OCTG
OCTG (Casing and Tubing)
OCTG (Oil Country Tubular Goods) refers to a group of rolled metal products used in the oil and gas industry, including casing and tubing. They are indeed used in the drilling process.
Casing is a term that refers to the OCTG that is installed inside a drilled well to protect and support the well stream. The Casing completely surrounds the wellbore, protecting the soil layers and, most importantly, the groundwater from contamination by drilling mud and frac fluids. Additionally, it stabilizes the wellbore, which means that the casing must be able to withstand extremely high loads.
PRODUCT FEATURES
Types of OCTG (Tubing and Casing)
- Lining with Casing
In this type of OCTG, casing refers to the external tubes. Casing completely surrounds the wellbore, protecting the soil layers and, most importantly, the groundwater from contamination by drilling mud and/or frac fluids. Additionally, it stabilizes the wellbore, which means that the casing must be able to withstand extremely high loads. Drilling and casing operations alternate – the drill string is removed at predetermined intervals and the wellbore is lined and cemented with casing. Then the drilling resumes.
- Production with Tubing
In this type of OCTG, tubing is used to carry petroleum from the well’s depths to the surface – this is the third phase of the wellbore. Oil and gas occasionally self-elevate to the surface; however, pumps are typically required to bring the fluids to the surface. Besides the 4 1/2-inch diameter, tubing is normally smaller in diameter than the casing. A casing or tubing with an outer diameter of 114.3 mm (4 1/2 inches) is considered a threshold size. Anything smaller than tubing is referred to as tubing, while anything larger is referred to as casing. The casing shrinks in diameter as it descends from the surface to the bottom of the well – there are various types of casing depending on their purpose and diameter. The “kickoff point” is the gradual transition of the wellbore from vertical to horizontal. Horizontal drilling enables more precise targeting of deposits. After the procedure, the drill string is removed and the production casing is inserted and cemented into the wellbore. After fracturing the well, the tubing is installed inside the production casing.
Production Standards of OCTG
APT 5CT specified that casing and tubing used in OCTG production must be cased with a material that is both strong and functional. The standard establishes requirements for three Product Specification Levels and a variety of grades (API 5CT J55, K55, N80, L80, P110).
Dimensions and Sizes of OCTG (Tubing and Casing)
- Specification & Size of Tubing
DN | O. D. | Weight | W. T. | End Processing | |||||||||
Non-upset coupling-thread | Upset coupling-thread | OCTG Steel Grade | |||||||||||
in | mm | lb./ft. | lb./ft. | in | mm | H40 | J55 | L80 | N80 | C90 | T95 | P110 | |
2-3/8 | 2.375 | 60.32 | 4.00 | – | 0.167 | 4.24 | PU | PN | PN | PN | PN | PN | – |
