Abstract: A system includes a tubing positionable within a wellbore and a first downhole communication device positionable to receive acoustic signals from the tubing and to transmit acoustic signals to the tubing. The system also includes a computing device in communication with the first downhole communication device and including a processor and a non-transitory computer-readable medium that includes instructions that are executable by the processor to perform operations. The operations include receiving a test message including a spectral waveform from a second downhole communication device. The operations further include determining a desired reception frequency for receiving communications from the second downhole communication device using spectral data generated from the spectral waveform. Additionally, the operations include controlling the first downhole communication device to transmit a response message to the second downhole communication device identifying the desired reception frequency.

Abstract: Methods and systems for performing cleaning operations in boreholes penetrating earth formations are described. The methods include obtaining parameter information related to one or more angles of inclination, comparing the obtained parameter information to one or more criteria associated with each respective obtained parameter, generating a cuttings bed model based on the obtained parameter information, obtaining additional parameter information related to the one or more angles of inclination, updating the cuttings bed model in a pseudo-transient manner, determining that a hole cleaning operation is necessary, and at least one of (i) generating an indication that a hole cleaning operation is to be performed and (ii) automatically performing a hole cleaning operation.

Abstract: In some embodiments, a system including a tool drill string having a downhole device is disclosed. The downhole device includes a memory storing instructions and a downhole processor configured to execute the instructions to operate in a first transmission mode by default. The downhole processor is communicatively coupled to an uphole processor via the first transmission mode. The downhole processor is further to transmit, via a second transmission mode, a message to the uphole processor, determine whether a response is received, via the second transmission mode, from the uphole processor, and responsive to determining the response is received from the uphole processor, switch from the first transmission mode to the second transmission mode.

Abstract: In a method for the encryption communication in a process plant, one or more keys for coding of electronic signals regarding the process plant, such as actuation signals, measurement signals, state signals, warning signals or such, are provided. The one or more keys are transmitted as acoustic signal via a ductwork guiding plant fluid, particularly a process fluid or an auxiliary fluid, from the first communication partner to the second communication partner. The process plant can be a chemical plant, a power plant, or a food-processing plant. The communication can be between a first and a second communication partner, which can include at least one field device, such as an actuator for adjusting a process fluid and/or a control electronics for supervising, controlling and/or regulating processes of the process plant.

Abstract: A communication unit for an electrical machine, in particular a hand-held machine tool, includes at least one electrical actuator, a control unit configured to control the at least one electrical actuator, and a receiving unit assigned to a mobile or stationary unit. The at least one electrical actuator and the control unit together form a transmission unit. The transmission unit is configured to transmit data, and the receiving unit is configured to receive the data. The receiving unit includes at least one microphone. To transmit data, via the transmission unit, the control unit is configured to trigger the electrical actuator to generate an acoustic signal that is detectable by the at least one microphone.

Abstract: A method and system for in-sit calibration of a gravimeter. A method may comprise disposing a downhole tool in a borehole, wherein the downhole tool comprises the gravimeter attached to a linear actuator, recording a first set of measurements with the gravimeter while the linear actuator is stationary, activating the linear actuator, recording a second set of measurements with the gravimeter, and calibrating the gravimeter based on the first and second set of recorded measurements. A system may comprise a downhole tool, a conveyance, and an information handling system. The downhole tool may further comprise a hanger, a sonde, connected to the hanger, a linear actuator, connected to the hanger, and a shaft, connected to the linear actuator. The downhole tool may further comprise a linkage, connected to the shaft, a package, connected to the linkage, and a gravimeter, disposed in the package.

Abstract: A transducer system. The system comprises a transducer and circuitry for applying an excitation waveform to excite the transducer during an excitation period. The circuitry for applying has: (i) circuitry for applying a first waveform at a first frequency; and (ii) circuitry for applying a second waveform at a second frequency differing from the first frequency.

Abstract: Methods and systems for performing borehole operations are described. The methods include generating an information signal in a borehole using a pulse generation member, wherein the information signal comprises a pressure variation within a borehole fluid, detecting, in the borehole, a first signal that correlates to the information signal at a first time, detecting, in the borehole, a second signal that correlates to the information signal at a second time, and performing a borehole operation using the first signal and the second signal.

Abstract: In some embodiments, a system including a tool drill string having a downhole device is disclosed. The downhole device includes a memory storing instructions and a downhole processor configured to execute the instructions to operate in a first transmission mode by default. The downhole processor is communicatively coupled to an uphole processor via the first transmission mode. The downhole processor is further to transmit, via a second transmission mode, a message to the uphole processor, determine whether a response is received, via the second transmission mode, from the uphole processor, and responsive to determining the response is received from the uphole processor, switch from the first transmission mode to the second transmission mode.

Abstract: A system for operating in a wellbore in a subterranean formation is described. The system includes a housing, a rotor, a stator, and a controller. The rotor is within the housing and includes a rotatable shaft, a fluid impeller, and a magnetic field source. The magnetic field source is configured to generate a net magnetic field around an entire circumference of the rotor that is uniformly polarized in a single orientation. The stator is within the housing and laterally surrounds the rotatable shaft. The stator is configured to conduct the generated magnetic field to produce a voltage waveform signal. The controller is communicatively coupled to the stator. The controller is configured to receive the voltage waveform signal from the stator and determine an operating characteristic of the rotor based on the received voltage waveform signal.

