A method of rotating a drill string driven by a drive system using a control system implemented by a controller or a filter includes generating a mathematical energy model of the drive system, the drill string, and the controller, wherein the mathematical energy model comprises at least one or more first energy values of the drive system and one or more second energy values of the drill string, determining the one or more first energy values of the drive system and the one or more second energy values of the drill string, measuring one or more vibration values torsional vibrations at the drive system with a sensor, determining an updated proportional gain and an updated integral gain of the controller or the filter based on at least the one or more first energy values of the drive system, the one or more second energy values of the drill string, and the one or more vibration values, providing an output signal representing the updated proportional gain and the updated integral gain to the controller or the filter, and controlling rotation of a quill of the drive system based on the output signal.

A method of rotating a drill string driven by a drive system using a control system implemented by a controller or a filter includes generating a mathematical energy model of the drive system, the drill string, and the controller, wherein the mathematical energy model comprises at least one or more first energy values of the drive system and one or more second energy values of the drill string, determining the one or more first energy values of the drive system and the one or more second energy values of the drill string, measuring one or more vibration values torsional vibrations at the drive system with a sensor, determining an updated proportional gain and an updated integral gain of the controller or the filter based on at least the one or more first energy values of the drive system, the one or more second energy values of the drill string, and the one or more vibration values, providing an output signal representing the updated proportional gain and the updated integral gain to the controller or the filter, and controlling rotation of a quill of the drive system based on the output signal.

Shock absorber systems include a drive plate having a plurality of removable lugs. The drive plate is connectable to a rotary drive shaft. The shock absorber further includes a driven plate connectable to a rotary driven shaft. A housing may be fixedly secured to either or both of the drive plate and the driven plate. The housing may have an outer wall forming a hollow center portion and a plurality of openings extending through the outer wall to the hollow center portion. Each opening of the plurality of openings may have first and second positive stops formed thereon. The shock absorber further comprises an elastomeric member disposed in the housing between the drive plate and the driven plate. The elastomeric member is configured to absorb vibration from the driven plate. Each removable lug of the plurality of removable lugs has first and second striking faces at a radially distal edge and on circumferentially opposing sides.

Shock absorber systems include a drive plate having a plurality of removable lugs. The drive plate is connectable to a rotary drive shaft. The shock absorber further includes a driven plate connectable to a rotary driven shaft. A housing may be fixedly secured to either or both of the drive plate and the driven plate. The housing may have an outer wall forming a hollow center portion and a plurality of openings extending through the outer wall to the hollow center portion. Each opening of the plurality of openings may have first and second positive stops formed thereon. The shock absorber further comprises an elastomeric member disposed in the housing between the drive plate and the driven plate. The elastomeric member is configured to absorb vibration from the driven plate. Each removable lug of the plurality of removable lugs has first and second striking faces at a radially distal edge and on circumferentially opposing sides.

Disclosed is a torque limiter having driver mandrel and driven axially aligned mandrels, a piston movable into and out of an engaged position wherein the driver and driven mandrels are coupled together to transmit torque there between. Hydraulically locking the movable piston in an engaged position. Disengaging the hydraulic lock when during rotation when a specified torque magnitude is exceeded to allow relative rotation between the mandrels. Resetting the torque limiter by hydraulically locking the piston in the engaging position when relative rotation ceases or is reduced.

Disclosed is a torque limiter having driver mandrel and driven axially aligned mandrels, a piston movable into and out of an engaged position wherein the driver and driven mandrels are coupled together to transmit torque there between. Hydraulically locking the movable piston in an engaged position. Disengaging the hydraulic lock when during rotation when a specified torque magnitude is exceeded to allow relative rotation between the mandrels. Resetting the torque limiter by hydraulically locking the piston in the engaging position when relative rotation ceases or is reduced.

The invention relates to a downhole tool for use in a petroleum well. The downhole tool (100) comprises a first part (110) comprising a driving unit (8), and second part (120) comprising a driven unit (9), wherein the drive unit (8) is configured for driving the driven unit (9). The downhole tool (100) comprises a coupling unit (1) having an input side (S1) coupled with the driving unit (8) and an output side (S2) coupled with the driven unit (9), wherein the driving unit (8) is configured for driving the driving unit (9) via the coupling unit (1) comprising a torque limiting coupling having a first operational mode, the coupling unit (1) transfers all torque from the input side (S1) to the output side (S2), the coupling unit (1) further having a second operational mode, wherein the coupling unit (1) slips such that less torque is transferred form the input side (S1) to the output side (S2), wherein the second operational mode is automatically activated when the torque load on the input side exceeds a predefined level, and wherein the first operational mode is automatically activated when the torque load on the input side reduces to a level below a further predefined level. The coupling unit (1) comprises a displacement pump (2), wherein the displacement pump (2) is activated by opening of a pressure-limitation valve (4), for facilitating slipping of the coupling unit (1) when the coupling unit (1) is switching to the second operational mode, and wherein the displacement pump (2) is deactivated by closing of the pressure-limitation valve (4), for locking the coupling unit (1) when the coupling unit (1) is switching to the first operational mode.

A drilling rig apparatus is disclosed for mitigating stick-slip using a saver sub that is compatible with different top drives. The saver sub includes a smart material adjustable whenever a stand is added to the drill string to have different spring characteristics to generally match the impedance of the top drive to the impedance of the drill string. The saver sub also includes a magneto rheological fluid that is adjusted whenever a stand is added to the drill string to compensate for the changed characteristics of the drill string. The damping constant implemented by the MR fluid enables the saver sub to absorb stick-slip vibrations at the top drive. Each time that a stand is connected to the drill string, the spring and damping constants may be updated to accommodate the changing characteristics of the drill string.

A drilling rig apparatus is disclosed for mitigating stick-slip using a saver sub that is compatible with different top drives. The saver sub includes a smart material adjustable whenever a stand is added to the drill string to have different spring characteristics to generally match the impedance of the top drive to the impedance of the drill string. The saver sub also includes a magneto rheological fluid that is adjusted whenever a stand is added to the drill string to compensate for the changed characteristics of the drill string. The damping constant implemented by the MR fluid enables the saver sub to absorb stick-slip vibrations at the top drive. Each time that a stand is connected to the drill string, the spring and damping constants may be updated to accommodate the changing characteristics of the drill string.

The present disclosure is directed to systems and methods for rotating a drill string to mitigate stick-slip oscillations. An embodiment includes a method of rotating a drill string driven by a drive system using a control system. The method includes measuring torque values of the drive system with a torque sensor. The method also includes determining a frequency of stick-slip oscillations at the drive system based on the torque values using the control system. The method also includes determining an estimated instantaneous rotational speed of the drive system with the control system based on at least the frequency of stick-slip oscillations and a characteristic impedance of the drill string. The method also includes adjusting the estimated instantaneous rotational speed based on changes in the torque values to define an adjusted estimated instantaneous rotation speed with the control system. The method also includes providing an output signal representing the adjusted estimated instantaneous rotational speed to the drive system. The method also includes controlling rotation of a quill of the drive system based on the output signal.