4.60 | 4.70 | 0.190 | 4.83 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | |||
5.80 | 5.95 | 0.254 | 6.45 | – | – | PNU | PNU | PNU | PNU | PNU | |||
6.60 | – | 0.295 | 7.49 | – | – | P | – | P | P | – | |||
7.35 | 7.45 | 0.336 | 8.53 | – | – | PU | – | PU | PU | – | |||
2-7/8 | 2.875 | 73.02 | 6.40 | 6.50 | 0.217 | 5.51 | PNU | PNU | – | – | – | – | – |
7.80 | 7.90 | 0.276 | 7.01 | – | – | – | – | – | – | – | |||
8.60 | 8.70 | 0.308 | 7.82 | – | – | PLB | PLB | PLBE | – | PLB | |||
9.35 | 9.45 | 0.340 | 8.64 | – | – | PLB | PLB | PLBE | – | PLB | |||
10.50 | – | 0.392 | 9.96 | – | – | PLB | PLB | PLB | – | PLB | |||
11.50 | – | 0.440 | 11.18 | – | – | – | – | PLB | – | ||||
3-1/2 | 3.500 | 88.90 | 7.70 | – | 0.216 | 5.49 | PN | PN | PN | PN | PN | PN | – |
9.20 | 9.30 | 0.254 | 6.45 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | |||
10.20 | – | 0.289 | 7.34 | PN | PN | PN | PN | PN | PN | – | |||
12.70 | 12.95 | 0.375 | 9.52 | – | – | PNU | PNU | PNU | PNU | PNU | |||
14.30 | – | 0.430 | 10.92 | – | – | P | – | P | P | – | |||
15.50 | – | 0.476 | 12.09 | – | – | P | – | P | P | – | |||
17.00 | – | 0.530 | 13.46 | – | – | P | – | P | P | – | |||
4 | 4.000 | 101.60 | 9.50 | – | 0.226 | 5.74 | PN | PN | PN | PN | PN | PN | – |
– | 11.00 | 0.262 | 6.65 | PU | PU | PU | PU | PU | PU | – | |||
13.20 | – | 0.330 | 8.38 | – | – | P | – | P | P | – | |||
16.10 | – | 0.415 | 10.54 | – | – | P | – | P | P | – | |||
18.90 | – | 0.500 | 12.70 | – | – | P | – | P | P | – | |||
22.20 | – | 0.610 | 15.49 | – | – | P | – | P | P | – | |||
4-1/2 | 4.500 | 114.30 | 12.60 | 12.75 | 0.271 | 6.88 | PNU | PNU | PNU | PNU | PNU | PNU | – |
15.20 | – | 0.337 | 8.56 | – | – | P | – | P | P | – | |||
17.00 | – | 0.380 | 9.65 | – | – | P | – | P | P | – | |||
18.90 | – | 0.430 | 10.92 | – | – | P | – | P | P | PLB | |||
21.50 | – | 0.500 | 12.70 | – | – | P | – | P | P | PLB | |||
23.70 | – | 0.560 | 14.22 | – | – | P | – | P | P | PLB | |||
26.10 | – | 0.630 | 16.00 | – | – | P | – | P | P | PLB | |||
P——Plain；N—— Non-upset coupling-thread；U—— Upset coupling-thread； L——Integral | |||||||||||||
- Specification & Size of Casing Pipe
DN | O. D. | Weight | W. T. | End Machining Form | ||||||||
OCTG Steel Grade | ||||||||||||
in | mm | lb/ft | kg/m | in | mm | H40 | J55 | L80 | N80 | C90 | P110 | |
K55 | T95 | |||||||||||
4-1/2 | 4.500 | 114.3 | 9.50 | 14.14 | 0.205 | 5.21 | PS | PS | – | – | – | – |
10.50 | 15.63 | 0.224 | 5.69 | – | PSB | – | – | – | – | |||
11.60 | 17.26 | 0.250 | 6.35 | – | PSLB | PLB | PLB | PLB | PLB | |||
13.50 | 20.09 | 0.290 | 7.37 | – | – | PLB | PLB | PLB | PLB | |||
15.10 | 22.47 | 0.337 | 9.56 | – | – | – | – | – | PLB | |||
5 | 5.000 | 127 | 11.50 | 17.11 | 0.220 | 5.59 | – | PS | – | – | – | – |
13.00 | 19.35 | 0.253 | 6.43 | – | PSLB | – | – | – | – | |||
15.00 | 22.32 | 0.296 | 7.52 | – | PSLB | PLB | PLB | PLBE | PLB | |||
18.00 | 26.79 | 0.362 | 9.19 | – | – | PLB | PLB | PLBE | PLB | |||
21.40 | 31.85 | 0.437 | 11.10 | – | – | PLB | PLB | PLB | PLB | |||
23.20 | 34.53 | 0.478 | 12.14 | – | – | – | – | PLB | – | |||
