A telescopic tool is located intermediate a conveyance string and permits an uphole portion to be manipulated through reciprocation and rotation regardless of the fixed nature of a downhole portion. In embodiments, tools uphole of telescopic joint can be actuated by casing manipulation to aid in placement of cement. In other embodiments, such as during running into the wellbore, the tool can be selectively actuated to cause the uphole casing string to lock to, and rotate, the casing string located downhole.

Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole string comprising a disintegration device and a damping system at least one of in and on the downhole string, the damping system configured to damp torsional oscillations of the downhole string. The methods include installing a damping system at least one of on and in the downhole system with the downhole system including a downhole string having a disintegration device and the damping system is configured to damp torsional oscillation of the downhole string.

A regulating device is for use in a drill string between a drilling machine and a drill bit. The regulating device has a tubular female portion which at least partly encloses a tubular male portion; a helical coupling between the female portion and the male portion to allow a telescoping movement of the regulating device in both directions between a fully extended position and a fully retracted position, the movement of the regulating device occurring when there is a difference in rotational speed between the female portion and the male portion; a first biasing device which is arranged to exert a driving force to drive the regulating device towards its extended position; and a second biasing device.

The invention relates to a downhole assembly to mitigate high frequency torsional oscillation, in particular the high frequency torsional oscillation which can occur in a drilling operation for geothermal energy or for oil and gas. The downhole assembly (10) has a rotary steerable tool (18) and a high frequency torsional oscillation mitigation tool (20), the high frequency torsional oscillation mitigation tool having a one-way coupling (100), the high frequency torsional oscillation mitigation tool being located above the rotary steerable tool. The invention also relates to an oscillation mitigation tool (20) suitable for use in a downhole assembly. The high frequency torsional oscillation mitigation tool has a first end, a second end, and a one-way coupling (100) between the first end and the second end. The tool has a first connector (142) at the first end and a second connector (144) at the second end, the first and second connectors being configured for releasable connection to other downhole components in use. The one-way coupling has a first part (134) and a second part (140), the first part being connected to rotate with the first end and the second part being connected to rotate with the second end. The one-way coupling has an engaged condition in which the first part (142) and the second part (144) can rotate together whereby drill string rotation can be communicated to the drill bit. The one-way coupling has a disengaged condition in which the first part can rotate relative to the second part.

The invention relates to a drill rod for transferring a torque comprising an elongate rod base body, along which runs at least one base line for a fluid and/or electric current and/or data, an upper suspension device for suspending the drill rod from a support element, a rotary bearing, which is arranged between the suspension device and the rod base body, wherein the rod base body is mounted rotatably relative to the suspension device about a rod longitudinal axis, and a rotary feedthrough, through which a line connection is formed between at least one feed line, which is fixed relative to the support element, and the at least one base line of the rotatably-mounted rod base body. The invention is characterized here in that the rotary bearing is arranged axially distanced from the rotary feedthrough, and in that the rotary bearing comprises an axial bearing which is arranged above or below the rotary feedthrough. The invention furthermore relates to a drilling apparatus comprising such a drill rod and to a method for retrofitting an existing Kelly bar arrangement.

A vibration damping device for use with downhole electronics may comprise: a device housing mechanically coupled to the downhole electronics and defining a receptacle; and an inertia element movably supported in the receptacle; wherein the volume of the receptacle is greater than the volume of the inertia element so as to define an interstitial volume therebetween and wherein the interstitial volume is occupied by a fluid or an elastomer. A method for tuning a downhole torsional damping device to match a desired downhole electronics may comprise a) calculating a set of natural frequencies and mode shapes for the downhole electronics, b) selecting a desired frequency from the calculated natural frequencies, c) tuning the damping device characteristics to match the selected frequency, d) using the mode shapes to place the damping device. The mode shapes may include antinodes and step d) includes positioning a damping device at an antinode.

An actuator of a downhole tool used in oil and gas exploration and production operations is operable to actuate a first implement in a first direction. A biasing device of the downhole tool is operable to actuate the first implement in a second direction, opposite the first direction. A dampener of the downhole tool is operable to slow an actuation speed of the first implement in the first direction, the second direction, or both. Actuating the first implement in the first direction also actuates a second implement of a flow control device (FCD) of the downhole tool, to which the first implement is connected, in the first direction, placing the FCD in a first (e.g., open) configuration. Actuating the first implement in the second direction also actuates the second implement of the FCD in the second direction, placing the FCD in a second (e.g., closed) configuration.

A dampener device configured for incorporation into a downhole tool in a drilling system for absorbing axial, lateral and torsional shocks and vibrations to protect instrumentation during a drilling process includes a main sleeve having a main cavity containing a main spring and a first elastomeric ribbon interleaved between coils of the main spring. An adapter is connected to or formed monolithically relative to the main sleeve. The adapter is configured for connection to a first tool component. A plunger is configured to compress the main spring and a connector is configured for connection to a second tool component. The connector is attached to or formed monolithically relative to the plunger. A shaft extends between the adapter and the connector. The shaft is provided with an anti-rotation structure.

A downhole shock absorbing sub which includes a tubular main stem extending through a sub housing and a lateral shock absorbing assembly positioned within the sub housing. The lateral shock absorbing assembly includes an activator ring positioned around the main stem, the activator ring including a plurality of wedge inserts positioned around a perimeter of the activator ring. A reaction collar is positioned on each side of the activator ring with the reaction collars including ramp surfaces engaged by the wedge inserts. A spring system is positioned to resist movement of the reaction collars away from the activator ring, whereby lateral movement of the main stem causes the wedge inserts to move the reaction collars against the spring system.

A downhole tool (30) particularly for controlling torque and torsion and also for absorbing/dampening vibration in a downhole string is provided and comprises an inner mandrel (1, 7, 11, 15) and an outer mandrel (14, 13, 12, 19) and a coupling mechanism (8) to couple the inner and the outer mandrel, the coupling mechanism comprising one or more longitudinally elongate members (8) acting between the inner and outer mandrel, wherein the one or more longitudinally elongate members are substantially fixed in their longitudinal length but substantially do not resist relative compressive longitudinal movement occurring between the inner and outer mandrels. The coupling mechanism is arranged such that compression of the inner and outer mandrels results in compression of the one or more longitudinally elongate members without necessarily resulting in relative rotation of the inner and outer mandrels.