Abstract: An initiator circuit for a perforating gun includes a microprocessor structured to perform a circuit-startup algorithm comprising determining whether the circuit supply voltage is stable enough for operation and, if it is, or if a predetermined period of time has passed since powering up the circuit, sending a message indicating the circuit (and thus gun) is ready for operation. The sent message may be a communication uplink indicating an address of the circuit and its ready state or a short burst of pulses indicating the circuit's ready state.

Abstract: Systems and methods for adaptively receiving telemetry data are disclosed. In one example embodiment of a method, mud pulse telemetry data is transmitted from a downhole location. The transmitted data may be received at a plurality of transducers. Each of the transducers may be positioned at a different location of a drilling operation. The received data from the plurality of transducers may be processed simultaneously. The data which most likely corresponds to the transmitted mud pulse telemetry data may be selected and output. In some embodiments received data from the plurality of transducers is processed with a plurality of different decoding chains. Parameters of individual ones of the decoding chains and/or the number of decoding chains may be autonomously varied.

Abstract: A stack of addressable perforating guns with preassigned addresses may be configured for operation by identifying any duplicate addresses in the stack and deduplicating the addresses by assigning new addresses to at least a subset of any guns having the same address until each gun in the stack has an address unique in the stack.

Abstract: An initiator circuit for a perforating gun includes a microprocessor structured to perform a circuit-startup algorithm comprising determining whether the circuit supply voltage is stable enough for operation and, if it is, or if a predetermined period of time has passed since powering up the circuit, sending a message indicating the circuit (and thus gun) is ready for operation. The sent message may be a communication uplink indicating an address of the circuit and its ready state or a short burst of pulses indicating the circuit's ready state.

Abstract: Various downhole logging tools and methods of using and making the same are disclosed. In one aspect a method evaluating cement bond quality in a well is provided. In a well with a particular casing/tubing configuration, waveforms of acoustic energy returning from the tubing and the casing with the tubing present are recorded. A frequency spectrum from the recorded waveforms is determined. Amplitudes of the returning acoustic energy at one or more preselected frequency(s) of interest of a range of frequencies at which the amplitudes are noticeably affected by cement bond quality for the particular casing/tubing configuration are determined. The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality. Other aspects involve time domain analysis.

Abstract: A caliper-arm-position sensor comprising a differential variable reluctance transducer (DVRT) and circuits to drive the DVRT with a substantially sinusoidal signal and to sample a signal at the DVRT once per drive-signal cycle at a predetermined position in the drive-signal cycle is disclosed.

Abstract: Systems, methods and devices for a coaxial cable transmission system. A power supply receives a primary power signal from a power source. The power supply generates a switched direct current power signal from the primary power signal. A power gateway receives the switched direct current power signal over a coaxial cable from the power supply. The power gateway generates a secondary power signal from the switched direct current power signal. A load device receives the secondary power signal from the power gateway. In some implementations, the power supply generates the switched direct current power signal at a positive direct current voltage level for a first part of a time period and at a negative direct current voltage level for a second part of the time period.

Abstract: A system that automates and optimizes the workflows and transportation routes of one or more mobile medical units is provided. The mobile medical units may include mobile phlebotomy units for the onsite collection of medical specimens (e.g., blood). The system may include a plurality of mobile medical units (e.g., medically equipped vans) within a particular city, and a system for receiving and assigning medical workorders to particular mobile units (e.g., based on the mobile unit's location compared to that of the patient, availability, and other criteria). The system also may determine an optimized route to the patient for the mobile unit to follow and may provide additional administrative support to the mobile unit during the entire workflow process. The system also may perform onsite diagnostic tests on medical specimens collected from a patient (e.g., using medical test equipment), may flag abnormal test results, and may communicate the results to a healthcare provider.

Abstract: A ferroresonant transformer assembly comprising, a core, a main shunt, first, second, and third windings, first and second tap connectors, and a selection connector. The first windings configured to be operatively connected to a primary power source. The first tap connector operatively connected to a first intermediate point defined by the third windings. The second tap connector operatively connected to a second intermediate point defined by the third windings. The selection connector operatively connected to the at least one load. Based on voltage requirements of the at least one load, the selection connector is operatively selectively connected to a selected tap connector selected from the first and second tap connectors.

Abstract: Various downhole logging tools and methods of using and making the same are disclosed. In one aspect a method evaluating cement bond quality in a well is provided. In a well with a particular casing/tubing configuration, waveforms of acoustic energy returning from the tubing and the casing with the tubing present are recorded. A frequency spectrum from the recorded waveforms is determined. Amplitudes of the returning acoustic energy at one or more preselected frequency(s) of interest of a range of frequencies at which the amplitudes are noticeably affected by cement bond quality for the particular casing/tubing configuration are determined. The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality. Other aspects involve time domain analysis.

