Perforated Pup Joint

　　Function:

　　(1) Flow Channel Control

　　Pressure Balancing: During completion or production phases, it allows formation fluids to enter the tubing string (e.g., in screen assemblies) through perforations or enables fluid injection into the formation (e.g., in water injection wells).

　　Turbulence Reduction: The perforation design helps distribute fluid flow, minimizing erosion caused by high-velocity fluids on the tubing string.

　　(2) Sand Control or Filtration

　　When used in combination with screens or gravel packs, the perforation structure prevents larger sand particles from entering the tubing string while permitting fluid flow.