Abstract: A sensor and method for use in measuring a physical characteristic of a fluid in a microfluidic system is provided. A microfluidic chip has a thin deformable membrane that separates a microfluidic channel from a microwave resonator sensor. The membrane is deformable in response to loading from interaction of the membrane with the fluid. Loading may be fluid pressure in the channel, or shear stress or surface stress resulting from interaction of the membrane with the fluid. The deformation of the membrane changes the permittivity in the region proximate the sensor. A change in permittivity causes a change in the electrical parameters of the sensor, thereby allowing for a characteristic of the fluid, such as flow rate, or a biological or chemical characteristic, to be measured. Also, a microwave sensor with improved sensitivity for characterizing a fluid in a microfluidic channel is provided.

Abstract: A constant-velocity joint can have three pieces: a yoke, a first adaptor, and a second adaptor. Grooves on opposite sides of the yoke can receive forks of the adaptors and be perpendicular to one another. The yoke can have a guide surface within each groove so that a matching following surface on the fork of the adaptor can engage the guide surface to guide the movement of the fork within the groove. The adaptors may pivot within the grooves such that surfaces of flanks of the forks remain engaged or provide a consistent amount of surface contact with flanks of the groove throughout the pivot of the forks. Torque can be transferred through the engaged flanks as the joint is used to convert eccentric rotation to concentric rotation.

Abstract: A sensor and method for use in measuring a physical characteristic of a fluid in a microfluidic system is provided. A microfluidic chip has a thin deformable membrane that separates a microfluidic channel from a microwave resonator sensor. The membrane is deformable in response to loading from interaction of the membrane with the fluid. Loading may be fluid pressure in the channel, or shear stress or surface stress resulting from interaction of the membrane with the fluid. The deformation of the membrane changes the permittivity in the region proximate the sensor. A change in permittivity causes a change in the electrical parameters of the sensor, thereby allowing for a characteristic of the fluid, such as flow rate, or a biological or chemical characteristic, to be measured. Also, a microwave sensor with improved sensitivity for characterizing a fluid in a microfluidic channel is provided.

Abstract: A constant velocity joint for downhole power transmission has a first insert mounted in a radially extending drive shaft arm. The first insert engages a second insert mounted along a slot formed in a tubular housing disposed to receive the arm. The material for the two inserts may be different, having different galling properties. An insert may be shaped to have at least a flat surface, a cylindrical surface intersecting the flat surface, and a conical surface intersecting the cylindrical surface. The inserts may extend beyond the cavities in which they are mounted. Opposing cavity walls adjacent the cavity opening may be angled away from one another to permit the insert to flex under a load. The back wall of a cavity and back surface of an insert may be arcuate to permit rotational movement of the insert under a load.

Abstract: A lubrication system includes a pair of mating surfaces subject to relative motion and a source of lubrication in communication with the mating surfaces. A microfluidic channel system including at least one diffuser element is disposed in an interface between the mating surfaces to create a coherent fluid film at the interface in response to the relative motion.

Abstract: Methods and apparatus are disclosed for coupling components within a downhole motor drivetrain, and particularly to improving the torque carrying characteristics through threaded couplings in the drivetrain that extends between the mud motor and the drill bit. The described downhole motor drivetrain includes one or more threaded couplings, with each coupling configured to define a gap to accept a spacer having a dimension within a range of sizes. The dimension of the selected spacer placed in the threaded coupling facilitates establishing a desired balance of the force loading at each of two contact regions of the coupling. In many examples, the two contact regions of the coupling will be located on opposite sides of the threaded region.

Abstract: A drilling apparatus including a housing having a housing bore, a proximal housing end, and a distal housing end, a driveshaft rotatably supported within the housing bore, a fixed first angular offset axially located between the proximal housing end and the distal housing end, and a variable second angular offset axially located between the proximal housing end and the distal housing end. The drilling apparatus may have a reduced stiffness section so that the drilling apparatus bends preferentially at the reduced stiffness section, and the variable second angular offset may be axially located at the reduced stiffness section.

Abstract: An example apparatus for controlling the direction of drilling a borehole includes an outer housing having non-uniform stiffness and an inner housing at least partially within and rotationally independent from the outer housing and having non-uniform stiffness, A drive shaft may be at least partially within the inner housing. At least one of the outer housing and the inner housing may include a tubular structure with at least one of multiple materials with different stiffness, and a portion with less structural material than another portion.

Abstract: A connection for connecting a first member with a second member. The connection includes a torque transmitting connection between the first member and the second member and an axial force transmitting connection between the first member and the second member. The axial force transmitting connection includes a first exterior shoulder on the first member, a second exterior shoulder on the second member, a first collar having a first interior shoulder for engaging with the first exterior shoulder, a second collar having a second interior shoulder for engaging with the second exterior shoulder, and a collar connection between the first collar and the second collar for transmitting an axial force between the first collar and the second collar.

