Key Differences Between  API 5ct K55 and J55 Oil well Casing Pipe
API 5CT K55 and J55 are two common grades of Oil Well Casing pipe used in the Petroleum Industry. While they may seem similar at first glance, there are key differences between the two that are important to understand when selecting the right casing pipe for a particular application. One of the main differences between API 5CT K55 and J55 is their yield strength. K55 has a minimum yield strength of 55,000 psi, while J55 has a minimum yield strength of 55,000 psi. This means that K55 is slightly stronger than J55, which can be an important factor in certain drilling environments where higher strength is required to withstand the pressures and stresses of drilling operations. Another important difference between K55 and J55 is their chemical composition. K55 has a higher carbon content than J55, which can affect its mechanical properties and performance in the field. The higher carbon content in K55 can make it more susceptible to cracking and corrosion, especially in harsh drilling conditions. On the other hand, J55 has a lower carbon content, which can make it more resistant to corrosion and cracking.Labels | Outside Diameter (d/mm) | T&C (kg/m) | Wall thickness (t/mm) | Type of end-finish | |||||||
1 | 2 | J55/K55 | M65 | l80/R95 | N80-1/Q | C90/T95 | P110 | Q125 | |||
4-1/2 | 9.50 | 114.30 | 14.14 | 5.21 | PS | PS | – | – | – | – | – |
10.50 | 114.30 | 15.63 | 5.69 | PSB | PSB | – | – | – | – | – | |
11.60 | 114.30 | 17.26 | 6.35 | PSLB | PLB | PLB | PLB | PLB | PLB | – | |
13.50 | 114.30 | 20.09 | 7.37 | – | PLB | PLB | PLB | PLB | PLB | – | |
15.10 | 114.30 | 22.47 | 8.56 | – | – | – | – | – | PLB | PLB | |
5 | 11.50 | 127.00 | 17.11 | 5.59 | PS | PS | – | – | – | – | – |
13.00 | 127.00 | 19.35 | 6.43 | PSLB | PSLB | – | – | – | – | – | |
15.00 | 127.00 | 22.32 | 7.52 | PSLB | PLB | SLB | PLB | PLB | PLB |   | |
18.00 | 127.00 | 26.79 | 9.19 | – | PLB | SLB | PLB | PLB | PLB | PLB | |
21.40 | 127.00 | 31.85 | 11.10 | – | PLB | PLB | PLB | PLB | PLB | PLB | |
23.20 | 127.00 | 34.53 | 12.14 | – | – | PLB | PLB | PLB | PLB | PLB | |
24.10 | 127.00 | 35.87 | 12.70 | – | – | PLB | PLB | PLB | PLB | PLB | |
5-1/2 | 14.00 | 139.70 | 20.83 | 6.20 | PS | PS | – | – | – | – | – |
15.50 | 139.70 | 23.07 | 6.98 | PSLB | PSLB | – | – | – | – | – | |
17.00 | 139.70 | 25.30 | 7.72 | PSLB | PLB | PLB | PLB | PLB | PLB | – | |
20.00 | 139.70 | 29.76 | 9.17 | – | PLB | PLB | PLB | PLB | PLB | – | |
23.00 | 139.70 | 34.23 | 10.54 | – | PLB | PLB | PLB | PLB | PLB | PLB | |
26.80 | 139.70 | 39.88 | 12.70 | – | – | – | – | P | – | – | |
29.70 | 139.70 | 44.20 | 14.27 | – | – | – | – | P | – | – | |
32.60 | 139.70 | 48.52 | 15.88 | – | – | – | – | P | – | – | |
