• Griffith Shock Tool

    Description

    The Griffith Shock Tool is designed to isolate the drill string from axial deflections produced by the bit during drilling operations. This reduces impact on the bit and drill string and increases penetration rates by keeping the bit on bottom during rough drilling conditions.

    Constant load/deflection characteristics are maintained regardless of hole depth, bit weight, pump pressure, mud weight or torque. Free vertical movement is assured by guiding the mandrel in the barrel above and below the spline drive to prevent lateral loads from acting on the drive assembly. Griffith Shock Tools are sprung in both directions to compensate for pump open forces.

    The Griffith Shock Tool contains a chamber and piston to compensate for lubricant expansion at higher operating temperatures.

    Larger diameter (11" to 14") tools are designed with a pressure compensation system to reduce the excessive pump open effect inherent in larger diameter tools. This design permits a relatively low spring rate, desirable when drilling large diameter holes, without fully extending the tool at high pump pressure. 14" Shock Tools are available with an optional reamer sub for 17-1/2" hole size.

    Griffith Shock Tools are available with a standard seal kit rated to 200°F or an optional higher temperature seal kit rated at 350°F.

    "Hot Hole" Applications:

    National Oilwell Varco also manufactures shock tools designed for "hot hole" applications with seals rated above 350°F. The design and features of the "hot hole" tools are similar to the standard tools with the exception of the sealing system required for the high temperature application.

    Small Diameter Hydraulic Shock Tools:

    National Oilwell Varco manufactures small diameter, single-acting hydraulic shock tools in 3-1/8" (series 4407) and 3-3/8" (series 4405) sizes. Typical applications include coiled tubing drilling. Like the larger diameter sizes, these tools dampen induced vibrations and increase ROP during drilling operations.

    How to Order

    Specify:

    • Outer Diameter
    • Connections
    • Bottom hole temperature

    Features/Benefits

    Features:

    • Will not build angle, as it is well stabilized between barrel and mandrel
    • Reduces bit bounce and extends bit life by reducing impact loads on teeth and bearings
    • Reduces shock and vibration induced drill string failures
    • Reduces damage to surface equipment
    • Unaffected by hydrostatic pressure

    Benefits:

    • Absorbs axial vibration in both directions
    • Increases rate of penetration
    • Reduces impact on the drill bit
    • Protects sensitive downhole electronics
    • Reduces vibration induced drillstring failures