21.40 | 5.000 | 127.00 | 0.437 | 11.10 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
23.20 | 5.000 | 127.00 | 0.478 | 12.14 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
24.10 | 5.000 | 127.00 | 0.500 | 12.70 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
5 1/2" | 14.00 | 5.500 | 139.70 | 0.244 | 6.20 | PS | - | - | - | - | - | - | - |
15.50 | 5.500 | 139.70 | 0.275 | 6.98 | PSLB | - | - | - | - | - | - | - | |
17.00 | 5.500 | 139.70 | 0.304 | 7.72 | PSLB | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
20.00 | 5.500 | 139.70 | 0.361 | 9.17 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
23.00 | 5.500 | 139.70 | 0.415 | 10.54 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
26.80 | 5.500 | 139.70 | 0.500 | 12.70 | - | - | - | P | - | P | P | P | |
29.70 | 5.500 | 139.70 | 0.562 | 14.27 | - | - | - | P | - | P | P | P | |
32.60 | 5.500 | 139.70 | 0.625 | 15.88 | - | - | - | P | - | P | P | P | |
35.30 | 5.500 | 139.70 | 0.687 | 17.45 | - | - | - | P | - | P | P | P | |
38.00 | 5.500 | 139.70 | 0.750 | 19.05 | - | - | - | P | - | P | P | P | |
40.50 | 5.500 | 139.70 | 0.812 | 20.62 | - | - | - | P | - | P | P | P | |
43.10 | 5.500 | 139.70 | 0.875 | 22.22 | - | - | - | P | - | P | P | P | |
7" | 20.00 | 7.000 | 177.80 | 0.272 | 6.91 | PS | - | - | - | - | - | - | PS |
23.00 | 7.000 | 177.80 | 0.317 | 8.05 | PSLB | PLB | PLB | PLB | PLB | - | - | PLB | |
26.00 | 7.000 | 177.80 | 0.362 | 9.19 | PSLB | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
29.00 | 7.000 | 177.80 | 0.408 | 10.36 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
32.00 | 7.000 | 177.80 | 0.453 | 11.51 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
35.00 | 7.000 | 177.80 | 0.498 | 12.65 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
38.00 | 7.000 | 177.80 | 0.540 | 13.72 | - | PLB | PLB | PLB | PLB | PLB | PLB | PLB | |
9 5/8" | 32.30 | 9.625 | 244.48 | 0.312 | 7.92 | - | - | - | - | - | - | - | - |
36.00 | 9.625 | 244.48 | 0.352 | 8.94 | PSLB | - | - | - | - | - | - | PSLB | |
40.00 | 9.625 | 244.48 | 0.395 | 8.94 | PSLB | PLB | PLB | PLB | PLB | PLB | - | PSLB | |
43.50 | 9.625 | 244.48 | 0.435 | 11.05 | - | PLB | PLB | PLB | PLB | PLB | PLB | - | |
47.00 | 9.625 | 244.48 | 0.472 | 11.99 | - | PLB | PLB | PLB | PLB | PLB | PLB | - | |
53.50 | 9.625 | 244.48 | 0.545 | 13.84 | - | PLB | PLB | PLB | PLB | PLB | PLB | - | |
58.40 | 9.625 | 244.48 | 0.595 | 15.11 | - | PLB | PLB | PLB | PLB | PLB | PLB | - | |
59.40 | 9.625 | 244.48 | 0.609 | 15.47 | - | - | - | P | - | P | - | - | |
64.90 | 9.625 | 244.48 | 0.672 | 17.07 | - | - | - | P | - | P | - | - | |
70.30 | 9.625 | 244.48 | 0.734 | 18.64 | - | - | - | P | - | P | - | - | |
75.60 | 9.625 | 244.48 | 0.797 | 20.24 | - | - | - | P | - | P | - | - | |
13 3/8" | 48.00 | 13.375 | 339.72 | 0.330 | 8.38 | - | - | - | - | - | - | - | - |
54.50 | 13.375 | 339.72 | 0.380 | 9.65 | PSB | - | - | - | - | - | - | PSB | |
61.00 | 13.375 | 339.72 | 0.430 | 10.92 | PSB | - | - | - | - | - | - | PSB | |
68.00 | 13.375 | 339.72 | 0.480 | 12.19 | PSB | PSB | PSB | PSB | PSB | PSB | PSB | PSB | |
72.00 | 13.375 | 339.72 | 0.514 | 13.06 | - | PSB | PSB | PSB | PSB | PSB | PSB | ||
Application of Casing and Tubing
1. Reinforce the well wall to prevent formation collapse.
2. Isolate different oil layers and water layers to realize layered mining.
3. Tubing and Casing are convenient to implement measures such as fracturing and acidification and maintenance operations.
4. Form an oil flow channel to cooperate with the oil pipe to achieve the purpose of oil recovery.
