Abstract: An example downhole apparatus includes a drive shaft with a longitudinal axis, a spherical portion that extends radially from the longitudinal axis, and first and second interfacial surfaces proximate the spherical portion. An outer housing is positioned at least partially around the spherical portion. A radial bearing may be between the spherical portion and the outer housing and coupled to the outer housing. The radial bearing may comprise first and second interfacial surfaces in contact with the respective first and second interfacial surfaces of the drive shaft to transmit or receive torque in corresponding first and second rotational directions. A first axial bearing is coupled to the outer housing and in contact with a first end of the spherical portion to axially secure the drive shaft with respect to the outer housing.

Abstract: According to aspects of the present disclosure, systems and methods for controlling the speed of a fluid-controlled drive mechanism are described herein. An example system may include a housing, a variable flow fluid pathway disposed within the housing, an electromagnet coupled to the housing, a fluid-controlled drive mechanism in fluid communication with the variable flow fluid pathway, and a load-generating assembly coupled to the fluid-controlled drive mechanism. An example method may include altering a variable flow fluid pathway disposed within a housing, wherein the variable flow fluid pathway is in fluid communication with a fluid-controlled drive mechanism, and generating an electrical current through an electromagnet, wherein the electromagnet is coupled to the housing.

Abstract: An example method for control of a drilling assembly includes receiving measurement data from at least one sensor coupled to an element of the drilling assembly positioned in a formation. An operating constraint for at least a portion of the drilling assembly may be determined based, at least in part, on a model of the formation and a set of offset data. A control signal may be generated to alter one or more drilling parameters of the drilling assembly based, at least in part, on the measurement data and the operating constraint. The control signal may be transmitted to a controllable element of the drilling assembly.

Abstract: According to aspects of the present disclosure, systems and methods for controlling the direction of a drilling assembly within a borehole are described herein. An example system may include a housing 201 b (FIG. 2B) and a variable flow fluid pathway 203 (FIG. 2B) within the housing 201b. A fluid-controlled drive mechanism 209 (FIG. 2C) may be in fluid communication with the variable flow fluid pathway 203. Additionally, an offset mandrel 212 may be coupled to an output of the fluid-controlled drive mechanism 209. The offset mandrel 212 may be independently rotatable with respect to the housing 201b. The system may also include a bit shaft 216 pivotably coupled to the housing 201b and coupled to an eccentric receptacle of the offset mandrel 212.

Abstract: A mud pulse telemetry tool is used in a drill string that has a drilling fluid flowing inside. The mud pulse telemetry tool may include a pulser disposed in the drill string and a drive system for driving the pulser. The pulser may include a non-rotating mud pulse stator and a mud pulse rotor disposed proximate to the stator. The drive system may include a turbine stator, a turbine rotor, and a rotatable inertial member magnetically coupled to the turbine rotor. The inertial member may be operatively connected at a first end to the mud pulse rotor. In the mud pulse telemetry tool, rotational energy may be transmitted from the turbine rotor to the rotatable inertial member by a magnetic coupling. The rotatable inertial member may be operatively connected to a supplemental motor that is adapted to supplement rotational energy imparted to the rotatable inertial member by the drive system.

Abstract: A method and system for steering a rotary steerable tool in a borehole. A method includes rotating a deflection sleeve about a steerable shaft. A deflection ramp is aligned to deflect the shaft in a predetermined direction by the rotating. The deflection sleeve is axially displaced along the steerable shaft. The steerable shaft is deflected by the displacing.

Abstract: A mud pulse telemetry tool is used in a drill string that has a drilling fluid flowing inside. The mud pulse telemetry tool may include a pulser disposed in the drill string and a drive system for driving the pulser. The pulser may include a non-rotating mud pulse stator and a mud pulse rotor disposed proximate to the stator. The drive system may include a turbine stator, a turbine rotor, and a rotatable inertial member magnetically coupled to the turbine rotor. The inertial member may be operatively connected at a first end to the mud pulse rotor. In the mud pulse telemetry tool, rotational energy may be transmitted from the turbine rotor to the rotatable inertial member by a magnetic coupling. The rotatable inertial member may be operatively connected to a supplemental motor that is adapted to supplement rotational energy imparted to the rotatable inertial member by the drive system.

Abstract: A well tool can include a well tool housing and a cooling section positioned within the well tool housing, the cooling section including a helical cooling fluid flow path, and the flow path having a reversal of direction proximate an end of the cooling section. Another well tool can include a cooling fluid which flows through the helical flow path toward the end of the cooling section in one direction, and which flows through the helical flow path away from the end of the cooling section in an opposite direction. Another well tool can include the cooling fluid which flows through the helical flow path, and which makes multiple passes longitudinally through the cooling section proximate a heat-sensitive device.