Abstract: Drilling mud is flowed through a valve assembly that is set at a particular open amount, measurements are taken of mud flowrate and a force exerted by the drilling mud onto a portion of the valve assembly, and density of the drilling mud is estimated based on historical data. The historical data is generated by directing multiple flows through the valve assembly, where the flows are at different flowrates, and at each flowrate different drilling muds having different densities are directed through the valve assembly. For each flow the valve assembly is adjusted to different open amounts, and a corresponding force exerted by the flow onto the valve assembly is measured. An example of the valve assembly is a mud pulser with a plug member that engages an orifice opening, a sensor in the pulser measures force exerted by the flow of mud.

Abstract: A downhole electromagnetic device includes an antenna wire placed on or at a tool body, a cavity in the tool body having a cavity pressure smaller than a downhole fluid pressure, and an electronic circuit disposed in the cavity. The antenna wire includes an electrical conductor, and an insulator configured to be exposed to a downhole fluid. The device includes an electrical connector connected to an end of the antenna wire, a sealing element configured to seal the connector from the downhole fluid, the sealing element contacting an inner surface of the connector and an outer surface of the insulator, and a first support member configured to support a load applied on the connector by the antenna wire. The connector provides electrical contact between the antenna wire and the electronic circuit, and the load is caused by a differential pressure defined by the downhole fluid pressure and the cavity pressure.

Abstract: A system and method of detecting a vibration of a drill string in a borehole. The drill string is conveyed into the borehole, the drill string including an electrical machine, the electrical machine including a stator and a movable element, the movable element movable relative to the stator, the drill string is rotated in the borehole. A control circuit determines first amplitude of the vibration of the drill string by measuring a signal indicative of a movement of the movable element in the electrical machine due to rotation of the drill string and controls a downhole operation of the drill string based on the detected first amplitude of the vibration.

Abstract: Systems and methods for generating pulses in a drilling fluid are described. The systems are configured to be positioned along a tubular string through which a drilling fluid flows. The systems include a housing supported along the string. A valve stator is supported by the housing and has at least one flow path that extends from an upstream end to a downstream end of the valve stator. A valve rotor is positioned adjacent the valve stator and configured to selectively obstruct the at least one flow path. An axial gap is present between the valve rotor and the valve stator. A motor is coupled to the valve rotor to rotate the valve rotor relative to the valve stator and an axial release assembly having a rotational element is configured to adjust the axial gap between the valve rotor and the valve stator based on a rotation of the rotational element.

Abstract: A system for covering a sensitive component in a downhole string includes a sub section in the downhole string including a longitudinal axis and a reduced diameter portion along the longitudinal axis. The system also includes a guard element, arranged over the reduced diameter portion. The system further includes a mounting system adapted to axially couple the guard element to the sub section. The mounting system includes a pocket in one of the sub section and the guard element, the pocket including a shoulder. The mounting system also includes a threaded bore in the other of the sub section and the guard element, the threaded bore oriented at least partially parallel to the longitudinal axis of the sub section. The mounting system further includes a fastener engaging the threaded bore through the pocket and axially coupling the guard element to the sub section.

Abstract: An apparatus for generating pressure variances in a fluid flowing in a downhole tool having a longitudinal axis includes a flow section having an outer wall, a flow control member selectively blocking flow in the flow section, and an actuator moving the flow control member between a first position wherein the flow control member at least partially blocks flow in the flow section and a second position wherein the flow control member reduces the at least partial blockage of the flow in the flow section. The actuator may be disposed outside the outer wall of the flow section.

Abstract: A downhole electromagnetic device includes an antenna wire placed on or at a tool body, a cavity in the tool body having a cavity pressure smaller than a downhole fluid pressure, and an electronic circuit disposed in the cavity. The antenna wire includes an electrical conductor, and an insulator configured to be exposed to a downhole fluid. The device includes an electrical connector connected to an end of the antenna wire, a sealing element configured to seal the connector from the downhole fluid, the sealing element contacting an inner surface of the connector and an outer surface of the insulator, and a first support member configured to support a load applied on the connector by the antenna wire. The connector provides electrical contact between the antenna wire and the electronic circuit, and the load is caused by a differential pressure defined by the downhole fluid pressure and the cavity pressure.