Abstract: The disclosure describes a constant velocity joint assembly for use in transmitting torque. The constant velocity joint assembly includes members that are connected in series via tongue-and-groove connections in a swivel joint pattern that allows for transferring torque between two skew lines, and further provide freedom of movement such that rotation about one longitudinal axis can be transformed into rotation about another longitudinal axis that is not aligned with the first longitudinal axis. Thus, the members of the constant velocity joint assembly do not necessarily need to share a common longitudinal axis.

Abstract: A axial retention connection for a downhole tool is disclosed. The connection includes a drill string component including a socket having a plurality of walls and a top surface. The connection additionally includes a downhole tool coupled to the socket, the downhole tool including a male-type connector having an outer perimeter and a top surface. The connection further includes a seal between the drill string component and the downhole tool. The connection further includes a chamber formed by the plurality of walls and the top surface of the socket and the top surface of the male-type connector; and a fluid filling the chamber.

Abstract: A constant velocity joint for downhole power transmission has a first insert mounted in a radially extending drive shaft arm. The first insert engages a second insert mounted along a slot formed in a tubular housing disposed to receive the arm. The material for the two inserts may be different, having different galling properties. An insert may be shaped to have at least a flat surface, a cylindrical surface intersecting the flat surface, and a conical surface intersecting the cylindrical surface. The inserts may extend beyond the cavities in which they are mounted. Opposing cavity walls adjacent the cavity opening may be angled away from one another to permit the insert to flex under a load. The back wall of a cavity and back surface of an insert may be arcuate to permit rotational movement of the insert under a load.

Abstract: A lubrication system includes a pair of mating surfaces subject to relative motion and a source of lubrication in communication with the mating surfaces. A microfluidic channel system including at least one diffuser element is disposed in an interface between the mating surfaces to create a coherent fluid film at the interface in response to the relative motion.

Abstract: Methods and apparatus are disclosed for coupling components within a downhole motor drivetrain, and particularly to improving the torque carrying characteristics through threaded couplings in the drivetrain that extends between the mud motor and the drill bit. The described downhole motor drivetrain includes one or more threaded couplings, with each coupling configured to define a gap to accept a spacer having a dimension within a range of sizes. The dimension of the selected spacer placed in the threaded coupling facilitates establishing a desired balance of the force loading at each of two contact regions of the coupling. In many examples, the two contact regions of the coupling will be located on opposite sides of the threaded region.

Abstract: Methods and apparatus are disclosed for retaining components in a downhole motor in the event of a mechanical separation or failure of one or more components therein. As described, the retention mechanism does not require a threaded connection to components of the mud motor drivetrain. Downhole motor assemblies including the new catch mechanism also include a structural element to engage the catch assembly and the components to which it is attached in the event of a mechanical failure within the mud motor assembly.

Abstract: A drilling apparatus including a housing having a housing bore, a proximal housing end, and a distal housing end, a driveshaft rotatably supported within the housing bore, a fixed first angular offset axially located between the proximal housing end and the distal housing end, and a variable second angular offset axially located between the proximal housing end and the distal housing end. The drilling apparatus may have a reduced stiffness section so that the drilling apparatus bends preferentially at the reduced stiffness section, and the variable second angular offset may be axially located at the reduced stiffness section.

Abstract: A constant-velocity joint can have three pieces: a yoke, a first adaptor, and a second adaptor. Grooves on opposite sides of the yoke can receive forks of the adaptors and be perpendicular to one another. The yoke can have a guide surface within each groove so that a matching following surface on the fork of the adaptor can engage the guide surface to guide the movement of the fork within the groove. The adaptors may pivot within the grooves such that surfaces of flanks of the forks remain engaged or provide a consistent amount of surface contact with flanks of the groove throughout the pivot of the forks. Torque can be transferred through the engaged flanks as the joint is used to convert eccentric rotation to concentric rotation.

Abstract: An example apparatus for controlling the direction of drilling a borehole includes an outer housing having non-uniform stiffness and an inner housing at least partially within and rotationally independent from the outer housing and having non-uniform stiffness, A drive shaft may be at least partially within the inner housing. At least one of the outer housing and the inner housing may include a tubular structure with at least one of multiple materials with different stiffness, and a portion with less structural material than another portion.

Abstract: A axial retention connection for a downhole tool is disclosed. The connection includes a drill string component including a socket having a plurality of walls and a top surface. The connection additionally includes a downhole tool coupled to the socket, the downhole tool including a male-type connector having an outer perimeter and a top surface. The connection further includes a seal between the drill string component and the downhole tool. The connection further includes a chamber formed by the plurality of walls and the top surface of the socket and the top surface of the male-type connector; and a fluid filling the chamber.

Abstract: A connection for connecting a first member with a second member, including a torque transmitting connection between the first member and the second member and an axial force transmitting connection between the first member and the second member, wherein the axial force transmitting connection includes a first exterior shoulder on the first member, a second exterior shoulder on the second member, a first collar having a first interior shoulder for engaging with the first exterior shoulder, a second collar having a second interior shoulder for engaging with the second exterior shoulder, and a collar connection between the first collar and the second collar for transmitting an axial force between the first collar and the second collar.