Feature overview

• When in neutral position, mechanical latch prevents jar from jarring unexpectedly while handling and drilling
  • Fewer jars extends life of the tool
  • Enhances handling safety
  • Allows tool to be shipped into any region
• Spline drive and latch mechanism enclosed in a single, sealed oil chamber without ports to annulus
  • No ports that could fill with cuttings and restrict down stroke
  • Fluid and debris kept out of internal mechanisms
• Hydraulically controlled by an internal metering device
  • Metering device kept in separate oil sealed chamber to prevent contamination
  • Ensures consistent delay over the full range of operating temperatures
  • Impact force controlled by operator
• With latch mechanism engaged, the inner mandrel and outer housing act integrally, virtually eliminating seal and inner tool wear during normal drilling conditions
• No need to extend or open the jar before running in the hole
• Jars in both directions: mechanically down, and with hydraulic delay up
• Operates via up and down motion
• Can be run in tension or compression within the preset latch setting
• Unaffected by right- and left-hand torque
• If needed, UHMJ can easily be converted to the conventional HMJ configuration
• Standard seals are suitable for use up to 250ºF (120ºC); optional high temperature seal kits are available for service to 400ºF (200ºC)
• External sealing surfaces are tungsten-carbide coated to enhance wear and corrosion resistance

Operation

When jarring up:

• Apply sufficient overpull to overcome the latch setting. This will initiate the hydraulic time delay.
• During time delay, overpull can be adjusted at surface to vary the impact force.
• After impact, apply a down force sufficient to close jar and re-engage latch, then repeat the jarring cycle as required.

When jarring down:

• Apply sufficient downward force to overcome the latch setting and pump open force. At that point, the jar will release and jar downward.
• After impact, pick up the work string to re-engage the mechanical latch, then repeat the jarring cycle as required.