API Casing Specification Chart

Oilfield Chart - API Casing Specification ChartThe API Casing Specification Chart provides specific data that is essential before any operation begins. It includes different casing sizes and capacities that would define a casing’s limitations. Casings are also known as Encasement pipe, which comprises steel tubes that are utilized for gas and oil underground operations. It protects a utility system from detrimental factors.

API Casing Specification Discussion

Pipe casing plays a huge role in underground operations and is also considered an important material in wells. Another function of the casing is to keep the stability of a borehole, control the pressure during the entire process, and prevent the contamination of water sands.

Listed are the types of pipe casing used in the industry:

Conductor Casing

This casing must be installed before the drilling rig. This is usually placed through a drill with a small auger. Its length is not more than 50 feet.

Surface Casing

This extends up to 2,000 feet long and has a smaller diameter compared to conductor casing. Its function is to keep the water deposits from being contaminated by the presence of salt water or hydrocarbons below the surface.

Intermediate Casing

This is where the longest section is found in a well. Similar to other kinds of casing, it protects the well from any harmful factors–for instance, underground shale, contaminating elements, below-the-ground pressure zones, and salt water deposits.

Liner

This is commonly preferred over intermediate casing. It runs a casing bottom through an open well area.

Production casing

This casing is found in the deepest section and is installed last. Its size usually depends on many factors, such as the possibility of deepening the well in the future and the equipment utilized during the process.

Aside from these, the pipe casings are made from different grades, which affect their efficiency and durability.

Grade Yield Strength Min. Tensile Strength API Color Code
wdt_ID Grade Yield Strength Min. Tensile Strength API Color Code
1 J55 379-552 MPa (55-80 ksi) 517 MPa (75 ksi) 1 bright green band
2 K55 379-552 MPa (55-80 ksi) 665 MPa (95 ksi) 2 bright green bands
3 N80 552-758 MPa (55-80 ksi) 689 MPa (100 ksi) 1 red (N80-1), 1 red band + 1 bright green band (N80-Q)
4 L80 552-665 MPa (80-95 ksi) 655 MPa (95 ksi) 1 red + 1 brown (L80), 1 red + 1 brown + 2 yellow (L80 9Cr), 1 red + 1 brown + 1 yellow (L80 13Cr)
5 P110 758-965 MPa (110-140 ksi) 862 MPa (125 ksi) 1 white band
 

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API Casing Specification Chart

wdt_ID Size (in) Size (mm) Wgt (lb/ft) ID (in) ID (mm) Drift (in) Drift (mm) Capacity (bbl/100ft)
1 4 1/2 114.30 9.50 4.090 103.89 3.965 100.71 1.63
2 10. 50 4.052 102.92 3.927 99. 75 1.59
4 11. 60 4.000 101.60 3.875 98. 43 1.55
5 12. 60 3.958 100.53 3.833 97. 36 1.52
6 13. 50 3.920 99. 57 3.795 96. 39 1.49
7 15. 10 3.826 97. 18 3.701 94. 01 1.42
8 16. 60 3.754 95. 35 3.629 92. 18 1.37
9 16. 90 3.740 95. 00 3.615 91. 82 1.36
10 17. 70 3.696 93. 88 3.571 90. 70 1.33
11 18. 80 3.640 92. 46 3.515 89. 28 1.29
12 21. 60 3.500 88. 90 3.375 85. 73 1.19
13 24. 60 3.380 85. 85 3.255 82. 68 1.11
14 26. 50 3.240 82. 30 3.115 79. 12 1.02
15 5 127.00 11. 50 4.560 115.82 4.435 112.65 2.02
16 13. 00 4.494 114.15 4.369 110.97 1.96
17 15. 00 4.408 111.96 4.283 108.79 1.89
18 18. 00 4.276 108.61 4.151 105.44 1.78
19 20. 30 4.184 106.27 4.059 103.10 1.70
20 20. 80 4.156 105.56 4.031 102.39 1.68
21 21. 40 4.126 104.80 4.001 101.63 1.65
22 23. 20 4.044 102.72 3.919 99. 54 1.59
23 24. 20 4.000 101.60 3.875 98. 43 1.55
24 26. 70 3.876 98. 45 3.751 95. 28 1.46
25 32. 00 3.620 91. 95 3.495 88. 77 1.27
26 5 1/2 139.70 13. 00 5.044 128.12 4.919 124.94 2.47
27 14. 00 5.012 127.30 4.887 124.13 2.44
28 15. 50 4.950 125.73 4.825 122.56 2.38
29 17. 00 4.892 124.26 4.767 121.08 2.32
30 20. 00 4.778 121.36 4.653 118.19 2.22
31 23. 00 4.670 118.62 4.545 115.44 2.12
32 26. 00 4.548 115.52 4.423 112.34 2.01
33 28. 40 4.440 112.78 4.315 109.60 1.91
34 29. 70 4.376 111.15 4.251 107.98 1.86
35 32. 30 4.276 108.61 4.151 105.44 1.78
36 36. 40 4.090 103.89 3.965 100.71 1.62
37 39. 30 4.044 102.72 3.919 79. 54 1.59
38 6 152.40 15. 00 5.542 140.77 5.399 137.13 2.98
39 18. 00 5.424 137.77 5.299 134.59 2.86
40 20. 00 5.352 135.94 5.227 132.77 2.78
41 23. 00 5.240 133.10 5.115 129.92 2.67
42 26. 00 5.132 130.35 5.007 127.18 2.56
43 6 5/8 168.28 17. 00 6.135 155.83 6.010 152.65 3.66
44 20. 00 6.049 153.64 5.924 150.47 3.55
45 24. 00 5.921 150.39 5.796 147.22 3.41
46 28. 00 5.791 147.09 5.666 143.92 3.26
47 32. 00 5.675 144.15 5.550 140.97 3.13
48 35. 00 5.575 141.61 5.450 138.43 3.02
49 43. 20 5.375 136.53 5.250 133.35 2.81
50 69. 63 4.375 111.13 4.250 107.95 1.86
51 7 177.80 17. 00 6.538 166.07 6.413 162.89 4.15

API Casing Chart Abbreviations:

  • I.D. – Inside Diameter
  • in – inch
  • mmmillimeter
  • lbs/ft – pounds per feet
  • bbl/100ft – barrel per 100 feet

API Casing Specification

Casings are specified by their size, weight, and grade.

  • Nominal weight refers to the tubing’s linear weight. It also defines its wall thickness
  • ID refers to the inner diameter
  • The drift diameter is commonly 1/8 (3.2mm) and less than ID
  • Yield Strength is expressed in ksi (kilograms per square inch) or MPa -megapascals

1MPa= 1,000,000 pascals (a unit used to describe pressure ranges in hydraulic systems)

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