Abstract: A guiding sleeve for aligning downhole tubulars includes a body having a first end portion, a second end portion and an intermediate portion extending therebetween. The first end portion is receptive of a terminal end of a first tubular and the second end portion includes a guiding feature that promotes axial alignment of the first tubular with a second tubular.

Abstract: An modular apparatus for generating electrical power in a borehole penetrating the earth includes a body comprising first and second mechanical connectors at opposing ends and first and second electrical connectors at the opposing ends, the mechanical connectors and the electrical connectors being configured to connect with the same type of corresponding connectors on another modular apparatus when the modular apparatus and the another modular apparatus are stacked together. The modular apparatus further includes: an electrical generator having a rotor and stator in mechanical communication with the first and second mechanical connectors and in electrical communication with the first and second electrical connectors; and a turbine wheel coupled to or integrated with the rotor and comprising one or more turbine blades that are configured to interact with fluid flowing through the borehole causing the turbine wheel to rotate and the rotor to rotate in order to generate the electrical power.

Abstract: A drilling assembly for use in drilling of a wellbore is disclosed that in one non-limiting embodiment includes a device that detects a flow-off state, a power generator that generates electrical energy in response to a fluid flowing through the drilling assembly during the flow-off state, and a circuit that utilizes such power to perform one or more selected operations in response to the detection of the flow-off state, including, but not limited to, storing data in a memory; shutting certain devices in the drilling assembly and parking a device in a desired position.

Abstract: A guiding sleeve for aligning downhole tubulars includes a body having a first end portion, a second end portion and an intermediate portion extending therebetween. The first end portion is receptive of a terminal end of a first tubular and the second end portion includes a guiding feature that promotes axial alignment of the first tubular with a second tubular.

Abstract: A guiding sleeve for aligning downhole tubulars includes a body having a first end portion, a second end portion and an intermediate portion extending therebetween. The first end portion is receptive of a terminal end of a first tubular and the second end portion includes a guiding feature that promotes axial alignment of the first tubular with a second tubular.

Abstract: Backflow prevention assemblies and methods for downhole systems having outer strings and inner strings include a housing defining a cavity and being part of the outer string, a flow tube disposed between the inner string and the outer string movable axially within the outer string, and a backflow prevention structure having a flapper and a seal seat, the flapper biased toward a closed position and maintained in an open position by the flow tube. The flapper is housed within the cavity when in the open position and the flapper and seal seat form a fluid seal to prevent fluid flow into or through the flow tube when in the closed position. When the flow tube is moved from a first position that maintains the flapper in the open position to a second position, the backflow prevention structure operates to close the flapper and seal the backflow prevention structure.

Abstract: A power control device includes a communication device configured to be disposed in a borehole and configured to couple electrical power from a power source to a downhole component from a conductor disposed along a borehole string, a circuit breaker system including a first circuit breaker disposed at a connection between the conductor and the downhole component and configured to be closed to connect the downhole component to the conductor, and a controller configured to monitor at least one of a current level and a voltage level at the connection and at the conductor. The controller is configured to control the circuit breaker system and autonomously perform opening the first circuit breaker in response to detecting a deviation in the at least one of the current levels and voltage levels at the connection, to isolate the downhole component from the conductor and the power source.

Abstract: An modular apparatus for generating electrical power in a borehole penetrating the earth includes a body comprising first and second mechanical connectors at opposing ends and first and second electrical connectors at the opposing ends, the mechanical connectors and the electrical connectors being configured to connect with the same type of corresponding connectors on another modular apparatus when the modular apparatus and the another modular apparatus are stacked together. The modular apparatus further includes: an electrical generator having a rotor and stator in mechanical communication with the first and second mechanical connectors and in electrical communication with the first and second electrical connectors; and a turbine wheel coupled to or integrated with the rotor and comprising one or more turbine blades that are configured to interact with fluid flowing through the borehole causing the turbine wheel to rotate and the rotor to rotate in order to generate the electrical power.

Abstract: An modular apparatus for generating electrical power in a borehole penetrating the earth includes a body comprising first and second mechanical connectors at opposing ends and first and second electrical connectors at the opposing ends, the mechanical connectors and the electrical connectors being configured to connect with the same type of corresponding connectors on another modular apparatus when the modular apparatus and the another modular apparatus are stacked together. The modular apparatus further includes: an electrical generator having a rotor and stator in mechanical communication with the first and second mechanical connectors and in electrical communication with the first and second electrical connectors; and a turbine wheel coupled to or integrated with the rotor and comprising one or more turbine blades that are configured to interact with fluid flowing through the borehole causing the turbine wheel to rotate and the rotor to rotate in order to generate the electrical power.

Abstract: An apparatus for generating direct current (DC) electrical energy downhole at a selected voltage includes a drill tubular, a turbine to convert drilling fluid flow energy into rotational energy, an alternator coupled to the turbine to provide AC electrical energy, and an active rectifier configured to rectify the AC electrical energy into DC electrical energy at a controllable voltage. The active rectifier includes (a) a bridge circuit having a circuit branch having first and second rectifier sets including a semiconductor switch in parallel with a diode for each phase of the AC electrical energy and (b) a feedback control loop having a micro-processor and configured to receive an output voltage measurement and a voltage measurement and/or a current measurement in at least one circuit branch as an input and to provide a control signal to each semiconductor switch in order to provide the DC electrical energy at the selected voltage.

