Hydraulic Jar


The Weatherford hydraulic jar provides reliability and long operating life under a wide range of well conditions, including deep, deviated high-temperature wells. It delivers controlled jarring action without compromising performance.

This straight-pull-operated jar uses a combination hydraulic time-delay/mechanical-trigger system and can transmit torque to the right at any position along its stroke. Jarring load is controlled and varied at surface by overpull. The greater the overpull, the faster the jar hits, and the higher the impact load. With large, free-flow paths, the jar can be reset as fast as the string can be lowered without damage to the internal seals or housing. Resetting does not require preloading─only enough weight to overcome internal seal friction.


  • Drillstem testing
  • Production testing
  • Perforating operations
  • Stimulation

Features, Advantages and Benefits

  • One-piece splined mandrel provides effective transfer of torque through the hydraulic jar.
  • High-pressure fluid chamber lubricates and isolates the dynamic seals, impact shoulders, and mandrel from downhole debris, which protects the operational integrity of the jar.
  • Impact times and loads are controlled by increasing or decreasing the applied overpull on the string, and that provides operational flexibility.
  • Fullbore ID of the jar facilitates unrestricted flow and access for well interventions.