overview of  API 5ct J55, K55, N80, L80, T95, P110, Q125 Oil Casing grades

API 5CT j55, K55, N80, L80, T95, P110, and Q125 are oil casing grades that are widely used in the Oil and gas industry. These grades are defined by the American petroleum Institute (API) and are designed to meet specific requirements for oil and gas well construction. Silicone TubeJ55 is a commonly used grade that has a minimum yield strength of 55,000 psi. It is suitable for shallow to medium-depth wells and is often used in Casing strings that are not subjected to high internal pressures. K55 is similar to J55 in terms of its yield strength but has a higher tensile strength. This makes it more suitable for wells that require higher pressure containment.
LabelsOutside diameter
(d/mm)
T&C
(kg/m)
Wall thickness  
(t/mm)
type of end-finish
     
12   J55/K55M65L80/ R95N80-1/Q C90/T95P110Q125
4-1/29.50114.3014.145.21PSPS
 10.50114.3015.635.69PSBPSB
 11.60114.3017.266.35PSLBPLBPLBPLBPLBPLB
 13.50114.3020.097.37PLBPLBPLBPLBPLB
 15.10114.3022.478.56PLBPLB
511.50127.0017.115.59PSPS
 13.00127.0019.356.43PSLBPSLB
 15.00127.0022.327.52PSLBPLBSLBPLBPLBPLB 
 18.00127.0026.799.19PLBSLBPLBPLBPLBPLB
 21.40127.0031.8511.10PLBPLBPLBPLBPLBPLB
 23.20127.0034.5312.14PLBPLBPLBPLBPLB
 24.10127.0035.8712.70PLBPLBPLBPLBPLB
5-1/214.00139.7020.836.20PSPS
 15.50139.7023.076.98PSLBPSLB
 17.00139.7025.307.72PSLBPLBPLBPLBPLBPLB
 20.00139.7029.769.17PLBPLBPLBPLBPLB
 23.00139.7034.2310.54PLBPLBPLBPLBPLBPLB
 26.80139.7039.8812.70P
 29.70139.7044.2014.27P
 32.60139.7048.5215.88P
 35.30139.7052.5317.45P
 38.00139.7056.5519.05P
 40.50139.7060.2720.62P
 43.10139.7064.1422.22P
6-5/820.00168.2829.767.32PSLBPSLB
 24.00168.2835.728.94PSLBPLBPLBPLBPLBPLB
 28.00168.2841.6710.59PLBPLBPLBPLBPLB
 32.00168.2847.6212.06PLBPLBPLBPLBPLB
717.00177.8025.305.87
 20.00177.8029.766.91PSPS
 23.00177.8034.238.05PSLBPLBPLBPLBPLB
 26.00177.8038.699.19PLBPLBPLBPLBPLB
 29.00177.8043.1610.36PLBPLBPLBPLBPLB
 32.00177.8047.6211.51PLBPLBPLBPLBPLB
 35.00177.8052.0912.65PLBPLBPLBPLBPLB
 38.00177.8056.5513.72PLBPLBPLBPLBPLB
 42.70177.8063.5515.88P
 46.40177.8069.0517.45P
 50.10177.8074.5619.05P
 53.60177.8079.7720.62P
 57.10177.8084.9822.22P
7-5/824.00193.6835.727.62 
 26.40193.6839.298.33PSLBPSLBPLBPLBPLB
 29.70193.6844.209.52PLBPLBPLBPLBPLB
 33.70193.6850.1510.92PLBPLBPLBPLBPLB
 39.00193.6858.0412.70PLBPLBPLBPLBPLB
 42.80193.6863.6914.27PLBPLBPLBPLBPLB
 45.30193.6867.4215.11PLBPLBPLBPLBPLB
 47.10193.6870.0915.88PLBPLBPLBPLBPLB
 51.20193.6876.2017.45P
 55.30193.6882.3019.05P
7-3/446.10196.8568.6115.11PPPPP
8-5/824.00219.0835.726.71PSPS
 28.00219.0841.677.72 PS
 32.00219.0847.628.94PSLBPSLB
 36.00219.0853.5810.16PSLBPSLBPLBPLBPLBPLB
 40.00219.0859.5311.43PLBPLBPLBPLBPLB
 44.00219.0865.4812.70PLBPLBPLBPLB
 49.00219.0872.9214.15PLBPLBPLBPLBPLB
9-5/832.30244.4848.077.92
 36.00244.4853.588.94PSLBPSLB
 40.00244.4859.5310.03PSLBPSLBPLBPLBPLB
 43.50244.4864.7411.05PLBPLBPLBPLBPLB