24.10 | 35.86 | 0.500 | 12.70 | – | – | – | – | PLB | – | |||
5-1/2 | 5.500 | 139.7 | 14.00 | 20.83 | 0.244 | 6.20 | PS | PS | – | – | – | – |
15.50 | 23.07 | 0.275 | 6.98 | – | PSLB | – | – | – | – | |||
17.00 | 25.30 | 0.304 | 7.72 | – | PSLB | PLB | PLB | PLBE | PLB | |||
20.00 | 29.76 | 0.361 | 9.17 | – | – | PLB | PLB | PLBE | PLB | |||
23.00 | 34.23 | 0.415 | 10.54 | – | – | PLB | PLB | PLBE | PLB | |||
26.80 | 39.88 | 0.500 | 12.70 | – | – | – | – | – | – | |||
29.70 | 44.20 | 0.562 | 14.27 | – | – | – | – | – | – | |||
32.60 | 48.51 | 0.625 | 15.88 | – | – | – | – | – | – | |||
35.30 | 52.53 | 0.687 | 17.45 | – | – | – | – | – | – | |||
38.00 | 56.55 | 0.750 | 19.05 | – | – | – | – | – | – | |||
40.50 | 60.27 | 0.812 | 20.62 | – | – | – | – | – | – | |||
43.10 | 64.14 | 0.875 | 22.22 | – | – | – | – | – | – | |||
6-5/8 | 6.625 | 168.28 | 20.00 | 29.76 | 0.288 | 7.32 | PS | PSLB | – | – | – | – |
24.00 | 35.72 | 0.352 | 8.94 | – | PSLB | PLB | PLB | PLBE | PLB | |||
28.00 | 41.67 | 0.417 | 10.59 | – | – | PLB | PLB | PLBE | PLB | |||
32.00 | 47.62 | 0.475 | 12.06 | – | – | PLB | PLB | PLBE | PLB | |||
7 | 7.000 | 177.8 | 17.00 | 25.30 | 0.231 | 5.87 | PS | – | – | – | – | – |
20.00 | 29.76 | 0.272 | 6.91 | PS | PS | – | – | – | – | |||
23.00 | 34.23 | 0.317 | 8.05 | – | PSLB | PLB | PLB | PLBE | – | |||
26.00 | 38.69 | 0.362 | 9.19 | – | PSLB | PLB | PLB | PLBE | PLB | |||
29.00 | 43.16 | 0.408 | 10.36 | – | – | PLB | PLB | PLBE | PLB | |||
32.00 | 47.62 | 0.453 | 11.51 | – | – | PLB | PLB | PLBE | PLB | |||
35.00 | 52.09 | 0.498 | 12.65 | – | – | PLB | PLB | PLBE | PLB | |||
38.00 | 56.55 | 0.540 | 13.72 | – | – | PLB | PLB | PLBE | PLB | |||
42.70 | 63.54 | 0.625 | 15.88 | – | – | – | – | – | – | |||
46.40 | 69.05 | 0.687 | 17.45 | – | – | – | – | – | – | |||
50.10 | 74.56 | 0.750 | 19.05 | – | – | – | – | – | – | |||
53.60 | 79.77 | 0.812 | 20.62 | – | – | – | – | – | – | |||
57.10 | 84.97 | 0.875 | 22.22 | – | – | – | – | – | – | |||
7-5/8 | 7.625 | 193.68 | 24.00 | 35.72 | 0.300 | 7.62 | PS | – | – | – | – | – |
26.40 | 39.29 | 0.328 | 8.33 | – | PSLB | PLB | PLB | PLBE | PLB | |||
29.70 | 44.20 | 0.375 | 9.52 | – | – | PLB | PLB | PLBE | PLB | |||
33.70 | 50.15 | 0.430 | 10.92 | – | – | PLB | PLB | PLBE | PLB | |||
39.00 | 58.05 | 0.500 | 12.70 | – | – | PLB | PLB | PLBE | PLB | |||
42.80 | 63.69 | 0.562 | 14.27 | – | – | PLB | PLB | PLB | PLB | |||
45.30 | 67.41 | 0.595 | 15.11 | – | – | PLB | PLB | PLB | PLB | |||
47.10 | 70.09 | 0.625 | 15.88 | – | – | PLB | PLB | PLB | PLB | |||
51.20 | 76.19 | 0.687 | 17.45 | – | – | – | – | – | – | |||
55.30 | 80.30 | 0.750 | 19.05 | – | – | – | – | – | – | |||
8-5/8 | 8.625 | 219.08 | 24.00 | 35.72 | 0.264 | 6.71 | – | PS | – | – | – | – |
28.00 | 41.62 | 0.304 | 7.72 | PS | – | – | – | – | – | |||
32.00 | 47.62 | 0.352 | 8.94 | PS | PSLB | – | – | – | – | |||
36.00 | 53.57 | 0.400 | 10.16 | – | PSLB | PLB | PLB | PLBE | PLB | |||
40.00 | 59.53 | 0.450 | 11.43 | – | – | PLB | PLB | PLBE | PLB | |||
