A drilling system for drilling a borehole. The drilling system may include a drill string, a drill bit coupled to the drill string, a mud motor coupled to the drill string uphole of the drill bit and operable to rotate the drill bit via a driveshaft, a bearing assembly coupled to a downhole end of the mud motor and operable to support the driveshaft, and a rotary steerable system (“RSS”) operable to push the drill bit in a desired direction via pads extended using drilling fluid flowing through the driveshaft and to the RSS. The bearing assembly may include bearings positioned circumferentially around a bore of the bearing assembly, a fluid flowpath through the bearings to allow drilling fluid to pass through the bearings, and a choke assembly positioned in the fluid flowpath and operable to restrict a flow of the drilling fluid through the fluid flowpath.

A drilling system for drilling a wellbore using drilling fluid includes a drillstring, a drill bit coupled to the drillstring, and a mud motor coupled to the drillstring and operable to rotate the drill bit by rotating a driveshaft with a bore. The drilling system also includes a bearing assembly that includes a bypass fluid flowpath through the bearings for drilling fluid to divert from the bore. A choke assembly positioned in the bypass fluid flowpath restricts flow of the diverted drilling fluid such that some diverted drilling fluid flows into an annulus in the wellbore outside of the bearing assembly through an unsealed annulus port and some of diverted drilling fluid is recaptured through a return flowline. The drilling system also includes a rotary steerable system operable to push the drill bit in a desired direction using pads extendable with the drilling fluid.

An electrical submersible well pump assembly (ESP) has a spring brake having helical turns mounted between the shaft and one of the housings. The spring brake allows free rotation of the shaft in a driving direction and stops the shaft from rotating in a reverse direction. The spring brake may have one end be affixed to the housing to rotate in unison in both directions. Alternately, the spring brake may have one end affixed to the shaft for rotation with the shaft. Further, the spring brake could be free of being connected to either the shaft or the housing. A shear member may be mounted between the shaft and the housing to prevent any rotation of the shaft during run-in.

A reactive torque automatic balancing device for a screw drilling tool includes an upper joint (1); a core cylinder (9) having an inner chamber in communication with the screw drilling tool (305) located downstream, so that drilling fluid from the inner chamber of the upper joint (1) flows to the screw drilling tool (305) through the inner chamber of the core cylinder (9) to allow the screw drilling tool to perform drilling; a lower joint (16) fixedly arranged at a lower end of the core cylinder (9); and an automatic balancing assembly, which is arranged between an outer wall of the core cylinder (9) and an inner wall of the upper joint (1), and driven by hydraulic pressure generated by a part of the drilling fluid flowing through the inner chamber of the upper joint (1).

Bearing assemblies, apparatuses, systems, and methods include bearing assemblies where one of the bearing assemblies may include bearing surfaces defining an at least partially conical surface.

An apparatus for use in a wellbore includes a drill string section, a drive shaft disposed in the drill string section, a bearing assembly connected to the drive shaft, and an alignment assembly connecting the bearing assembly to the drill string section. The alignment assembly has a first alignment member and a second alignment member slidingly engaging one another to allow at least a portion of the bearing assembly to tilt relative to the drill string section. A related method includes the steps of positioning a drive shaft in a drill string section; connecting a bearing assembly to the drive shaft using the alignment assembly, the alignment assembly having a first alignment member and a second alignment member; and allowing at least a portion of the bearing assembly to tilt relative to the drill string section using the alignment assembly by having the first alignment member and the second alignment member slidingly engage one another.

Systems and methods for cold-spraying coatings on rotors in motor assemblies for improving reliability of motor assembly use downhole in wellbores is provided. For example, a motor assembly can include a stator positioned downhole in a wellbore and rotor coupled to the wellbore. The rotor can include a base material and a first coating deposited onto the base material via cold spraying for reducing damage to the rotor. The first coating may include sprayed particles that have a melting point temperature that is higher than a temperature of a gas used in the cold spraying. In some examples, the rotor may include a second coating deposited onto the first coating via cold spraying, high velocity oxygen fuel coating, or high velocity air fuel. The first coating may have a first hardness that is less than a second hardness of the second coating.

The invention relates to a rotary drive arrangement for a drill rod having an outer pipe and an inner rod running at least in sections inside the outer pipe, in particular for double-head and/or overburden drilling, with a first gearbox for driving the inner rod in a rotating manner and a second gearbox for driving the outer pipe in a rotating manner, wherein the first gearbox and the second gearbox are independent of each other. According to the invention provision is made in that the first gearbox and the second gearbox are supported in a common gearbox housing and are surrounded by the same.

Embodiments of the invention relate to bearing apparatuses in which one bearing surface of the bearing apparatus includes diamond, while another bearing surface includes a non-diamond superhard material (e.g., silicon carbide). For example, a bearing apparatus may include a bearing stator assembly and a bearing rotor assembly. The bearing stator assembly and bearing rotor assembly each include a support ring and one or more superhard bearing elements generally opposed to one another. The bearing surface(s) of the rotor or stator may include diamond, while the bearing surface(s) of the other of the rotor or stator do not include diamond. Another bearing apparatus may include both thrust- and radial bearing components. The generally opposed thrust-bearing elements may include diamond, while the generally opposed radial bearing elements may not include diamond, but include a non-diamond superhard material, such as silicon carbide.

A rotary actuator assembly can include a fluid motor with a rotor that displaces with hypocyclic precessional motion within a stator in response to fluid flow through the fluid motor, and a gear reducer section including an input gear that is fixed relative to the rotor and displaces with the hypocyclic precessional motion relative to an output gear. Another rotary actuator assembly can include a fluid motor with a rotor having a central longitudinal axis that rotates about a central longitudinal axis of a stator, and a gear reducer section including an input gear that rotates with the rotor and displaces relative to an output gear, and the input gear having the same central longitudinal axis as the rotor. A well system can include at least two fluid motors, and fluid flow through one fluid motor causes rotation of the other fluid motor in the well.