 47.00244.4869.9511.99PLBPLBPLBPLBPLBPLB
 53.50244.4879.6213.84PLBPLBPLBPLBPLB
 58.40244.4886.9115.11PLBPLBPLBPLBPLB
 59.40244.4888.4015.47P
 64.90244.4896.5817.07P
 70.30244.48104.6218.64P
 75.60244.48112.5120.24P
10-3/432.75273.0548.747.09
 40.50273.0560.278.89PSBPSB
 45.50273.0567.7110.16PSBPSB
 51.00273.0575.9011.43PSBPSBPSBPSBPSBPSB
 55.50273.0582.6012.57PSBPSBPSBPSBPSB
 60.70273.0590.3313.84PSBPSBPSB
 65.70273.0597.7715.11PSBPSBPSB
 73.20273.05108.9417.07P
 79.20273.05117.8718.64P
 85.30273.05126.9420.24P
11-3/442.00298.4562.508.46
 47.00298.4569.959.53PSBPSB
 54.00298.4580.3611.05PSBPSB
 60.00298.4589.2912.42PSBPSBPSBPSBPSBPSBPSB
 65.00298.4596.7313.56PPPPP
 71.00298.45105.6614.78PPPPP
13-3/848.00339.7271.438.38
 54.50339.7281.119.65PSBPSB
 61.00339.7290.7810.92PSBPSB
 68.00339.72101.2012.19PSBPSBPSBPSBPSBPSB
 72.00339.72107.1513.06PSBPSBPSBPSBPSB
1665.00406.4096.739.53
 75.00406.40111.6211.13PSBPSB
 84.00406.40125.0112.57PSBPSB
 109.00406.40162.2116.66PPPPP
18-5/887.50473.08130.2211.05PSBPSB
2094.00508.00139.8911.13PSLBPSLB
 106.50508.00158.4912.70PSLBPSLB
 133.00508.00197.9316.13PSLB
N80 is a higher strength grade with a minimum yield strength of 80,000 psi. It is commonly used in medium to deep wells and is known for its excellent resistance to corrosion. L80 is another high-strength grade that has a minimum yield strength of 80,000 psi. It is often used in wells that have high internal pressures or are subjected to sour service conditions. T95 is a higher strength grade with a minimum yield strength of 95,000 psi. It is commonly used in deep wells that require high pressure containment. It is also known for its resistance to sulfide stress cracking. P110 is a high-strength grade with a minimum yield strength of 110,000 psi. It is commonly used in deep wells that require high pressure containment and is known for its excellent resistance to corrosion. Q125 is the highest strength grade in the API 5CT specification, with a minimum yield strength of 125,000 psi. It is commonly used in deep wells that require high pressure containment and is known for its excellent resistance to corrosion and sulfide stress cracking. These oil casing grades are manufactured using a variety of processes, including seamless and electric resistance welding (erw). seamless casing is produced by piercing a solid billet of steel and then rolling it into a seamless tube. This process ensures a uniform wall thickness and excellent mechanical properties. erw casing, on the other hand, is produced by forming a strip of steel into a tube and then welding the edges together. This process is more costeffective but may result in slightly lower mechanical properties compared to seamless casing.
alt-2811 In addition to the mechanical properties, these oil casing grades also have specific chemical composition requirements. This ensures that the casing has the necessary strength and Corrosion resistance to withstand the harsh conditions