Abstract: The disclosed embodiments include energy harvesting devices, methods to operate the energy harvesting devices, and downhole power generating systems. In one embodiment, an energy harvesting device includes an outer stator having a first cavity formed therein. The energy harvesting device further includes a rotor disposed within the first cavity, the rotor including a second cavity, at least one radial slot, and a helical slot extending from a first end of the rotor towards a second end of the rotor. The energy harvesting device further includes an inner stator disposed within the second cavity. The energy harvesting device further includes an armature adjacent to the rotor, the armature coupled to at least one winding coupled to an electrical component to provide an electrical current to power the electrical component. The energy harvesting device further includes a housing coupled to the outer stator.

Abstract: The disclosed embodiments include energy harvesting devices, methods to operate the energy harvesting devices, and downhole power generating systems. In one embodiment, an energy harvesting device includes an outer stator having a first cavity formed therein. The energy harvesting device further includes a rotor disposed within the first cavity, the rotor including a second cavity, at least one radial slot, and a helical slot extending from a first end of the rotor towards a second end of the rotor. The energy harvesting device further includes an inner stator disposed within the second cavity. The energy harvesting device further includes an armature adjacent to the rotor, the armature coupled to at least one winding coupled to an electrical component to provide an electrical current to power the electrical component. The energy harvesting device further includes a housing coupled to the outer stator.

Abstract: A bent sub for use in a bottom hole assembly, between the power section of a mud motor and the drill bit, which can have its bend angle altered from the surface while remaining downhole, and a method for adjusting the bend of a bent sub. A biasing mechanism includes a number of linear actuators radially positioned about the tool centerline and oriented for axial motion. The linear actuators are connected to travelling blocks, which engage the upper end of the inner race a pivoting bearing assembly. The lower end of the inner race is connected to the mud motor bearing assembly. The linear actuators and can be actuated in coordination to tilt the inner race, and hence, the mud motor bearing assembly, to various selectable angles in any radial direction for control of tool face. In an embodiment, the actuators are battery-powered motor-driven lead screws.

Abstract: A drill string stabilizer has an elongated cavity formed in an exterior surface of the body. An elongated blade is generally disposed to extend from the cavity. The blade is extended or retracted by rotating a stud threaded on opposite ends with left and right handed threads. Rotation of the stud causes axial movement of slide blocks threadingly engaged to the stud. A follower and track between the body and the slide blocks causes the slide blocks to slidingly engage the body. The blade track is inclined relative to the body track so that the blade radially retracts or extends relative to the body as blocks are moved along their respective tracks by rotation of the stud. The position of each stabilizer blade is independent of the other blades.

Abstract: In one example, a nutating fluid-mechanical energy converter to power wellbore drilling includes a fluid-mechanical device and a rotation transfer device, each positionable in a wellbore drill string. The fluid-mechanical device includes a stator including an outer cylinder having a longitudinal passage and a longitudinal guide positioned in the longitudinal passage, which, with the stator, defines an annulus. A rotor cylinder is positioned in the annulus. The rotor cylinder includes a sidewall with a guide opening to receive the longitudinal guide. The rotor cylinder rotates within the stator along the longitudinal guide in response to the wellbore drilling fluid flow through the annulus. The rotation transfer device transfers at least a portion of a rotation of the rotor cylinder to a wellbore drill bit.

Abstract: A shock tool for a drill string includes an outer tubular housing having female multi-spiral helical spline grooves disposed on an interior surface of the housing, and an inner tubular mandrel having a portion of an exterior circumferential surface with mating male multi-spiral helical splines. The inner tubular mandrel is telescopically and rotationally received in the outer tubular housing with the male splines received in the female spline grooves of the housing.

Abstract: A drill string stabilizer has an elongated cavity formed in an exterior surface of the body. An elongated blade is generally disposed to extend from the cavity. The blade is extended or retracted by rotating a stud threaded on opposite ends with left and right handed threads. Rotation of the stud causes axial movement of slide blocks threadingly engaged to the stud. A follower and track between the body and the slide blocks causes the slide blocks to slidingly engage the body. The blade track is inclined relative to the body track so that the blade radially retracts or extends relative to the body as blocks are moved along their respective tracks by rotation of the stud. The position of each stabilizer blade is independent of the other blades.

Abstract: A shock tool for a drill string includes an outer tubular housing having female multi-spiral helical spline grooves disposed on an interior surface of the housing, and an inner tubular mandrel having a portion of an exterior circumferential surface with mating male multi-spiral helical splines. The inner tubular mandrel is telescopically and rotationally received in the outer tubular housing with the male splines received in the female spline grooves of the housing.

Abstract: In one example, a nutating fluid-mechanical energy converter to power wellbore drilling includes a fluid-mechanical device and a rotation transfer device, each positionable in a wellbore drill string. The fluid-mechanical device includes a stator including an outer cylinder having a longitudinal passage and a longitudinal guide positioned in the longitudinal passage, which, with the stator, defines an annulus. A rotor cylinder is positioned in the annulus. The rotor cylinder includes a sidewall with a guide opening to receive the longitudinal guide. The rotor cylinder rotates within the stator along the longitudinal guide in response to the wellbore drilling fluid flow through the annulus. The rotation transfer device transfers at least a portion of a rotation of the rotor cylinder to a wellbore drill bit.

Abstract: A bent sub for use in a bottom hole assembly, between the power section of a mud motor and the drill bit, which can have its bend angle altered from the surface while remaining downhole, and a method for adjusting the bend of a bent sub. A biasing mechanism includes a number of linear actuators radially positioned about the tool centerline and oriented for axial motion. The linear actuators are connected to travelling blocks, which engage the upper end of the inner race a pivoting bearing assembly. The lower end of the inner race is connected to the mud motor bearing assembly. The linear actuators and can be actuated in coordination to tilt the inner race, and hence, the mud motor bearing assembly, to various selectable angles in any radial direction for control of tool face. In an embodiment, the actuators are battery-powered motor-driven lead screws.

Abstract: One example of a nutating fluid-mechanical energy converter includes a stator and a rotor. The stator includes an outer cylinder having a longitudinal passage 101 and an inner guide cylinder disposed longitudinally within the outer cylinder. The inner guide cylinder and outer cylinder are concentric and define an annulus for fluid flow. A longitudinal guide is attached to an outer surface of the inner guide cylinder and extending outwardly toward an inner surface of the outer cylinder. The rotor is positioned in the annulus to be eccentric relative to the outer cylinder. The rotor has a sidewall with a guide opening to receive the longitudinal guide. Fluid flowing through the annulus imparts a torque on the rotor causing the rotor to nutate within the annulus. The nutational motion of the rotor can be converted into a rotational motion using a suitable rotary output device.

Abstract: One example of a nutating fluid-mechanical energy converter includes a stator and a rotor. The stator includes an outer cylinder having a longitudinal passage 101 and an inner guide cylinder disposed longitudinally within the outer cylinder. The inner guide cylinder and outer cylinder are concentric and define an annulus for fluid flow. A longitudinal guide is attached to an outer surface of the inner guide cylinder and extending outwardly toward an inner surface of the outer cylinder. The rotor is positioned in the annulus to be eccentric relative to the outer cylinder. The rotor has a sidewall with a guide opening to receive the longitudinal guide. Fluid flowing through the annulus imparts a torque on the rotor causing the rotor to nutate within the annulus. The nutational motion of the rotor can be converted into a rotational motion using a suitable rotary output device.