Abstract: Backflow prevention assemblies and methods for downhole systems having outer strings and inner strings include a housing defining a cavity and being part of the outer string, a flow tube disposed between the inner string and the outer string movable axially within the outer string, and a backflow prevention structure having a flapper and a seal seat, the flapper biased toward a closed position and maintained in an open position by the flow tube. The flapper is housed within the cavity when in the open position and the flapper and seal seat form a fluid seal to prevent fluid flow into or through the flow tube when in the closed position. When the flow tube is moved from a first position that maintains the flapper in the open position to a second position, the backflow prevention structure operates to close the flapper and seal the backflow prevention structure.

Abstract: A drilling assembly for use in drilling of a wellbore is disclosed that in one non-limiting embodiment includes a device that detects a flow-off state, a power generator that generates electrical energy in response to a fluid flowing through the drilling assembly during the flow-off state, and a circuit that utilizes such power to perform one or more selected operations in response to the detection of the flow-off state, including, but not limited to, storing data in a memory; shutting certain devices in the drilling assembly and parking a device in a desired position.

Abstract: An modular apparatus for generating electrical power in a borehole penetrating the earth includes a body comprising first and second mechanical connectors at opposing ends and first and second electrical connectors at the opposing ends, the mechanical connectors and the electrical connectors being configured to connect with the same type of corresponding connectors on another modular apparatus when the modular apparatus and the another modular apparatus are stacked together. The modular apparatus further includes: an electrical generator having a rotor and stator in mechanical communication with the first and second mechanical connectors and in electrical communication with the first and second electrical connectors; and a turbine wheel coupled to or integrated with the rotor and comprising one or more turbine blades that are configured to interact with fluid flowing through the borehole causing the turbine wheel to rotate and the rotor to rotate in order to generate the electrical power.

Abstract: Examples of high-temperature memory modules used in a well operation are disclosed. In one example implementation according to aspects of the present disclosure, a memory module may include: a control unit configured to receive data from a controller in the well operation and further configured to receive an operating temperature downhole in the well operation and to cause the control unit to initiate a shutdown of the memory module if the operating temperature is greater than a first threshold; and a memory controller configured to receive the data from the control unit and to commit the data to storage medium.

Abstract: A power control device includes a communication device configured to be disposed in a borehole and configured to couple electrical power from a power source to a downhole component from a conductor disposed along a borehole string, a circuit breaker system including a first circuit breaker disposed at a connection between the conductor and the downhole component and configured to be closed to connect the downhole component to the conductor, and a controller configured to monitor at least one of a current level and a voltage level at the connection and at the conductor. The controller is configured to control the circuit breaker system and autonomously perform opening the first circuit breaker in response to detecting a deviation in the at least one of the current levels and voltage levels at the connection, to isolate the downhole component from the conductor and the power source.

Abstract: A downhole system for use in a wellbore in a subterranean formation includes an electromechanical motor or generator. The electromechanical motor or generator may, respectively, be configured convert electricity to mechanical energy or convert mechanical energy in the form of fluid flow for use in one or more downhole tools. The electromechanical motor or generator includes one of a rotor and a stator disposed concentrically around and operatively coupled to the other of the rotor and the stator. A sleeve is disposed concentrically between the rotor and the stator. The sleeve contacts a body to enclose and hermetically seal one of the rotor and the stator therein. The sleeve comprises at least one metal portion and at least one non-magnetic and non-conductive portion. Related methods involve the formation of such a motor or generator.

Abstract: An apparatus for generating direct current (DC) electrical energy downhole at a selected voltage includes a drill tubular, a turbine to convert drilling fluid flow energy into rotational energy, an alternator coupled to the turbine to provide AC electrical energy, and an active rectifier configured to rectify the AC electrical energy into DC electrical energy at a controllable voltage. The active rectifier includes (a) a bridge circuit having a circuit branch having first and second rectifier sets including a semiconductor switch in parallel with a diode for each phase of the AC electrical energy and (b) a feedback control loop having a micro-processor and configured to receive an output voltage measurement and a voltage measurement and/or a current measurement in at least one circuit branch as an input and to provide a control signal to each semiconductor switch in order to provide the DC electrical energy at the selected voltage.

Abstract: A method for transmitting data from a downhole location to a location at the surface of the earth includes: receiving data using a modulator disposed at the downhole location on a drill tubular in a borehole penetrating the earth and modulating the data using offset quadrature phase shift keying (OQPSK) and smooth transitions between phase shifts to produce a series of two-bit symbols having smooth transitions in transition intervals between phase shifts of both in-phase and quadrature-phase components of the OQPSK modulated data. The method further includes transmitting the series of two-bit symbols as an acoustic signal in drilling fluid disposed in the borehole using a mud-pulser, receiving the acoustic signal using a receiver disposed uphole from the downhole location; and demodulating the acoustic signal using a demodulator coupled to the receiver to provide demodulated data.