J55 Casing is a casing grade defined by the API (American Petroleum Institute) standard, made of high-quality carbon structural steel, with the domestic equivalent steel grade being the DZ series.
API 5CT J55 casing is primarily used to support wellbore walls, isolate formation pressures, and transport oil and gas, and is widely applied in oil wells, gas wells, geothermal wells, and other scenarios.
Its outer diameter ranges from 139.7 to 244.5 mm, with a wall thickness of 7.72 to 11.05 mm, and is available in three length categories:
R-1 (4.88–7.62 m)
R-2 (7.62–10.36 m)
R-3 (10.36 m and above)
J55 Casing Specification
Standard: API 5CT
Grade: J55
Tolerance.
OD＜114.3mm tolerance ±0.79
OD≥114.3mm tolerance -0.5% +1%
Thickness tolerance:-12.5%
Applications: Shallow wells, geothermal wells, and water wells or other oil wells
Threads type: short round thread, long round thread, Buttress thread, Premium thread, etc.
Weight calculation：
[(outer diameter - wall thickness) * wall thickness] * 0.02466 = kg / m (weight per meter)
chemical composition
(1) According to SY/T6194-96. The casing and its couplings are of the same steel grade. Sulfur content <0.045%, phosphorus content <0.045%;
(2) Take chemical analysis samples according to the provisions of GB/T222-84. Conduct chemical analysis according to the relevant provisions of GB223;
(3) American Petroleum Institute API SPEC 5CT 1988 first edition. Chemical analysis was prepared according to the latest version of ASTM E59 and chemical analysis was performed according to the latest version of ASTM E350.
Physical properties
(1) According to SY/T6194-96. For the flattening test (GB246-97) tensile test (GB228-87) and hydraulic test;
(2) According to the American Petroleum Institute API SPEC 5CT 1988 first edition for hydrostatic pressure test, flattening test, sulfide stress corrosion cracking test, hardness test (ASTME18 or E10 latest version of the provisions), tensile test, lateral impact test ( ASTMA370, ASTME23 and the latest edition of the relevant standards are specified), grain size determination (the latest version of ASTM E112 or other methods).
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