About Us
Eastern Steel Manufacturing Co.,Ltd is a leading manufacturer and distributor of seamless steel pipe, welded steel pipe, OCTG products and fittings. We supply first-step processing, semi-finished parts and finished parts to help our clients meet fabrication requirements beyond their capacity or to improve operations by moving forward the pre-production processing.
News
In this column you can find the steel pipe related articles you need, including industry trends, product standards and materials, and some technical guidelines.
Services
Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Facility
Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Projects
Many years of large-scale project experience in various fields（Oil & Gas, Construction, Power Energy, Marine & Offshore, Water Treatment, Exploration & Drilling Services, Pipeline & Petrochemical etc.）, professional project team is responsible from receiving until the end of the project.
Steel casing pipe sizes are typically specified by outside diameter, wall thickness, weight per foot, and internal dimensions. These parameters determine the strength, collapse resistance, and installation requirements of the casing string.
The size chart below summarizes common steel casing pipe dimensions used in drilling and well construction projects. In addition to outside diameter and nominal weight, engineers often reference wall thickness, inside diameter, and drift diameter when selecting casing and tubing for a specific application.
The chart covers common API casing sizes together with their corresponding wall thickness, inside diameter, drift diameter, and nominal weight values.
|
Casing Size (in) |
Weight (lb/ft) |
OD (in) |
Wall Thickness (in) |
ID (in) |
Drift Diameter (in) |
Plain End Mass (lb/ft) |
STC (lb) |
LTC (lb) |
BTC-RC (lb |
BTC-SCC (lb) |
|
4 1/2 |
9.5 |
4.5 |
0.205 |
4.09 |
3.965 |
9.41 |
4.2 |
|
|
|
|
4 1/2 |
10.5 |
4.5 |
0.224 |
4.052 |
3.927 |
10.24 |
3.8 |
|
5 |
2.56 |
|
4 1/2 |
11.6 |
4.5 |
0.25 |
4 |
3.875 |
11.36 |
3.4 |
3.8 |
4.6 |
2.16 |
|
4 1/2 |
13.5 |
4.5 |
0.29 |
3.92 |
3.795 |
13.05 |
|
3.2 |
4 |
1.56 |
|
4 1/2 |
15.1 |
4.5 |
0.337 |
3.826 |
3.701 |
15 |
|
2.8 |
3.2 |
0.76 |
|
5 |
11.5 |
5 |
0.22 |
4.56 |
4.435 |
11.24 |
5.4 |
|
|
|
|
5 |
13 |
5 |
0.253 |
4.494 |
4.369 |
12.84 |
4.8 |
5.8 |
6.6 |
2.42 |
|
5 |
15 |
5 |
0.296 |
4.408 |
4.283 |
14.88 |
4.2 |
5.2 |
5.8 |
1.62 |
|
5 |
18 |
5 |
0.362 |
4.276 |
4.151 |
17.95 |
|
4.2 |
4.4 |
0.22 |
|
5 |
21.4 |
5 |
0.437 |
4.126 |
4.001 |