Abstract: Various downhole logging tools and methods of using and making the same are disclosed. In one aspect a method evaluating cement bond quality in a well is provided. In a well with a particular casing/tubing configuration, waveforms of acoustic energy returning from the tubing and the casing with the tubing present are recorded. A frequency spectrum from the recorded waveforms is determined. Amplitudes of the returning acoustic energy at one or more preselected frequency(s) of interest of a range of frequencies at which the amplitudes are noticeably affected by cement bond quality for the particular casing/tubing configuration are determined. The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality. Other aspects involve time domain analysis.

Abstract: A caliper-arm-retention mechanism for a caliper tool is disclosed. The retention mechanism includes a selectively movable retention sleeve and a pivot arm that cooperate to constrain relative translational motion between the pivot arm and a caliper arm pivotally engaged with the pivot arm while at the same time allowing relative rotational movement of the caliper arm and pivot arm. The retention sleeve may be selectively repositioned using a threaded nut configured to push the sleeve toward the pivot arm or pull the sleeve away from the pivot arm, depending on the direction of rotation of the nut.

Abstract: A sensor comprising three electrodes forming two electrode pairs, each pair having a gap between the electrodes, is disclosed. An electrically insulating layer is disposed in the gap of one electrode pair. The sensor may include a RC oscillator circuit connected to the electrode pair having the insulating layer such that the electrode pair contributes to the capacitance of the circuit. The sensor may include a power supply connected to the other electrode pair to provide a voltage across and current through material in the pair's gap. The sensor may be disposed in a borehole to allow borehole fluid to enter the gaps and the RC oscillator circuit and power supply may be operated to provide a measure of capacitance and resistance characteristics of the borehole fluid.

Abstract: Systems, methods and devices for a coaxial cable transmission system. A power supply receives a primary power signal from a power source. The power supply generates a switched direct current power signal from the primary power signal. A power gateway receives the switched direct current power signal over a coaxial cable from the power supply. The power gateway generates a secondary power signal from the switched direct current power signal. A load device receives the secondary power signal from the power gateway. In some implementations, the power supply generates the switched direct current power signal at a positive direct current voltage level for a first part of a time period and at a negative direct current voltage level for a second part of the time period.

Abstract: A foam-level detector is disclosed. The foam-level detector includes mesh disposed on one or more arms attached to a carrier. The carrier is configured to engage a tube so as to be slidable along the longitudinal axis of the tube. The mesh is configured to engage a foam layer such as to float at or near the surface of the foam. The arms may be pivotally attached to the carrier. The carrier may include a magnet configured to magnetically engage a magnet disposed in the tube. The magnet in the tube may be configured to electrically connect two materials, each material having an electrical resistance per unit length of the material. A measure of the resistance of the conductive path formed by the magnet in the tube and the two materials may be used to infer the position of the foam-float along the tube.

Abstract: A sensor comprising three electrodes forming two electrode pairs, each pair having a gap between the electrodes, is disclosed. An electrically insulating layer is disposed in the gap of one electrode pair. The sensor may include a RC oscillator circuit connected to the electrode pair having the insulating layer such that the electrode pair contributes to the capacitance of the circuit. The sensor may include a power supply connected to the other electrode pair to provide a voltage across and current through material in the pair's gap. The sensor may be disposed in a borehole to allow borehole fluid to enter the gaps and the RC oscillator circuit and power supply may be operated to provide a measure of capacitance and resistance characteristics of the borehole fluid.

Abstract: A caliper-arm-retention mechanism for a caliper tool is disclosed. The retention mechanism includes a selectively movable retention sleeve and a pivot arm that cooperate to constrain relative translational motion between the pivot arm and a caliper arm pivotally engaged with the pivot arm while at the same time allowing relative rotational movement of the caliper arm and pivot arm. The retention sleeve may be selectively repositioned using a threaded nut configured to push the sleeve toward the pivot arm or pull the sleeve away from the pivot arm, depending on the direction of rotation of the nut.

Abstract: A caliper-arm-position sensor comprising a differential variable reluctance transducer (DVRT) and circuits to drive the DVRT with a substantially sinusoidal signal and to sample a signal at the DVRT once per drive-signal cycle at a predetermined position in the drive-signal cycle is disclosed.

Abstract: A retrievable receiver for electromagnetic telemetry signals originating from a first wellbore is located in a second wellbore. The receiver uses a casing of the second wellbore as an antenna. A signal pickup unit is provided on a multi-conductor wireline in the second wellbore. The signal pickup provides sensors (e.g. electrodes) for detecting signals at plural locations along the second wellbore. Signal reception can be optimized by adjusting the position of the wireline in the second wellbore and/or selecting sensor(s) for use in receiving the telemetry signals. The receiver may lack any active electronics in the second wellbore.