Our Hydraulic / Mechanical drilling jar (HMJ) is well-suited for virtually every drilling condition. Specifically designed to overcome the limitations of purely hydraulic or mechanical drilling jars, the HMJ provides the advantages of both tools in one solution.
Offering a hydraulic delay in the upstroke and acting as a traditional mechanical jar in the down stroke, we engineered the HMJ provide consistent firing regardless of the direction or temperature downhole. Internal mechanical latches allow the jar to be run in tension, neutral, or compression in the drill string. Additionally, these latches hold the jar in place during drilling and tripping operations, eliminating the need for an external safety collar and removing a falling hazard from the rig floor.
Drilling Jars allow an upward or downward jarring action to free stuck drill stem components. A drilling jar installed in the drilling string is immediately available to apply jarring action and release the stuck portion of the drilling string. Drilling Jar is designed for use during drilling operations to apply an intensified force either up or down against a stuck portion of the drilling string. The force or over pull required to free a stuck drill string must be applied in addition to the load already supported by the drilling rig and the drill pipe. This combination force often exceeds the safe tensile strength of the drill pipe, and sometimes the hoisting capacity of the drilling rig. This usually results in a costly and time consuming fishing operation. The jarring force is therefore easily controlled and damage to the hoisting equipment is prevented.
Dependable Design: Hydraulic upstroke with a mechanical down stroke. Continuous, consistent performance: Modified fluid shearing technology from the aerospace industry provides reliable firing. Improved safety on the rig floor: The internal mechanical latch prevents unexpected jarring when making connections or drilling, and eliminates the need for an external safety collar. Versatility: Jar placement can be in tension, neutral, or compression.To jar down, the drill string is lowered until the compressive force applied to the jar exceeds the preset mechanical latch setting. The latch releases allowing the mandrel to accelerate to the fully closed position creating a downward jarring impact. Raising the drill string until free movement stops indicates the latch has reset. The jar is ready for another jarring cycle or to resume normal drilling operations.
To jar up, tension is applied to the jar stretching the drill string. When the jar releases, the energy stored in the stretched drill string accelerates the jar mandrel rapidly to its fully extended position. The sudden stop of the jar mandrel converts the kinetic energy of the moving mass of the drill collars into and intense impact or jarring force. This impact force will vary depending on the actual operating conditions, but can reach eight times the initial over pull.
All Drilling Jars (with the exception of the slim hole 3-1/2 O. D. and smaller) feature our mechanical safety latch mechanism. The mechanical latch firmly holds the mandrel in the neutral position in relation to the jar body, presenting any unaccepted jarring while making connections, tripping in or out of hole, or when tagging bottom and prevents jar movement during normal drilling operations, eliminating unnecessary wear of internal components. The latch is preset to release when either a tension or compressive force is applied to the jar which exceeds the forces seen during normal drilling operations.
The latch release settings can be adjusted at the service facility to expand the range of the jar placement possibilities within the drill string. The latch mechanism allows the jar to run in the drilling string in tension or compression or at the neutral point within the range of the preset release settings.
