Abstract: A solid-state hydrophone may include a piezoelectric rod positioned between at least two electrodes. The piezoelectric rod may be disposed within a metallic housing to shield the piezoelectric rod and its connections from acoustic and electromagnetic waves. The piezoelectric rod and the electrodes may be potted in the mechanical housing using a potting material that may be positioned adjacent to the piezoelectric rod. At least a layer of the potting material may be positioned between the piezoelectric rod and the metallic housing to physically separate the piezoelectric rod from the metallic housing.

Abstract: A wireline cable, method, and system for broadband communications and data transfer. The wireline cable comprises insulated conductors, arranged such that circumferentially spaced conductors surround a central conductor. One or more of the conductors is insulated with a magnetic permeable insulation configured to reduce electrical interference with an adjacent conductor.

Abstract: A solid-state hydrophone may include a piezoelectric rod positioned between at least two electrodes. The piezoelectric rod may be disposed within a metallic housing to shield the piezoelectric rod and its connections from acoustic and electromagnetic waves. The piezoelectric rod and the electrodes may be potted in the mechanical housing using a potting material that may be positioned adjacent to the piezoelectric rod. At least a layer of the potting material may be positioned between the piezoelectric rod and the metallic housing to physically separate the piezoelectric rod from the metallic housing.

Abstract: A wireline system includes a control system, a downhole tool, and a wireline cable coupling the downhole tool and the control system. The wireline cable includes a plurality of conductors, which includes a core conductor and a concentric conductor disposed around the core conductor, wherein two of the plurality of conductors form a conductor pair, and wherein each of the plurality of conductors is configured to transmit power, data, or both, between the control system and the downhole tool. The wireline cable further includes one or more insulative layers, wherein at least one insulative layer is disposed between any two conductors.

Abstract: A current fed power supply circuit, a method for producing DC voltages from a current source, and a power delivery system are provided herein. One embodiment of a current fed power supply circuit includes: (1) input terminals, (2) an energy storage device having a first end coupled to the input terminals, (3) power switching circuitry coupled to a second end of the energy storage device and including a transformer having a primary winding and a plurality of secondary windings, and (4) multiple output terminals that are each uniquely coupled to one of the plurality of secondary windings, wherein the power switching circuitry converts a current received at the input terminals to a plurality of regulated voltages at the multiple output terminals.

Abstract: Various embodiments include a fiber optic nuclear magnetic resonance (NMR) sensor tool device and systems. One such tool includes a permanent magnet that generates a static magnetic field. A transmit antenna in the tool can operate to transmit a time-varying signal that is orthogonal to the static magnetic field. A fiber optic sensor element includes a coating that phase modulates a light signal traveling in the fiber when the coating is exposed to a varying field (e.g., a received, reflected magnetic field corresponding to the transmitted time-varying signal). The coating may be one of a magnetostrictive coating or a piezoelectric coating. Additional apparatus, systems, and methods are disclosed.

Abstract: A current fed power supply circuit, a method for producing DC voltages from a current source, and a power delivery system are provided herein. One embodiment of a current fed power supply circuit includes: (1) input terminals, (2) an energy storage device having a first end coupled to the input terminals, (3) power switching circuitry coupled to a second end of the energy storage device and including a transformer having a primary winding and a plurality of secondary windings, and (4) multiple output terminals that are each uniquely coupled to one of the plurality of secondary windings, wherein the power switching circuitry converts a current received at the input terminals to a plurality of regulated voltages at the multiple output terminals.

Abstract: A wireline system includes a control system, a downhole tool, and a wireline cable coupling the downhole tool and the control system. The wireline cable includes a plurality of conductors, which includes a core conductor and a concentric conductor disposed around the core conductor, wherein two of the plurality of conductors form a conductor pair, and wherein each of the plurality of conductors is configured to transmit power, data, or both, between the control system and the downhole tool. The wireline cable further includes one or more insulative layers, wherein at least one insulative layer is disposed between any two conductors.

Abstract: A wireline system includes a control system, a downhole tool, and a wireline cable coupling the downhole tool and the control system. The wireline cable includes a plurality of conductors, which includes a core conductor and a concentric conductor disposed around the core conductor, wherein two of the plurality of conductors form a conductor pair, and wherein each of the plurality of conductors is configured to transmit power, data, or both, between the control system and the downhole tool. The wireline cable further includes one or more insulative layers, wherein at least one insulative layer is disposed between any two conductors.

Abstract: A wireline cable, method, and system for broadband communications and data transfer. The wireline cable comprises insulated conductors, arranged such that circumferentially spaced conductors surround a central conductor. One or more of the conductors is insulated with a magnetic permeable insulation configured to reduce electrical interference with an adjacent conductor.