21.32 |
|
2.95 |
2.46 |
-1.72 |
|
5 |
23.2 |
5 |
0.478 |
4.044 |
3.919 |
23.11 |
|
2.3 |
2.05 |
-2.09 |
|
5 |
24.1 |
5 |
0.5 |
4 |
3.875 |
24.05 |
|
1.95 |
1.24 |
-2.94 |
|
5 1/2 |
14 |
5.5 |
0.244 |
5.015 |
4.887 |
13.71 |
5.4 |
|
|
|
|
5 1/2 |
15.5 |
5.5 |
0.275 |
4.95 |
4.825 |
15.36 |
4.8 |
5.8 |
6.4 |
2.1 |
|
5 1/2 |
17 |
5.5 |
0.304 |
4.892 |
4.767 |
16.89 |
4.4 |
5.4 |
5.8 |
1.5 |
|
5 1/2 |
20 |
5.5 |
0.361 |
4.778 |
4.653 |
19.83 |
|
4.4 |
4.6 |
0.3 |
|
5 1/2 |
23 |
5.5 |
0.415 |
4.67 |
4.545 |
22.56 |
|
3.2 |
3.4 |
0.9 |
|
5 1/2 |
26.8 |
5.5 |
0.5 |
4.5 |
4.375 |
26.72 |
|
|
|
|
|
5 1/2 |
29.7 |
5.5 |
0.562 |
4.376 |
4.251 |
29.67 |
|
|
|
|
|
5 1/2 |
32.6 |
5.5 |
0.625 |
4.25 |
4.125 |
32.57 |
|
|
|
|
|
5 1/2 |
35.3 |
5.5 |
0.687 |
4.126 |
4.001 |
35.35 |
|
|
|
|
|
5 1/2 |
38 |
5.5 |
0.75 |
4 |
3.875 |
38.08 |
|
|
|
|
|
5 1/2 |
40.5 |
5.5 |
0.812 |
3.876 |
3.751 |
40.69 |
|
|
|
|
|
5 1/2 |
43.1 |
5.5 |
0.875 |
3.75 |
3.625 |
43.26 |
|
|
|
|
|
6 5/8 |
20 |
6.625 |
0.288 |
6.049 |
5.924 |
19.51 |
11 |
13.6 |
14.4 |
2.38 |
|
6 5/8 |
24 |
6.625 |
0.352 |
5.921 |
5.796 |
23.6 |
9.6 |
12 |
12.6 |
0.58 |
|
6 5/8 |
28 |
6.625 |
0.417 |
5.791 |
5.666 |
27.67 |
|
10.2 |
10.6 |
-1.42 |
|
6 5/8 |
32 |
6.625 |
0.475 |
5.675 |
5.55 |
31.23 |
|
8.8 |
9 |
-3.02 |
|
7 |
17 |
7 |
0.231 |
6.538 |
6.413 |
16.72 |
10 |
|
|
|
|
7 |
20 |
7 |
0.272 |
6.456 |
6.331 |
19.56 |
9.4 |
|
|
|
|
7 |
23 |
7 |
0.317 |
6.366 |
6.25 |
22.65 |
8 |
10.4 |
11 |
1.6 |
|
7 |
23 |
7 |
0.317 |
6.366 |
6.241 |
22.65 |
8 |
10.4 |
11 |
1.6 |
|
7 |
26 |
7 |
0.362 |
6.276 |
6.151 |
25.69 |
7.2 |
9.4 |
9.6 |
0.2 |
|
7 |
29 |
7 |
0.408 |
6.184 |
6.059 |
28.75 |
|
8 |
8.2 |
1.2 |
|
7 |
32 |
7 |
0.453 |
6.094 |
6 |
31.7 |
|
6.6 |
6.8 |
2.6 |
|
7 |
32 |
7 |
0.453 |
6.094 |
5.969 |
31.7 |
|
6.6 |
6.8 |
2.6 |
|
7 |
35 |
7 |
0.498 |
6.004 |
5.879 |
34.61 |
|
5.6 |
5.6 |
3.8 |
|
7 |
38 |
7 |
0.54 |
5.92 |
5.795 |
37.29 |
|
4.4 |
4.2 |
5.2 |
|
7 |
42.7 |
7 |
0.625 |
5.75 |
5.625 |
42.59 |
|
|
|
|
|
7 |
46.4 |
7 |
0.687 |
5.625 |
5.5 |
46.36 |
|
|
|
|
|
7 |
50.1 |
7 |
0.75 |
5.5 |
5.375 |
50.11 |
|
|
|
|
|
7 |
53.6 |
7 |
0.812 |
5.376 |
5.251 |
53.71 |
|
|
|
|
|
7 |
57.1 |
7 |
0.875 |
5.25 |
5.125 |
57.29 |
|
|
|
|
|
7 5/8 |
24 |
7.625 |
0.3 |
7.025 |
6.9 |
23.49 |
15.8 |
|
|
|
|
7 5/8 |
26.4 |
7.625 |
0.328 |
6.969 |
6.844 |
25.59 |
15.2 |
19 |
20.6 |
6.21 |
|
7 5/8 |
29.7 |
7.625 |
0.375 |
6.875 |
6.75 |
29.06 |
|
17.4 |
18.8 |
4.41 |
|
7 5/8 |
33.7 |
7.625 |
0.43 |
6.765 |
6.64 |
33.07 |
|
15.8 |
17 |
2.61 |