35.30 | 139.70 | 52.53 | 17.45 | – | – | – | – | P | – | – | |
38.00 | 139.70 | 56.55 | 19.05 | – | – | – | – | P | – | – | |
40.50 | 139.70 | 60.27 | 20.62 | – | – | – | – | P | – | – | |
43.10 | 139.70 | 64.14 | 22.22 | – | – | – | – | P | – | – | |
6-5/8 | 20.00 | 168.28 | 29.76 | 7.32 | PSLB | PSLB | – | – | – | – | – |
24.00 | 168.28 | 35.72 | 8.94 | PSLB | PLB | PLB | PLB | PLB | PLB | – | |
28.00 | 168.28 | 41.67 | 10.59 | – | PLB | PLB | PLB | PLB | PLB | – | |
32.00 | 168.28 | 47.62 | 12.06 | – | – | PLB | PLB | PLB | PLB | PLB | |
7 | 17.00 | 177.80 | 25.30 | 5.87 | – | – | – | – | – | – | – |
20.00 | 177.80 | 29.76 | 6.91 | PS | PS | – | – | – | – | – | |
23.00 | 177.80 | 34.23 | 8.05 | PSLB | PLB | PLB | PLB | PLB | – | – | |
26.00 | 177.80 | 38.69 | 9.19 | – | PLB | PLB | PLB | PLB | PLB | – | |
29.00 | 177.80 | 43.16 | 10.36 | – | PLB | PLB | PLB | PLB | PLB | – | |
32.00 | 177.80 | 47.62 | 11.51 | – | PLB | PLB | PLB | PLB | PLB | – | |
35.00 | 177.80 | 52.09 | 12.65 | – | – | PLB | PLB | PLB | PLB | PLB | |
38.00 | 177.80 | 56.55 | 13.72 | – | – | PLB | PLB | PLB | PLB | PLB | |
42.70 | 177.80 | 63.55 | 15.88 | – | – | – | – | P | – | – | |
46.40 | 177.80 | 69.05 | 17.45 | – | – | – | – | P | – | – | |
50.10 | 177.80 | 74.56 | 19.05 | – | – | – | – | P | – | – | |
53.60 | 177.80 | 79.77 | 20.62 | – | – | – | – | P | – | – | |
57.10 | 177.80 | 84.98 | 22.22 | – | – | – | – | P | – | – | |
7-5/8 | 24.00 | 193.68 | 35.72 | 7.62 | – | – | – | – |   | – | – |
26.40 | 193.68 | 39.29 | 8.33 | PSLB | PSLB | PLB | PLB | PLB | – | – | |
29.70 | 193.68 | 44.20 | 9.52 | – | PLB | PLB | PLB | PLB | PLB | – | |
33.70 | 193.68 | 50.15 | 10.92 | – | PLB | PLB | PLB | PLB | PLB | – | |
39.00 | 193.68 | 58.04 | 12.70 | – | – | PLB | PLB | PLB | PLB | PLB | |
42.80 | 193.68 | 63.69 | 14.27 | – | – | PLB | PLB | PLB | PLB | PLB | |
45.30 | 193.68 | 67.42 | 15.11 | – | – | PLB | PLB | PLB | PLB | PLB | |
47.10 | 193.68 | 70.09 | 15.88 | – | – | PLB | PLB | PLB | PLB | PLB | |
51.20 | 193.68 | 76.20 | 17.45 | – | – | – | – | P | – | – | |
55.30 | 193.68 | 82.30 | 19.05 | – | – | – | – | P | – | – | |
7-3/4 | 46.10 | 196.85 | 68.61 | 15.11 | – | – | P | P | P | P | P |
8-5/8 | 24.00 | 219.08 | 35.72 | 6.71 | PS | PS | – | – | – | – | – |
28.00 | 219.08 | 41.67 | 7.72 |   | PS | – | – | – | – | – | |
32.00 | 219.08 | 47.62 | 8.94 | PSLB | PSLB | – | – | – | – | – | |
36.00 | 219.08 | 53.58 | 10.16 | PSLB | PSLB | PLB | PLB | PLB | PLB | – | |
40.00 | 219.08 | 59.53 | 11.43 | – | PLB | PLB | PLB | PLB | PLB | – | |
44.00 | 219.08 | 65.48 | 12.70 | – | – | PLB | PLB | PLB | PLB | – | |
49.00 | 219.08 | 72.92 | 14.15 | – | – | PLB | PLB | PLB | PLB | PLB | |