Abstract: A fixture for receiving a tool that facilitates communication between a tool and other equipment. The fixture includes a shroud sized to at least partially cover a circumference of a housing of the tool, and one or more current transformers or sensors which are coupled to the shroud. Each current transformer can inductively receive or inject, through the housing, a current from or into electronics contained within the housing of the tool. The induced current can be part of the communication between the tool and the equipment. The communication can be a data communication between the tool and the equipment, a transfer of electrical power from the equipment to the tool, or both. The tool can be a closed cavity without electrical or magnetic interfaces.

Abstract: A tool for influencing electrically conductive paths using ferrofluids in a downhole system. The downhole system can include a tool body, a source of ferrofluid, and a magnet. The magnet can provide a magnetic field that influences an electrically conductive path within an annulus between the tool body and a wellbore formation by arranging the ferrofluid from the source in the annulus.

Abstract: Downhole electronics assemblies including a modular carrier including a top rail and a bottom rail, the top and bottom rails each including a pair of longitudinally extending sides and the top rail providing one or more ribs that extend between the longitudinally extending sides of the top rail. A circuit board is positionable between the top and bottom rails and has a top side and a bottom side and one or more electronic components mounted on at least one of the top and bottom sides. One or more damping pads interpose the circuit board and a host downhole tool such that contact between the circuit board and the host downhole tool is prevented.

Abstract: A downhole galvanic logging system including a first transmitter electrode configured to convey an exciter current into a formation and a second transmitter electrode configured to receive a return current from the formation. A first transmission line being coupled to the first transmitter electrode and configured to carry the exciter current, and a second transmission line being coupled to the second transmitter electrode and configured to carry the return current. The transmission lines can be arranged in a twisted pattern. A receiver device is positioned between the transmitter electrodes along an axial length of the downhole galvanic logging system. The receiver device can be configured to detect an electrical signal that is proportional to a resistivity of the formation. The second transmitter electrode can be coupled to one end of the receiver device with the second transmission line coupled to the second transmitter electrode through the receiver device.

Abstract: Apparatus and techniques are described, such as for obtaining information indicative of a formation resistivity, such as using information from a galvanic measurement apparatus. A resistive parameter related to a geologic formation is estimated through use of a model. An electrical excitation is coupled from a well tool in a borehole to the geologic formation. Induced voltages resulting from the excitation are received using monitor electrodes selected according to the specified excitation mode, including receiving magnitude and phase information corresponding to the induced voltages. The resistive parameter of the model is then determined using the magnitude and phase information of the received voltages, and using magnitude and phase information about the excitation.

Abstract: A tool for isolating objects in a wellbore using ferrofluids in a downhole system is provided. The downhole system can include a tool body, a source of ferrofluid, and a magnet. The magnet can magnetically couple with the ferrofluid from the source for arranging the ferrofluid adjacent to the tool body for isolating an object positioned in a wellbore from effects of fluids present in the wellbore.

Abstract: Various embodiments include a fiber optic nuclear magnetic resonance (NMR) sensor tool device and systems. One such tool includes a permanent magnet that generates a static magnetic field. A transmit antenna in the tool can operate to transmit a time-varying signal that is orthogonal to the static magnetic field. A fiber optic sensor element includes a coating that phase modulates a light signal traveling in the fiber when the coating is exposed to a varying field (e.g., a received, reflected magnetic field corresponding to the transmitted time-varying signal). The coating may be one of a magnetostrictive coating or a piezoelectric coating. Additional apparatus, systems, and methods are disclosed.

Abstract: A system and method for monitoring a wellbore are disclosed herein. A pulse generator comprises a plurality of ports, wherein a first one of the plurality of ports is coupled to a first location of interest and a second one of the plurality of ports is coupled to a second location of interest. An electromagnetic pulse is generated at the first port and the second port. A reflected electromagnetic pulse is received at the first port and the second port. In another embodiment, the pulses are received at a separate pulse receiver with a plurality of receiving ports. A data storage device is coupled to the pulse generator or the pulse receiver, and data relating to the reflected magnetic pulse is stored at the data storage device.

Abstract: A tool for enhancing or directing magnetic fields using ferrofluids in a downhole system is provided. The downhole system can include a tool body, a source of ferrofluid, and a positioning magnet. The positioning magnet can magnetically couple with the ferrofluid from the source for enhancing or directing a magnetic field through at least a portion of an annulus between the tool body and a wellbore formation.

Abstract: A fixture for receiving a tool that facilitates communication between a tool and other equipment. The fixture includes a shroud sized to at least partially cover a circumference of a housing of the tool, and one or more current transformers or sensors which are coupled to the shroud. Each current transformer can inductively receive or inject, through the housing, a current from or into electronics contained within the housing of the tool. The induced current can be part of the communication between the tool and the equipment. The communication can be a data communication between the tool and the equipment, a transfer of electrical power from the equipment to the tool, or both. The tool can be a closed cavity without electrical or magnetic interfaces.