A drilling tool has an upstream drilling string, a downstream drilling bit, and a percussive device connected between the upstream drilling string and the downstream drilling bit. In a first state, the upstream drilling string is generated with elastic compression by the percussive device, and in a second state, the upstream drilling string releases the elastic compression to apply impacts on the downstream drilling bit through the percussive device. The drilling tool has a prolonged service life and can effectively reduce the drilling cost.

A drilling tool has an upstream drilling string, a downstream drilling bit, and a percussive device connected between the upstream drilling string and the downstream drilling bit. In a first state, the upstream drilling string is generated with elastic compression by the percussive device, and in a second state, the upstream drilling string releases the elastic compression to apply impacts on the downstream drilling bit through the percussive device. The drilling tool has a prolonged service life and can effectively reduce the drilling cost.

A drilling system includes a multi-function sub configured to be coupled to a top drive of a drilling rig and configured to be coupled to a tubular in order to selectively transfer a torque from the top drive to the tubular. The multi-function sub includes a torque sensing component configured to measure the torque provided from the top drive to the tubular via the multi-function sub, a clutch configured to suspend a transfer of torque from the top drive to the tubular when the clutch is released, and a clutch actuator communicatively coupled to the torque sensing component and configured to release the clutch when the torque measured by the torque sensing component is greater than a threshold torque value. The multi-function sub also includes a compensator configured to enable the multi-function sub to move the tubular in an axial direction relative to the top drive.

A drilling system includes a multi-function sub configured to be coupled to a top drive of a drilling rig and configured to be coupled to a tubular in order to selectively transfer a torque from the top drive to the tubular. The multi-function sub includes a torque sensing component configured to measure the torque provided from the top drive to the tubular via the multi-function sub, a clutch configured to suspend a transfer of torque from the top drive to the tubular when the clutch is released, and a clutch actuator communicatively coupled to the torque sensing component and configured to release the clutch when the torque measured by the torque sensing component is greater than a threshold torque value. The multi-function sub also includes a compensator configured to enable the multi-function sub to move the tubular in an axial direction relative to the top drive.

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.

Design parameters for PDC drill bit are correlated to instances of backward whirl, where backward whirl is detected along a lateral axis in the frequency domain during downhole drilling. Two regimes of backward whirl are described and detected cutting-induced backward whirl and friction-induced backward whirl where each regime has different characteristic frequencies, detection methods, and mitigation guidelines. Design parameters are quantified by gauge fullness, drilling efficiency (DE), and whirl index (WI). Design guidelines to mitigate backward whirl are generated by correlating design parameter quantifiers and instances of backward whirl, including both cutting-induced backward whirl and friction-induced backward whirl. Potential drill bit designs are then validated against the generated guidelines in order to mitigate backward whirl in future drilling runs.

Design parameters for PDC drill bit are correlated to instances of backward whirl, where backward whirl is detected along a lateral axis in the frequency domain during downhole drilling. Two regimes of backward whirl are described and detected cutting-induced backward whirl and friction-induced backward whirl where each regime has different characteristic frequencies, detection methods, and mitigation guidelines. Design parameters are quantified by gauge fullness, drilling efficiency (DE), and whirl index (WI). Design guidelines to mitigate backward whirl are generated by correlating design parameter quantifiers and instances of backward whirl, including both cutting-induced backward whirl and friction-induced backward whirl. Potential drill bit designs are then validated against the generated guidelines in order to mitigate backward whirl in future drilling runs.

The disclosure provides an electric drill comprising: a housing; a motor for driving the electric drill to work; an output assembly for outputting the power of the motor; a first brake assembly including a driving disc and a driven disc respectively arranged on the transmission shaft and the output shaft, the driving disc being meshed with the driven disc to transmit power in a non-braking state, and the driving disc and the driven disc being displaced in the axial direction to be separated from each other in a braking state to stop transmitting power; and a second brake assembly including a mass block and a micro switch connected with the motor, and in a braking state, the mass block displacing and triggering the micro switch to stop the motor.

An axial linkage acting between the main body and the gripping assembly of a tool for gripping tubular workpieces includes a drive cam body that coaxially engages an intermediate cam body via a drive thread, with the intermediate cam body coaxially engaging a driven cam body via a driven thread, and with the drive thread and the driven thread having opposite orientations. The linkage includes a latch mechanism for preventing relative axial displacement of the drive cam body and the driven cam body. In operation while unlatched, the linkage converts bi-directional relative rotation into relative axial movement of the drive cam body and the driven cam body, thus increasing or decreasing the overall length of the linkage according to the rotational direction. The linkage can be re-latched using any of multiple operational sequences.

An axial linkage acting between the main body and the gripping assembly of a tool for gripping tubular workpieces includes a drive cam body that coaxially engages an intermediate cam body via a drive thread, with the intermediate cam body coaxially engaging a driven cam body via a driven thread, and with the drive thread and the driven thread having opposite orientations. The linkage includes a latch mechanism for preventing relative axial displacement of the drive cam body and the driven cam body. In operation while unlatched, the linkage converts bi-directional relative rotation into relative axial movement of the drive cam body and the driven cam body, thus increasing or decreasing the overall length of the linkage according to the rotational direction. The linkage can be re-latched using any of multiple operational sequences.