44.00 | 65.48 | 0.500 | 12.70 | – | – | PLB | PLB | PLBE | PLB | |||
49.00 | 72.92 | 0.557 | 14.15 | – | – | PLB | PLB | PLBE | PLB | |||
9-5/8 | 9.625 | 244.48 | 32.30 | 48.07 | 0.312 | 7.92 | PS | – | – | – | – | – |
36.00 | 53.57 | 0.352 | 8.94 | PS | PSLB | – | – | – | – | |||
40.00 | 59.53 | 0.395 | 10.03 | – | PSLB | PLB | PLB | PLBE | – | |||
43.50 | 64.73 | 0.435 | 11.05 | – | – | PLB | PLB | PLBE | PLB | |||
47.00 | 69.94 | 0.472 | 11.99 | – | – | PLB | PLB | PLBE | PLB | |||
53.50 | 79.62 | 0.545 | 13.84 | – | – | PLB | PLB | PLBE | PLB | |||
58.40 | 86.91 | 0.595 | 15.11 | – | – | PLB | PLB | PLB | PLB | |||
59.40 | 88.40 | 0.609 | 15.47 | – | – | – | – | – | – | |||
64.90 | 96.58 | 0.672 | 17.07 | – | – | – | – | – | – | |||
70.30 | 104.62 | 0.734 | 18.64 | – | – | – | – | – | – | |||
75.60 | 112.50 | 0.797 | 20.24 | – | – | – | – | – | – | |||
10-3/4 | 10.750 | 273.05 | 32.75 | 48.74 | 0.279 | 7.09 | PS | – | – | – | – | – |
40.50 | 60.27 | 0.350 | 8.89 | PS | PSB | – | – | – | – | |||
15.50 | 67.71 | 0.400 | 10.16 | – | PSB | – | – | – | – | |||
51.00 | 75.90 | 0.450 | 11.43 | – | PSB | PSB | PSB | PSBE | PSB | |||
55.50 | 82.59 | 0.495 | 12.57 | – | – | PSB | PSB | PSBE | PSB | |||
60.70 | 90.33 | 0.545 | 13.84 | – | – | – | – | PSBE | PSB | |||
65.70 | 97.77 | 0.595 | 15.11 | – | – | – | – | PSB | PSB | |||
73.20 | 108.93 | 0.672 | 17.07 | – | – | – | – | – | – | |||
79.20 | 117.86 | 0.734 | 18.64 | – | – | – | – | – | – | |||
85.30 | 126.94 | 0.797 | 20.24 | – | – | – | – | – | – | |||
11-3/4 | 11.750 | 42.00 | 62.50 | 0.333 | 8.46 | PS | – | – | – | – | – | |
47.00 | 69.94 | 0.375 | 20.24 | – | – | – | – | – | – | |||
54.00 | 80.36 | 0.435 | 8.46 | – | – | – | – | – | – | |||
60.00 | 89.29 | 0.489 | 9.53 | – | – | – | – | – | – | |||
65.00 | 96.73 | 0.534 | 11.05 | – | – | – | – | – | – | |||
71.00 | 105.66 | 0.582 | 14.42 | – | – | – | – | – | – | |||
13-3/8 | 13.375 | 339.73 | 48.00 | 71.43 | 0.330 | 8.38 | PS | – | – | – | – | – |
54.50 | 81.10 | 0.380 | 9.65 | – | PSB | – | – | – | – | |||
61.00 | 90.78 | 0.430 | 10.92 | – | PSB | – | – | – | – | |||
68.00 | 101.19 | 0.480 | 12.19 | – | PSB | PSB | PSB | PSB | PSB | |||
72.00 | 107.15 | 0.514 | 13.06 | – | – | PSB | PSB | PSB | PSB | |||
16 | 16.000 | 406.4 | 65.00 | 96.73 | 0.375 | 9.53 | PS | – | – | – | – | – |
75.00 | 111.61 | 0.438 | 11.13 | – | PSB | – | – | – | – | |||
84.00 | 125.01 | 0.495 | 12.57 | – | PSB | – | – | – | – | |||
109.00 | 162.21 | 0.656 | 16.66 | – | P | P | P | – | P | |||
18-5/8 | 18.625 | 473.08 | 87.50 | 130.21 | 0.435 | 11.05 | PS | PSB | – | – | – | – |
20 | 20.000 | 508 | 94.00 | 139.89 | 0.438 | 11.13 | PSL | PSLB | – | – | – | – |
106.50 | 158.49 | 0.500 | 12.70 | – | PSLB | – | – | – | – | |||
133.00 | 197.93 | 0.635 | 16.13 | – | PSLB | – | – | – | – | |||
P——Plain；S——Short-thread；L——Long-thread；B——Buttress thread；E——Extreme thread | ||||||||||||
Chemical Composition of OCTG (Tubing and Casing)
Group | OCTG Steel Grade | Type | C | Mn | Mo | Cr | Ni | Cu | P | S | Si | ||||
