PRODUCTS

DJ10 DOUBLE ACTING HYDRAULIC/MECHANICAL JAR [ Overview ] [ Operating Instructions] [ Specifications ] [ Brochures ]

DJ10 Double Acting Hydraulic/Mechanical Operating Instructions


The operation of the DJ10 is similar to the Cougar DJ6 Hydraulic Jar but the DJ10 Two Way Hydraulic Jar requires slightly modifying the jarring procedure.

JARRING UP

In order to fire the jar upwards, the operator must determine the force or pull required to unlatch the jar to begin the metering of the jar.

Formula: Pulling force = lock setting + buoyed drill string weight above the jar + hole drag - pump open force. (pump open force = washpipe area multiplied by the pressure drop across bit)

Once this pull force is exceeded and applied to the jar, it will unlatch and begin the metering sequence. During metering the jar can be pulled more or less to increase or decrease the jarring impact. The force or pull used will determine the delay time of the jar until impact.”

 

JARRING DOWN

To fire the jar down, the drill string is lowered applying weight to the latch exceeding the preset mechanical latch setting. At that point, the latch will release allowing the jar to meter downwards until the jar fires, creating a downward blow.

Formula: Pushing force = lock setting  + pump open force + hole drag.

Once the latch is released, push down no higher than the maximum alllowable push for firing.  If the jar is required to fire again, lift and reset the jar to repeat the process. To return to drilling, lift up until off bottom again, and then go back to drilling.

OPERATING NOTES

Drill collars will assist the performance of the jars enhancing their performance and increasing impact.

The harder the jar is pulled, the greater the impact, the softer they are pulled the softer impact, (Maximum pre-firing up information is provided in this brochure).

It is recommended to run the jars in the lower section of the drill collars if possible.

It is recommended not to run the jars in the neutral point.