Bearing assemblies and bearing apparatuses are disclosed. In an embodiment, a first bearing assembly includes tilting pads and a first plurality of sliding superhard bearing elements secured to a first support ring. In an embodiment, a second bearing assembly includes a substantially continuous bearing element secured to a second support ring. In an embodiment, a bearing apparatus includes the first bearing assembly and the second bearing assembly, with the substantially continuous bearing element generally facing the tilting pads. At relatively low rotational speeds, the first plurality of superhard bearing elements supports at least a portion of a load exerted on the bearing assembly. At relatively high rotational speeds, the tilting pads support at least a majority of the load.

Embodiments of the invention are directed to bearing assemblies configured to effectively provide heat dissipation for bearing elements, bearing apparatuses including such bearing assemblies, and methods of operating such bearing assemblies and apparatuses. In an embodiment, a bearing assembly includes a plurality of superhard bearing elements distributed about an axis. Each superhard bearing element of the plurality of superhard bearing elements has a superhard table including a superhard surface. The bearing assembly includes a support ring structure coupled to the plurality of superhard bearing elements. One or more of the superhard bearing elements includes a superhard table, which may improve heat transfer from such superhard bearing elements.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A drill string steering system includes a motor and a rotary valve body disposed in a tool body. The motor includes a motor shaft coupled to the motor and extending within a central bore of the tool body. The motor shaft has a downhole engagement portion that includes a first splined surface. The rotary valve body includes a disk-shaped component and a valve shaft coupled to the disk-shaped component and extending uphole of the disk-shaped component. The valve shaft includes a second splined surface engageable with the first splined surface for rotation of the motor shaft to be imparted to the rotary valve body.

Various embodiments relate to a bearing assembly including a support ring configured to reduce thermal warping under operational temperature conditions, a bearing apparatus that may utilize such a thrust-bearing assembly, and applications that incorporate the disclosed bearing apparatuses such as downhole motors in subterranean drilling systems, directional drilling systems, and many other apparatuses. In an embodiment, a bearing assembly includes a plurality of superhard bearing elements distributed circumferentially about an axis. The thrust-bearing assembly further includes a support ring having the plurality of superhard bearing elements mounted thereto. The support ring includes at least one thermal-warping-reducing feature configured to reduce a radial moment, compared to if the at least one thermal-warping-reducing feature were absent from the support ring, which is thermally induced in the support ring when the support ring and the plurality of superhard bearing elements are exposed to operational temperature conditions.

A wellbore assembly is provided that can include a first motor housing assembly member and a second motor housing assembly member that can bend relative to the first motor housing assembly at a bend location. The assembly can also include a strain gauge positioned on a first side of the bend location to determine an amount of bend of the second motor housing assembly member relative to the first motor housing assembly member by determining a strain. Based on the strain, the amount of bend or bend direction of the second motor housing assembly member relative to the first motor housing assembly member can be determined.

A wellbore assembly is provided that can include a first motor housing assembly member and a second motor housing assembly member that can bend relative to the first motor housing assembly at a bend location. The assembly can also include a strain gauge positioned on a first side of the bend location to determine an amount of bend of the second motor housing assembly member relative to the first motor housing assembly member by determining a strain. Based on the strain, the amount of bend or bend direction of the second motor housing assembly member relative to the first motor housing assembly member can be determined.

Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) and methods of fabricating such PDCs. In an embodiment, a PDC includes a substrate and a preformed polycrystalline diamond table including an interfacial surface bonded to the substrate and an opposing working surface. The preformed polycrystalline diamond table includes a proximal region extending from the interfacial surface to an intermediate location within the preformed polycrystalline diamond table that includes a metallic infiltrant infiltrated from the substrate, and a distal region extending from the working surface to the intermediate location that is substantially free of the metallic infiltrant. A boundary exists between the proximal and distal regions that has a nonplanar irregular profile characteristic of the metallic infiltrant having been infiltrated into the preformed polycrystalline diamond table.

A method of estimating properties of wellbore cement by penetrating the cement, and monitoring the amount of energy or power required for penetrating the cement. Penetrators include a drill bit that bores into the cement, and probes or pins that are forced into the cement. The energy or power monitored can be current and/or voltage supplied to a motor that drives the drill bit or probe. Comparing the monitored energy or power with that required to penetrate a reference cement sample of known properties can yield information about the cement being sampled. When the wellbore is lined with multiple coaxially disposed strings of casing with cement between adjacent strings and on the outer surface of the outer string; the method further includes obtaining core samples from portions of each string, each layer of cement, and formation adjacent the wellbore.

Bearing assemblies, apparatuses, and motor assemblies using the same are disclosed. In an embodiment, a bearing assembly may include a plurality of superhard bearing elements distributed circumferentially about an axis. Each of the superhard bearing elements may include a bearing surface. The bearing assembly may also include a support ring structure having a support ring that carries the superhard bearing elements. The support ring structure may include at least one erosion resistant region exhibiting a higher erosion resistance than another region of the support ring.