Abstract: A velocity of a flow of drilling fluid is adjusted to a magnitude that is within the operating range of a mud pulser disposed in the flow of the drilling fluid. A stator in the mud pulser directs the flow of drilling fluid along one or more separate paths. The paths are defined by channels that extend axially along an outer surface of the stator and that are spaced angularly apart from one another. Also in the mud pulser is a rotor that alternatingly blocks the paths. The velocity is adjusted with a plug assembly that blocks flow through a designated channel. One type of plug assembly is a disk with passages that register with less than all of the channels, and that mounts on a downstream end of the stator. Other types of plug assemblies mount in the designated channel to block the flow path.

Abstract: An apparatus for generating pressure variances in a flowing fluid includes a first member having a body and a second member. The second member is displaceable about a rotational axis to at least partially block fluid flow through one or more channels in the first member and at least partially reduce the blockage of this fluid flow. The second member has a hub and at least one section extending axially and radially from the hub relative to the rotational axis of the second member. A related method includes guiding fluid across the first member using the channel(s); selectively blocking the fluid flow through the channel(s) using at least one section of a second member; and moving the second member using an actuator to reduce the blockage of the flow of fluid through the channel(s).

Abstract: A system for covering a sensitive component in a downhole string includes a sub section in the downhole string including a longitudinal axis and a reduced diameter portion along the longitudinal axis. The system also includes a guard element, arranged over the reduced diameter portion. The system further includes a mounting system adapted to axially couple the guard element to the sub section. The mounting system includes a pocket in one of the sub section and the guard element, the pocket including a shoulder. The mounting system also includes a threaded bore in the other of the sub section and the guard element, the threaded bore oriented at least partially parallel to the longitudinal axis of the sub section. The mounting system further includes a fastener engaging the threaded bore through the pocket and axially coupling the guard element to the sub section.

Abstract: A downhole assembly includes a first tubular including a first shoulder and a second tubular including a second shoulder. The assembly further includes a transmission element having a first portion disposed in the first shoulder, the first portion includes an electrically conductive member having a first arc length and a second portion disposed in the second shoulder. The second portion includes a contacting element having a second arc length that is substantially less than the first arc length and further includes an outer insulating carrier that defines a groove. The contacting element is disposed in the groove. When the first tubular is joined to the second tubular, the contacting element contacts the electrically conductive member and the second portion defines at least one region between the electrically conductive member and the second portion in areas of the groove where the contacting element does not contact the electrically conductive member.

Abstract: Systems and methods for generating pulses in a drilling fluid are described. The systems are configured to be positioned along a tubular string through which a drilling fluid flows. The systems include a housing supported along the string. A valve stator is supported by the housing and has at least one flow path that extends from an upstream end to a downstream end of the valve stator. A valve rotor is positioned adjacent the valve stator and configured to selectively obstruct the at least one flow path. An axial gap is present between the valve rotor and the valve stator. A motor is coupled to the valve rotor to rotate the valve rotor relative to the valve stator and an axial release assembly having a rotational element is configured to adjust the axial gap between the valve rotor and the valve stator based on a rotation of the rotational element.

Abstract: A velocity of a flow of drilling fluid is adjusted to a magnitude that is within the operating range of a mud pulser disposed in the flow of the drilling fluid. A stator in the mud pulser directs the flow of drilling fluid along one or more separate paths. The paths are defined by channels that extend axially along an outer surface of the stator and that are spaced angularly apart from one another. Also in the mud pulser is a rotor that alternatingly blocks the paths. The velocity is adjusted with a plug assembly that blocks flow through a designated channel. One type of plug assembly is a disk with passages that register with less than all of the channels, and that mounts on a downstream end of the stator. Other types of plug assemblies mount in the designated channel to block the flow path.

