An apparatus for damping vibrations includes an inertial mass disposed in a cavity in a rotatable downhole component, the rotatable component configured to be disposed in a borehole in a subsurface formation, such as a resource bearing formation, the inertial mass coupled to a surface of the cavity by a damping fluid and configured to move within the cavity relative to the downhole component. The apparatus also includes a damping fluid disposed in the cavity between the inertial mass and an inner surface of the cavity, where rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from rotational acceleration of the rotatable downhole component and causing the rotational acceleration to be reduced.

A vibration isolating coupler for isolating torsional vibration in a drill string includes a first coupler portion including a first annular wall having an external surface and an internal surface defining a first central bore portion and a second coupler portion disposed within the first central bore portion. The second coupler portion includes a second annular wall having an external surface section and an internal surface section defining a second central bore portion, and a plurality of connecting elements extending from the internal surface of the first annular wall through the second annular wall across the second central bore portion and connecting with the internal surface of the second annular wall.

A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.

A shock absorber apparatus includes a rod; a tool connection on a first end of the rod; a piston on a second end of the rod; a flange on the rod between the tool connection and the piston; a ring connection slidably connected to the rod between the tool connection and the flange; a first spring between the ring connection and the flange to bias the ring connection axially away from the flange; a sleeve, connected to a second spring between the second spring and the piston, slidably encircling the piston and a portion of the rod, and extending past the piston to a pumpdown connection; and a fin. A method for a placing a tool in a landing ring of a drilling tubular includes using the shock absorber apparatus to absorb shocks caused by the landing operation.

The present invention discloses a drilling speed improvement device capable of producing both hydraulic pulse and impact vibration. The device has a pressure transfer rod that is arranged at an upper end of a lower joint. A spring chamber is formed among a drill body, the pressure transfer rod and the lower joint. A spring is arranged in the spring chamber. A communicating hole is formed in the drill body. A piston is arranged at an upper end of the pressure transfer rod. A pressure bearing head is arranged at an upper end of the piston. A pressure bearing base is arranged on the inner side of an upper joint. Drill bit impact loads and drilling fluid pulse jets are modulated by the longitudinal vibration energy of a drill stem, the rock breaking efficiency of a drill bit is improved by both dynamic and static loads, and harm caused by vibration of the drill stem is reduced.

A down-the-hole hammer drill bit retaining assembly is arranged to releasably retain a drill bit at a hammer arrangement of a percussion drilling apparatus. The retaining assembly includes a drive sub and a retainer ring. The drive sub has at least one indent to provide a fluid communication pathway for a flushing fluid extending over a radially outward facing surface of the retainer ring and into an internal region of the drive sub in contact with inwardly projecting splines.

An interference apparatus is provided for a motor shaft transmission assembly. The interference apparatus may include split-ring shells and a retaining device. The interference apparatus may be mounted to an intermediate sleeve of the motor shaft transmission assembly. The interference apparatus is configured to prevent the loss of certain motor shaft transmission assembly components downhole in the event of a failure of the motor transmission due to dynamic loads.

The present invention discloses a drilling speed improvement device capable of producing both hydraulic pulse and impact vibration. The device has a pressure transfer rod that is arranged at an upper end of a lower joint. A spring chamber is formed among a drill body, the pressure transfer rod and the lower joint. A spring is arranged in the spring chamber. A communicating hole is formed in the drill body. A piston is arranged at an upper end of the pressure transfer rod. A pressure bearing head is arranged at an upper end of the piston. A pressure bearing base is arranged on the inner side of an upper joint. Drill bit impact loads and drilling fluid pulse jets are modulated by the longitudinal vibration energy of a drill stem, the rock breaking efficiency of a drill bit is improved by both dynamic and static loads, and harm caused by vibration of the drill stem is reduced.

Methods and systems for damping torsional oscillations of downhole systems are described. The systems include a downhole string, a bit support assembly configured to support and receive a disintegration device, wherein the disintegration device is disposed on an end of the downhole string and mounted to the bit support assembly, and a damping system configured at least one of on and in the bit support assembly, the damping system comprising at least one damper element arranged in contact with a portion of the bit support assembly.

A downhole regulating device used in a downhole drill string between a drilling rig and a drill bit. The downhole regulating device has a helical coupling between the upper and lower portion to allow a relative axial and rotational movement defined by the lead of the helical coupling, between the upper and lower portions; a bi-directional biasing device that resists movement in both extension and contraction from the neutral position depending on the combination of pumping pressure, torque, axial hanging loads from drill string components below the tool and applied weight on bit. The biasing device is designed such that there is no pre-load required. A secondary one-directional element may be part of the biasing device to modify the spring rate or stroke length in contraction direction. A metal and composite laminated torsion spring is also described.