|
7 5/8 |
39 |
7.625 |
0.5 |
6.625 |
6.5 |
38.08 |
|
13.6 |
14.6 |
0.21 |
|
7 5/8 |
42.8 |
7.625 |
0.562 |
6.501 |
6.376 |
42.43 |
|
12.01 |
11.39 |
-3.01 |
|
7 5/8 |
45.3 |
7.625 |
0.595 |
6.435 |
6.31 |
44.71 |
|
11.04 |
11.04 |
-3.36 |
|
7 5/8 |
47.1 |
7.625 |
0.625 |
6.375 |
6.25 |
46.77 |
|
10.16 |
9.23 |
-5.17 |
|
7 5/8 |
51.2 |
7.625 |
0.687 |
6.251 |
6.126 |
50.95 |
|
|
|
|
|
7 5/8 |
55.3 |
7.625 |
0.75 |
6.125 |
6 |
55.12 |
|
|
|
|
|
7 3/4 |
46.1 |
7.75 |
0.595 |
6.56 |
6.5 |
45.51 |
|
|
|
|
|
7 3/4 |
46.1 |
7.75 |
0.595 |
6.56 |
6.435 |
45.51 |
|
|
|
|
|
8 5/8 |
24 |
8.625 |
0.264 |
8.097 |
7.972 |
23.6 |
23.6 |
|
|
|
|
8 5/8 |
28 |
8.625 |
0.304 |
8.017 |
7.892 |
27.04 |
22.2 |
|
|
|
|
8 5/8 |
32 |
8.625 |
0.352 |
7.921 |
7.875 |
31.13 |
20.8 |
27.6 |
28.3 |
6.03 |
|
8 5/8 |
32 |
8.625 |
0.352 |
7.921 |
7.796 |
31.13 |
20.8 |
27.6 |
28.2 |
6.03 |
|
8 5/8 |
36 |
8.625 |
0.4 |
7.825 |
7.7 |
35.17 |
19.4 |
25.6 |
26.2 |
4.03 |
|
8 5/8 |
40 |
8.625 |
0.45 |
7.725 |
7.625 |
39.33 |
|
23.8 |
24.2 |
2.03 |
|
8 5/8 |
40 |
8.625 |
0.45 |
7.725 |
7.6 |
39.33 |
|
23.8 |
24.2 |
2.03 |
|
8 5/8 |
44 |
8.625 |
0.5 |
7.625 |
7.5 |
43.43 |
|
21.8 |
22.2 |
0.03 |
|
8 5/8 |
49 |
8.625 |
0.557 |
7.511 |
7.286 |
48.04 |
|
19.6 |
19.8 |
-2.37 |
|
9 5/8 |
32.3 |
9.625 |
0.312 |
9.001 |
8.845 |
31.06 |
24.4 |
|
|
|
|
9 5/8 |
36 |
9.625 |
0.352 |
8.921 |
8.876 |
34.89 |
23 |
32 |
31 |
6.48 |
|
9 5/8 |
40 |
9.625 |
0.395 |
8.835 |
8.75 |
38.97 |
21.4 |
30 |
29 |
4.48 |
|
9 5/8 |
40 |
9.625 |
0.395 |
8.835 |
8.679 |
38.97 |
21.4 |
30 |
29 |
4.48 |
|
9 5/8 |
43.5 |
9.625 |
0.435 |
8.755 |
8.599 |
42.73 |
|
28.2 |
27.2 |
2.68 |
|
9 5/8 |
47 |
9.625 |
0.472 |
8.681 |
8.525 |
46.18 |
|
26.6 |
25.6 |
1.08 |
|
9 5/8 |
53.5 |
9.625 |
0.545 |
8.535 |
8.5 |
52.9 |
|
23.4 |
22.4 |
-2.12 |
|
9 5/8 |
53.5 |
9.625 |
0.545 |
8.535 |
8.379 |
52.9 |
|
23.4 |
22.4 |
-2.12 |
|
9 5/8 |
58.4 |
9.625 |
0.595 |
8.435 |
8.375 |
57.44 |
|
21.5 |
20.13 |
-4.4 |
|
9 5/8 |
58.4 |
9.625 |
0.595 |
8.435 |
8.279 |
57.44 |
|
21.5 |
20.13 |
-4.4 |
|
9 5/8 |
59.4 |
9.625 |
0.609 |
8.407 |
8.251 |
58.7 |
|
|
|
|
|
9 5/8 |
64.9 |
9.625 |
0.672 |
8.281 |
8.125 |
64.32 |
|
|
|
|
|
9 5/8 |
70.3 |
9.625 |
0.734 |
8.157 |
8.001 |
69.76 |
|
|
|
|
|
9 5/8 |
75.6 |
9.625 |
0.797 |
8.031 |
7.875 |
75.21 |
|
|
|
|
|
10 3/4 |
32.75 |
10.75 |
0.279 |
10.192 |
10.036 |
31.23 |
29 |
|
|
|
|
10 3/4 |
40.5 |
10.75 |
0.35 |
10.05 |
9.894 |
38.91 |
26.4 |
|
34.4 |
7.21 |
|
10 3/4 |
45.5 |
10.75 |
0.4 |
9.95 |
9.875 |
44.26 |
24.4 |
|
31.8 |
4.61 |
|
10 3/4 |
45.5 |
10.75 |
0.4 |
9.95 |
9.794 |
44.26 |
24.4 |
|
31.8 |
4.61 |
|
10 3/4 |
51 |
10.75 |
0.45 |
9.85 |
9.694 |
49.55 |
22.6 |
|
29.4 |
2.21 |
|
10 3/4 |
55.5 |
10.75 |
0.495 |
9.76 |
9.625 |
54.26 |
20.8 |
|
27 |
-0.19 |
|
10 3/4 |
55.5 |
10.75 |
0.495 |
9.76 |
9.604 |
54.26 |
20.8 |
|
27 |
-0.19 |
|
10 3/4 |
60.7 |
10.75 |
0.545 |
9.66 |
9.504 |
59.45 |
18.8 |
|
24.4 |
|
|
10 3/4 |
65.7 |
10.75 |
0.595 |
9.56 |
9.404 |
64.59 |
16.8 |
|
22 |
|
|
10 3/4 |
73.2 |
10.75 |
0.672 |
9.406 |
9.25 |
72.4 |
|
|
|
|
|
10 3/4 |
79.2 |
10.75 |
0.734 |
9.282 |
9.126 |
78.59 |
|
|
|
|
|
10 3/4 |
85.3 |
10.75 |
0.797 |
9.156 |
9 |
84.8 |
|
|
|
|
|
11 3/4 |
42 |
11.75 |
0.333 |
11.084 |
11 |
40.64 |
29.6 |
|
|
|
|
11 3/4 |
42 |
11.75 |
0.333 |
11.084 |
10.928 |
40.64 |
29.6 |
|
|
|
|
11 3/4 |
47 |
11.75 |
0.375 |
11 |
10.844 |
45.6 |
27.6 |
|
35.8 |
|
|
11 3/4 |
54 |
11.75 |
0.435 |
10.88 |
10.724 |
52.62 |
25 |
|
32.4 |
|
|
11 3/4 |
60 |
11.75 |
0.489 |
10.772 |
10.625 |
58.87 |
22.6 |
|
29.6 |
|
|
11 3/4 |
60 |
11.75 |
0.489 |
10.772 |
10.616 |
58.87 |
22.6 |
|
29.6 |
|
|
11 3/4 |
65 |
11.75 |
0.534 |
10.682 |
10.625 |
64.03 |
|
|
|
|
|
11 3/4 |
65 |
11.75 |
0.534 |
10.682 |
10.625 |
64.03 |
|
|
|
|
|
11 3/4 |
71 |
11.75 |
0.582 |
10.586 |
10.43 |
69.48 |
|
|
|
|
|
13 3/8 |
48 |
13.375 |
0.33 |
12.715 |
12.559 |
46.02 |
33.2 |
|
|
|
|
13 3/8 |
54.5 |
13.375 |
0.38 |
12.615 |
12.459 |
52.79 |
30.8 |
|
40.2 |
|
|
13 3/8 |
61 |
13.375 |
0.43 |
12.515 |
12.359 |
59.5 |
28.4 |
|
36.8 |
|
|
13 3/8 |
68 |
13.375 |
0.48 |
12.415 |
12.259 |
66.17 |
25.8 |
|
33.6 |
|
|
13 3/8 |
72 |
13.375 |
0.514 |
12.347 |
12.25 |
70.67 |
24.2 |
|
31.6 |
|
|
13 3/8 |
72 |
13.375 |
0.514 |
12.347 |
12.191 |
70.67 |
24.2 |
|
31.6 |
|
|
16 |
65 |
16 |
0.375 |
15.25 |
15.062 |
62.64 |
42.6 |
|
|
|
|
16 |
75 |
16 |
0.438 |
15.124 |
14.936 |
72.86 |
38.2 |
|
45.6 |
|
|
16 |
84 |
16 |
0.495 |
15.01 |
14.822 |
82.05 |
34.2 |
|
39.6 |
|
|
16 |
109 |
16 |
0.656 |
14.688 |
14.5 |
107.6 |
|
|
|
|
|
18 5/8 |
87.5 |
18.625 |
0.435 |
17.755 |
17.567 |
84.59 |
73.6 |
|
86.4 |
|
|
20 |
94 |
20 |
0.438 |
19.124 |
18.936 |
91.59 |
47 |
61.2 |
54.8 |
|
|
20 |
106.5 |
20 |
0.5 |
19 |
18.812 |
104.23 |
41.6 |
54.8 |
48.4 |
|
|
20 |
133 |
20 |
0.635 |
18.73 |
18.542 |
131.45 |
30 |
40.6 |
35.2 |
|
When selecting steel casing pipe, engineers typically evaluate several key dimensions. Understanding these parameters helps ensure the casing can meet installation, load, and operational requirements.
Outside diameter refers to the overall external diameter of the casing pipe. Casing sizes such as 4-1/2", 7", and 9-5/8" are identified by their OD.
Nominal weight indicates the theoretical pipe weight per foot. A higher weight generally corresponds to a thicker wall and greater collapse resistance.
Wall thickness is the distance between the outside and inside surfaces of the pipe. Different wall thicknesses may be available for the same casing size.
Inside diameter represents the available internal flow area of the casing. It decreases as wall thickness increases.
Drift diameter is the minimum internal diameter through which a standard drift mandrel can pass. It is commonly used to verify casing clearance before running downhole equipment.
For water well projects, casing sizes between 4" and 12" are commonly used. Residential wells often use 4" to 6" casing, while larger municipal and irrigation wells may require 8" to 12" diameters to accommodate higher pumping capacities.
Oil and gas wells normally use several casing strings of progressively smaller diameters from the surface to the production zone.
Common examples include 13-3/8" surface casing, 9-5/8" intermediate casing, and 4-1/2" or 5-1/2" production casing.
Borehole casing is commonly used in groundwater investigation, monitoring wells, environmental sampling, and geotechnical drilling projects.Depending on the borehole design, casing sizes typically range from 4" to 10", with larger diameters often selected when additional instrumentation or higher water flow capacity is required.
Conductor casing is the first casing string installed during drilling operations. Large diameters such as 16", 18-5/8", and 20" are commonly used to support shallow formations, prevent surface collapse, and provide a stable foundation for subsequent casing strings.
Although API casing is available in a wide range of diameters, several sizes are used more frequently in drilling and well construction projects. The table below summarizes common casing sizes and their typical applications.
Casing Size Common Application
4-1/2" Production casing
5-1/2" Oil & gas wells
7" Intermediate casing
9-5/8" Surface casing
13-3/8" Surface casing
20" Conductor casing
In most drilling projects, multiple casing sizes are installed sequentially to provide structural support, isolate formations, and maintain wellbore integrity throughout drilling and production operations.
Q1. How is casing pipe size measured?
Casing size is generally identified by its outside diameter (OD). Additional dimensions such as wall thickness, inside diameter (ID), and drift diameter are used to define the complete casing specification.
Q2. What is the difference between casing size and inside diameter?
Casing size refers to the nominal outside diameter of the pipe, while inside diameter represents the usable internal opening. For the same casing size, the ID changes as wall thickness increases or decreases.
Q3. Why does the inside diameter change while the outside diameter remains the same?
API casing is classified by outside diameter. Different weight options are available for the same OD, resulting in different wall thicknesses and therefore different inside diameters.
Q4. What is drift diameter in steel casing pipe?
Drift diameter is the minimum internal diameter through which a standard drift mandrel can pass. It is used to verify that downhole tools and equipment can move through the casing without obstruction.
Q5. Can the same casing size have different weights?
Yes. A single casing size may be produced with multiple wall thicknesses and nominal weights. For example, 7" casing is available in several weight grades, each providing different strength and internal dimensions.
Q6. What casing sizes are commonly used for water wells?
Water well casing typically ranges from 4 inches to 12 inches in diameter. The selected size depends on well depth, pump capacity, and required water production.
Q7. What are the standard steel casing pipe sizes?
Standard API casing sizes range from 4-1/2" to 20" OD. Common sizes include 4-1/2", 5-1/2", 7", 9-5/8", 13-3/8", and 20", depending on the well design and application requirements.
For additional sizing and specification information, refer to the following resources:
Steel Casing Pipe Weight Chart
Steel Casing Pipe Wall Thickness
Applications of Steel Casing Pipe
How To Choose The Size of Steel Casing Pipe?
E-mail: sales@eastern-steels.com