9-5/8 | 32.30 | 244.48 | 48.07 | 7.92 | – | – | – | – | – | – | – |
36.00 | 244.48 | 53.58 | 8.94 | PSLB | PSLB | – | – | – | – | – | |
40.00 | 244.48 | 59.53 | 10.03 | PSLB | PSLB | PLB | PLB | PLB | – | – | |
43.50 | 244.48 | 64.74 | 11.05 | – | PLB | PLB | PLB | PLB | PLB | – | |
47.00 | 244.48 | 69.95 | 11.99 | – | PLB | PLB | PLB | PLB | PLB | PLB | |
53.50 | 244.48 | 79.62 | 13.84 | – | – | PLB | PLB | PLB | PLB | PLB | |
58.40 | 244.48 | 86.91 | 15.11 | – | – | PLB | PLB | PLB | PLB | PLB | |
59.40 | 244.48 | 88.40 | 15.47 | – | – | – | – | P | – | – | |
64.90 | 244.48 | 96.58 | 17.07 | – | – | – | – | P | – | – | |
70.30 | 244.48 | 104.62 | 18.64 | – | – | – | – | P | – | – | |
75.60 | 244.48 | 112.51 | 20.24 | – | – | – | – | P | – | – | |
10-3/4 | 32.75 | 273.05 | 48.74 | 7.09 | – | – | – | – | – | – | – |
40.50 | 273.05 | 60.27 | 8.89 | PSB | PSB | – | – | – | – | – | |
45.50 | 273.05 | 67.71 | 10.16 | PSB | PSB | – | – | – | – | – | |
51.00 | 273.05 | 75.90 | 11.43 | PSB | PSB | PSB | PSB | PSB | PSB | – | |
55.50 | 273.05 | 82.60 | 12.57 | – | PSB | PSB | PSB | PSB | PSB | – | |
60.70 | 273.05 | 90.33 | 13.84 | – | – | – | – | PSB | PSB | PSB | |
65.70 | 273.05 | 97.77 | 15.11 | – | – | – | – | PSB | PSB | PSB | |
73.20 | 273.05 | 108.94 | 17.07 | – | – | – | – | P | – | – | |
79.20 | 273.05 | 117.87 | 18.64 | – | – | – | – | P | – | – | |
85.30 | 273.05 | 126.94 | 20.24 | – | – | – | – | P | – | – | |
11-3/4 | 42.00 | 298.45 | 62.50 | 8.46 | – | – | – | – | – | – | – |
47.00 | 298.45 | 69.95 | 9.53 | PSB | PSB | – | – | – | – | – | |
54.00 | 298.45 | 80.36 | 11.05 | PSB | PSB | – | – | – | – | – | |
60.00 | 298.45 | 89.29 | 12.42 | PSB | PSB | PSB | PSB | PSB | PSB | PSB | |
65.00 | 298.45 | 96.73 | 13.56 | – | – | P | P | P | P | P | |
71.00 | 298.45 | 105.66 | 14.78 | – | – | P | P | P | P | P | |
13-3/8 | 48.00 | 339.72 | 71.43 | 8.38 | – | – | – | – | – | – | – |
54.50 | 339.72 | 81.11 | 9.65 | PSB | PSB | – | – | – | – | – | |
61.00 | 339.72 | 90.78 | 10.92 | PSB | PSB | – | – | – | – | – | |
68.00 | 339.72 | 101.20 | 12.19 | PSB | PSB | PSB | PSB | PSB | PSB | – | |
72.00 | 339.72 | 107.15 | 13.06 | – | – | PSB | PSB | PSB | PSB | PSB | |
16 | 65.00 | 406.40 | 96.73 | 9.53 | – | – | – | – | – | – | – |
75.00 | 406.40 | 111.62 | 11.13 | PSB | PSB | – | – | – | – | – | |
84.00 | 406.40 | 125.01 | 12.57 | PSB | PSB | – | – | – | – | – | |
109.00 | 406.40 | 162.21 | 16.66 | P | – | P | P | – | P | P | |
18-5/8 | 87.50 | 473.08 | 130.22 | 11.05 | PSB | PSB | – | – | – | – | – |
20 | 94.00 | 508.00 | 139.89 | 11.13 | PSLB | PSLB | – | – | – | – | – |
106.50 | 508.00 | 158.49 | 12.70 | PSLB | PSLB | – | – | – | – | – | |
133.00 | 508.00 | 197.93 | 16.13 | PSLB | – | – | – | – | – | – |