A pup joint is a short, non-standard length of pipe (casing, tubing, or drill pipe) used in oil & gas operations to precisely adjust the total length of tubular strings, ensuring proper placement of downhole tools or achieving exact depth, acting as a spacer or “saver sub” in various high-pressure applications like drilling, cementing, and well servicing.
Key Functions & Characteristics:
- Spacing & Adjustment: Used to “space out” or make up the precise length needed for casing, tubing, or drill strings, preventing gaps or over-lengths.
- Variable Lengths: Available in shorter lengths (e.g., 2, 3, 4, 6, 10, 12 feet) than standard pipe, with custom lengths possible.
- Material & Strength: Made from seamless steel, matching the strength (J55, N80, P110, etc.) and thread type (like 8RD, BTC) of the main pipe string.
- Applications: Essential for handling production tubing, high-pressure fracturing lines, cementing, choke & kill lines, and other flow systems.
Common Uses:
- Drilling: Adjusting drill string length.
- Casing/Tubing Strings: Fine-tuning placement in the wellbore.
- Pressure Control: Providing specific length in high-pressure equipment.
In essence, a pup joint adds a small, specific length to a pipe assembly to meet exact operational requirements in complex well environments.