Abstract: A downhole assembly includes a first tubular including a first shoulder and a second tubular including a second shoulder. The assembly further includes a transmission element having a first portion disposed in the first shoulder, the first portion includes an electrically conductive member having a first arc length and a second portion disposed in the second shoulder. The second portion includes a contacting element having a second arc length that is substantially less than the first arc length and further includes an outer insulating carrier that defines a groove. The contacting element is disposed in the groove. When the first tubular is joined to the second tubular, the contacting element contacts the electrically conductive member and the second portion defines at least one region between the electrically conductive member and the second portion in areas of the groove where the contacting element does not contact the electrically conductive member.

Abstract: An apparatus for generating pressure variances in a fluid flowing in a downhole tool having a longitudinal axis includes a flow section having an outer wall, a flow control member selectively blocking flow in the flow section, and an actuator moving the flow control member between a first position wherein the flow control member at least partially blocks flow in the flow section and a second position wherein the flow control member reduces the at least partial blockage of the flow in the flow section. The actuator may be disposed outside the outer wall of the flow section.

Abstract: An apparatus for generating pressure variances in a flowing fluid includes a first member having a body and a second member. The second member is displaceable about a rotational axis to at least partially block fluid flow through one or more channels in the first member and at least partially reduce the blockage of this fluid flow. The second member has a hub and at least one section extending axially and radially from the hub relative to the rotational axis of the second member. A related method includes guiding fluid across the first member using the channel(s); selectively blocking the fluid flow through the channel(s) using at least one section of a second member; and moving the second member using an actuator to reduce the blockage of the flow of fluid through the channel(s).

Abstract: A bottomhole assembly (BHA) has a first section, a second section, and a drilling motor disposed along the second BHA section. The first BHA section is connected to the second BHA section with a flex sub. A steering assembly positioned along the BHA includes a first steering unit and an axially spaced apart second unit. Each steering unit has at least one pad. During operation, the first steering unit generates a force in a first direction and the second steering unit generates a force in a second direction different from the first direction. The first and the second steering units thereby cooperate to axially misalign the first BHA section and the second BHA section at the flex sub.

Abstract: A method and related apparatus for forming a wellbore in a subterranean formation includes forming a drill string that has a drill bit at a distal end, a drilling motor configured to rotate the drill bit with a drive shaft; a joint coupled to the drive shaft; and an actuator assembly displacing the drive shaft between a first and a second deflection angle, the drive shaft being movable at each of the deflection angles until a predetermined weight is applied to the bit. The method also includes conveying the drill bit through the wellbore and fixing the drive shaft in at least one of the first and the second deflection angles by applying a predetermined weight on the bit.

Abstract: A method and related apparatus for forming a wellbore in a subterranean formation includes forming a drill string that has a drill bit at a distal end, a drilling motor configured to rotate the drill bit with a drive shaft; a joint coupled to the drive shaft; and an actuator assembly displacing the drive shaft between a first and a second deflection angle, the drive shaft being movable at each of the deflection angles until a predetermined weight is applied to the bit. The method also includes conveying the drill bit through the wellbore and fixing the drive shaft in at least one of the first and the second deflection angles by applying a predetermined weight on the bit.

Abstract: A bottomhole assembly (BHA) has a first section, a second section, and a drilling motor disposed along the second BHA section. The first BHA section is connected to the second BHA section with a flex sub. A steering assembly positioned along the BHA includes a first steering unit and an axially spaced apart second unit. Each steering unit has at least one pad. During operation, the first steering unit generates a force in a first direction and the second steering unit generates a force in a second direction different from the first direction. The first and the second steering units thereby cooperate to axially misalign the first BHA section and the second BHA section at the flex sub.