Abstract: A downhole tool is placed in a borehole of a subsurface formation. The downhole tool comprises a plurality of calipers arranged around a circumference of the downhole tool. A plurality of standoff measurements is received for different rotation angles of the downhole tool, wherein each standoff measurement is indicative of a distance between one of the plurality of calipers and a wall of the borehole. A plurality of apparent diameters of the borehole is determined for the different rotation angles of the downhole tool based on the plurality of standoff measurements and a radius of the downhole tool. A probability function is determined based on the plurality of apparent diameters and at least one of a semiminor axis, semimajor axis, and ellipticity of the borehole is identified based on the probability function.

Abstract: A logging tool is positioned downhole in a wellbore, where the logging tool communicates with a computer on the Earth's surface over an analog signal path. Tool data is received from a sensor associated with the logging tool and encoded into a symbol signal. The symbol signal is transmitted to a receiver system via the analog signal path. The receiver system has one or more filters to filter the symbol signal. The one or more filters includes an equalizer filter indicative of an analog signal path response of the analog signal path. The filtered symbol signal is decoded into second tool data. The second tool data is encoded into second symbols and based on the second symbols, an updated analog signal path response of the analog signal path is generated to update the equalizer filter.

Abstract: The invention discloses an induced drilling method for inertial constraint implicated motion, which is characterized by comprising a motion step of separating weight on bit and torque. The induced drilling method of inertial constraint implicating motion comprises the following steps: step 1, model selection of induced drilling; step 2, potential energy storage of induced drilling, wherein step 2 includes: I, uniform cutting induced drilling under a steady condition; II, distribution of induced drilling shock wave propagation under a transient condition; III, potential energy release of torsion spring in induced drilling under the transient condition; IV, constrained buffer for induced drilling under transient conditions; and V, potential energy compensation for induced drilling under transient conditions. The invention also discloses an inertia constraint induced drilling device accompanying the PDC bit.

Abstract: An acoustic receiver is provided. The acoustic receiver includes an optical vibrometer having an optical emitter and an optical receiver. The optical receiver is operable to emit an optical beam to a single point of reference on a conduit, and the optical receiver is operable to receive one or more reflections of the optical beam off of the single point of reference on the conduit, thereby detecting waves propagating through the conduit created by an acoustic transmitter. A processor is coupled with the optical emitter and the optical receiver. The processor is operable to: determine components of the waves created by the acoustic transmitter based on the one or more reflections of the optical beam; and determine a signal transmitted from the acoustic transmitter based on the components of the waves.

Abstract: Combined wireline and wireless apparatus and related methods are disclosed herein. An example apparatus includes a tool string including a tool bus and a first acoustic repeater coupled to the tool string. The first acoustic repeater is to communicate with a second acoustic repeater to exchange data. The second acoustic repeater is communicatively coupled to a first tool. The first tool is not communicatively coupled to the tool bus.

Abstract: A wellhead port plug assembly having a sensor unit, a plug, a transmitter unit arranged in the sensor unit and comprising a wireless signal transmitter, and a receiver unit arranged on the spool unit and comprising a wireless signal receiver. There is also disclosed a method for installing, removing or replacing a sensor unit located in a port of a wellhead.

Abstract: An acoustic dipole waveform generator has a hollow housing defining an elongate axis and having secured therein at least a force reaction member defining at least a force reaction surface and having hingingly secured thereto an actuator element. The piezoelectric actuator elements define mutually non-aligned length change axes and extend from the reaction member towards at least one moveable piston member hingingly secured to at least one of the actuator elements inside the housing. The piston member is constrained to move in a direction extending perpendicular to the axis, the piston member defining respectively at mutually spaced locations in the housing a pair of heads that, on movement of the piston member, each generate a respective pressure wave and the housing permitting transmission of the wave externally thereby permitting generation of a dipole pressure waveform externally of the housing on changing of the lengths of the actuator elements.

Abstract: A method and system of validating orientation of a core obtained by drilling the core from a subsurface body of material, the method including: a) determining that vibration from drilling is below a nominated level, b) recording data relating to orientation of the core to be retrieved, the data recorded using a downhole core orientation data recording device, c) separating the core from the subsurface body, and d) obtaining from the core orientation data recording device an indication of the orientation of the core based on the recorded data obtained when the vibration from drilling was below the nominated level and before the core was separated from the subsurface body.

Abstract: Methods and apparatus for inspecting oilfield infrastructure components. Methods include estimating an optimal value for at least one excitation parameter for an acoustic excitation source to produce a guided wave of mixed multiple modes in the component; selecting at least one excitation parameter corresponding to an optimal simulated guided wave determined in dependence upon the application of waveform criteria to the time domain waveforms; and generating a guided wave in the tubular using the at least one optimal excitation parameter. Methods may include calculating a guided wave dispersion relation; modeling each of the plurality of simulated guided waves, wherein the modeling comprises generating a time domain waveform for each of a plurality of wave modes in dependence upon the acoustic excitation source; selecting the at least one excitation parameter corresponding to an optimal simulated guided wave determined in dependence upon the application of waveform criteria to the time domain waveforms.

Abstract: An intelligent tool bus network for a bottom hole assembly (BHA) that can enumerate the nodes on the bus to build a tool string layout map. During the enumeration, an enumeration master node (EMN) sequentially powers and tests additional sections of the bus and additional tool electronics. At each node, the EMN records the results of the tests in an enumeration log. For each good node, communication is established with the EMN to retrieve a node ID and node metadata. