Types of Casing pipe:
Seamless casing (small-diameter, medium-diameter)
ERW casing (medium-diameter)
Casing nipple
Casing coupling
Applications of casing pipe:
oil well extracting casing
borehole casing
borewell casing
Connections of casing pipe
API 5CT is applicable to following connections which complied with API SPEC 5B:
• SC: Short round thread casing
• LC: Long ound thread casing
• BC: Buttress thread casing
• NU: Non-upset tubing
• EU: External upset tubing
• IJ: Integral tubing connections
4 Groups of Grade
• Group 1: All casing and tubing in Grades with H, J, K, N and R
• Group 2: All casing and tubing in Grades with C, L, M and T
• Group 3: All casing and tubing in Grade P
• Group 4: All casing in Grade Q
Chemical Composition of API 5CT steel casing and tubing pipes:
Chemical composition,mass fraction(%) | |||||||||||||||
Group | Grade | Type | C | Mn | Mo | Cr | Ni | Cu | P | S | Si | ||||
Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Max. | Max. | Max. | Max. | Max. | |||
1 | H40 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – |
J55 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – | |
K55 | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – | ||||
N80 | 1 | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – | |
N80 | Q | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – | |
R95 | – | – | 0.45 | – | 1.90 | – | – | – | – | – | – | 0.03 | 0.030 | 0.45 | |
2 | M65 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – |
L80 | 1 | – | 0.43 | – | 1.90 | – | – | – | – | 0.25 | 0.35 | 0.03 | 0.030 | 0.45 | |
L80 | 9Cr | – | 0.15 | 0.30 | 0.60 | 0.90 | 1.10 | 8.00 | 10.00 | 0.50 | 0.25 | 0.02 | 0.010 | 1.00 | |
L80 | 13Cr | 0.15 | 0.22 | 0.25 | 1.00 | – | – | 12.00 | 14.00 | 0.50 | 0.25 | 0.02 | 0.010 | 1.00 | |
C90 | 1 | – | 0.35 | – | 1.20 | 0.25 | 0.85 | – | 1.50 | 0.99 | – | 0.02 | 0.010 | – | |
T95 | 1 | – | 0.35 | – | 1.20 | 0.25 | 0.85 | 0.40 | 1.50 | 0.99 | – | 0.02 | 0.010 | – | |
C110 | – | – | 0.35 | – | 1.20 | 0.25 | 1.00 | 0.40 | 1.50 | 0.99 | – | 0.02 | 0.005 | – | |
3 | P110 | – | – | – | – | – | – | – | – | – | – | – | 0.03 | 0.030 | – |
4 | Q125 | 1 | – | 0.35 | – | 1.35 | – | 0.85 | – | 1.50 | 0.99 | – | 0.02 | 0.010 | – |
Mechanical Properties of API 5CT steel casing and tubing pipes:
Mechanical Properties | ||||||||
Group | Steel Grade | Type | Total | Yield Strength (Mpa) | Tensile Strength (Mpa) | Hardness max. | ||
% | min. | max. | MPa | HRC | HWB | |||
1 | H40 | – | 0.5 | 276 | 552 | 414 | – | – |
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 | – | – | |
R95 | – | 0.5 | 655 | 758 | 724 | – | – | |
2 | M65 | – | 0.5 | 448 | 586 | 586 | 22 | 235 |
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 | 1 | 0.5 | 621 | 724 | 689 | 25.4 | 255 | |
T95 | 1 | 0.5 | 655 | 758 | 724 | 25.4 | 255 | |
C110 | – | 0.7 | 758 | 828 | 793 | 30 | 286 | |
3 | P110 | – | 0.6 | 758 | 965 | 862 | – | – |
4 | Q125 | 1 | 0.65 | 862 | 1034 | 931 | – |
Size table of casing pipe
Outside Diameter (Inches) |
Available Poundage (Pounds Per Foot) |
4-1/2 |
9.50 PPF to 15.10 PPF |
5 |
11.50 PPF to 24.10 PPF |
5-1/2 |
14.00 PPF to 43.10 PPF |
6-5/8 |
20.00 PPF to 32.00 PPF |
7 |
17.00 PPF to 57.10 PPF |
7-5/8 |
24.00 PPF to 55.30 PPF |
7-3/4 |
46.10 PPF |
8-5/8 |
24.00 PPF to 49.00 PPF |
9-5/8 |
32.30 PPF to 75.60 PPF |
10-3/4 |
32.75 PPF to 85.30 PPF |
11-3/4 |
42.00 PPF to 71.00 PPF |
13-3/8 |
48.00 PPF to 72.00 PPF |
16 |
65.00 PPF to 109.00 PPF |
18-5/8 |
87.50 PPF |
20 |
94.00 PPF to 133.00 PPF |
Size table of tubing
Outside Diameter (Inches) |
Corresponding Poundage (Pounds Per Foot) |
1.050 |
1.14 PPF to 1.54 PPF |
1.315 |
1.70 PPF to 2.24 PPF |
1.660 |
2.09 PPF to 3.07 PPF |
1.900 |
2.40 PPF to 5.15 PPF |
2.063 |
3.24 PPF to 4.50 PPF |
2-3/8 |
4.00 PPF to 7.45 PPF |
2-7/8 |
6.40 PPF to 11.50 PPF |
3-1/2 |
7.70 PPF to 17.00 PPF |
4 |
9.50 PPF to 22.20 PPF |
4-1/2 |
12.60 PPF to 26.10 PPF |
Casing Pipe, also known as production Casing Pipe. It is the last layer of Casing Pipe in the oil and gas well Casing Pipe program, which goes down from the wellhead to below the oil and gas layer that passes through. The depth at which the oil layer Casing Pipe is run is basically the depth of the well. The role of the oil layer Casing Pipe is to channel the oil and gas to the ground, to isolate the oil and gas from all formations, and to ensure that the oil and gas pressure does not leak. After the oil layer Casing Pipe is put into production, its quality must be guaranteed to maintain a certain production life.
On the one hand, the cementing quality of oil layer Casing Pipe is related to the exploration well, which is the key to oil and gas testing; on the other hand, it is related to the production well, which directly affects the life of the well. The cement plugging height of the gap between the oil layer Casing Pipe and the well wall is at least 500 meters above the oil and gas layer, or up to 200 meters inside the upper layer of Casing Pipe.
Grades of Casing pipe:
API 5CT H40
API 5CT J55
API 5CT K55
API 5CT M65
API 5CT N80 (1,Q)
API 5CT L80 (9Cr,13Cr)
API 5CT C90
API 5CT T95
API 5CT P110
API 5CT Q125