PRODUCTS

DJ6 HYDRA-MECHANICAL JAR [ Overview ] [ Operating Instructions ] [ Specifications ] [ Brochures ]

DJ-6 Operating Instructions:

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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* pressure drop across bit)

Once this pull force is exceeded and applied to the jar it will unlatch and begin the metering sequence. At this time the jar can be pulled harder or lighter to increase or decrease 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 travel freely until the jar closes, creating a downward blow.

Raising the drill string until free movement stops will indicate that the Mechanical latch is reset. The jar is then ready to be fired once again in either direction.

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.


For maximum pre-firing pull, see the DJ6 specifications table.

Once the jar has pulled through the mechanical latch, and the metering of the jar has been completed, then the jar will fire, the procedure can be repeated by lowering the drill string, relatching the jar and repeating the sequence.