Casing pup joint ensures the continuity of downhole casing through threaded connections, playing a critical role in reinforcing the wellbore and sealing oil/gas reservoirs in well structures.
Per API 5CT standards, pup joints are manufactured from carbon steel or alloy steel, with common materials including specialized grades like L80-13Cr. The production process encompasses raw material preparation, thread forming, and surface treatment

Specification of Casing pup joints
| OD | GRADE | END TYPE |
| 4 1/2″ | J/K/L/N/P | LTC/STC/BTC |
| 5″ | J/K/L/N/P | LTC/STC/BTC |
| 5 1/2″ | J/K/L/N/P | LTC/STC/BTC |
| 6 5/8″ | J/K/L/N/P | LTC/STC/BTC |
| 7″ | J/K/L/N/P | LTC/STC/BTC |
| 7 5/8″ | J/K/L/N/P | LTC/STC/BTC |
| 7 3/4″ | J/K/L/N/P | LTC/STC/BTC |
| 8 5/8″ | J/K/L/N/P | LTC/STC/BTC |
| 9 5/8″ | J/K/L/N/P | LTC/STC/BTC |
| 10 3/4″ | J/K/L/N/P | STC/BTC |
| 11 3/4″ | J/K/L/N/P | STC/BTC |
| 13 3/8″ | J/K/L/N/P | STC/BTC |