min. | max. | min. | max. | min. | max. | min. | max. | min. | max. | max. | max. | max. | |||
1 | H40 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – |
J55 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – | |
K55 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – | |
N80 | 1 | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – | |
Q | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – | ||
2 | M65 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – |
L80 | 1 | – | 0.43 | – | 1.9 | – | – | – | – | 0.25 | 0.35 | 0.03 | 0.03 | 0.5 | |
9Cr | – | 0.15 | 0.3 | 0.6 | 0.9 | 1.1 | 8 | 10 | 0.5 | 0.25 | 0.02 | 0.01 | 1.0 | ||
13Cr | 0.15 | 0.22 | 0.25 | 1 | – | – | 12 | 14 | 0.5 | 0.25 | 0.02 | 0.01 | 1.0 | ||
C90 | 1 | – | 0.35 | – | 1.2 | 0.25 | 0.85 | – | 1.5 | 0.99 | – | 0.02 | 0.01 | – | |
2 | – | 0.5 | – | 1.9 | – | NL | – | NL | 0.99 | – | 0.03 | 0.01 | – | ||
C95 | – | – | 0.45 | – | 1.9 | – | – | – | – | – | – | 0.03 | 0.03 | 0.5 | |
T95 | 1 | – | 0.35 | – | 1.2 | 0.25 | 0.85 | 0.4 | 1.5 | 0.99 | – | 0.02 | 0.01 | – | |
2 | – | 0.5 | – | 1.9 | – | – | – | – | 0.99 | – | 0.03 | 0.01 | – | ||
3 | P110 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.03 | – |
4 | Q125 | 1 | – | 0.35 | – | 1.35 | – | 0.85 | – | 1.5 | 0.99 | – | 0.02 | 0.01 | – |
2 | – | 0.35 | – | 1 | – | NL | – | NL | 0.99 | – | 0.02 | 0.02 | – | ||
3 | – | 0.5 | – | 1.9 | – | NL | – | NL | 0.99 | – | 0.03 | 0.01 | – | ||
4 | – | 0.5 | – | 1.9 | – | NL | – | NL | 0.99 | – | 0.03 | 0.02 | – | ||
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 WT 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 WT 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. | |||||||||||||||
Mechanical Properties of OCTG (Tubing and Casing)
Group | OCTG Steel Grade | Type | Total | Yield Strength | Tensile | Hardness | W. T. | Changes in Hardness | ||
min. | max. | min. | HRC | HBW | ||||||
1 | H40 | – | 0.5 | 276 | 552 | 414 | – | – | – | – |
J55 | – | 379 | 552 | 517 | – | – | – | – | ||
K55 | – | 379 | 552 | 655 | – | – | – | – | ||
N80 | 1 | 552 | 758 | 689 | – | – | – | – | ||
Q | 552 | 758 | 689 | – | – | – | – | |||
2 | M65 | – | 0.5 | 448 | 586 | 586 | 22 | 235 | – | – |
L80 | 1 | 552 | 655 | 655 | 23 | 241 | – | – | ||
9Cr | 552 | 655 | 655 | 23 | 241 | – | – | |||
13Cr | 552 | 655 | 655 | 23 | 241 | – | – | |||
C90 | 1、2 | 621 | 724 | 689 | 25.4 | 255 | ≤ 12.70 | 3.0 | ||
621 | 724 | 689 | 25.4 | 255 | 12.71 ~ 19.04 | 4.0 | ||||
621 | 724 | 689 | 25.4 | 255 | 19.05 ~ 25.39 | 5.0 | ||||
621 | 724 | 689 | 25.4 | 255 | ≥25.40 | 6.0 | ||||
C95 | – | 655 | 758 | 724 | – | – | – | – | ||
T95 | 1、2 | 655 | 758 | 724 | 25.4 | 255 | ≤ 12.70 | 3.0 | ||
655 | 758 | 724 | 25.4 | 255 | 12.71 ~ 19.04 | 4.0 | ||||
655 | 758 | 724 | 25.4 | 255 | 19.05 ~ 25.39 | 5.0 | ||||
655 | 758 | 724 | 25.4 | 255 | ≥25.40 | 6.0 | ||||
3 | P110 | – | 0.6 | 758 | 965 | 862 | – | – | – | – |
4 | Q125 | all | 0.65 | 862 | 1034 | 931 | – | – | ≤ 12.70 | 3.0 |
862 | 1034 | 931 | – | – | 12.71 ~ 19.04 | 4.0 | ||||
862 | 1034 | 931 | – | – | ≥19.05 | 5.0 | ||||
