Pup joint of tubing refers to tubing shorter than R1. Its length is usually 0.3 meters-6 meters or 1FT-20FT. The basic specifications, steel grade, and operating environment are the same as ordinary tubing. The pipe body implements the API Spec-5CT 9th. Thread processing executes API Spec-5B. Types are divided into: Pup joint is divided into ordinary pup joint, double male pup joint, and overall thickening pup joint.
  Tubing pup joint, mainly used for oil, natural gas, shale gas/shale, wear-resistant pup joint, direct connection to large-end tubing pup joint, coalbed methane, hot springs, geothermal exploitation .
  ① Extracting oil and gas: After the gas well is drilled and cemented, a pup joint is placed in the oil layer casing to extract oil and gas to the surface.
  ② Water injection: When the downhole pressure is not enough, inject water into the well through pup joint.
  ③ Steam injection: In the process of thermal recovery of heavy oil, heat insulation pup joint should be used to input steam downhole.
  ④ Acidification and fracturing: In the later stage of well drilling or in order to increase the production of oil and gas wells, it is necessary to input acidizing and fracturing media or solidifications into the oil and gas layer. media and solidifications are all transported through pup joint.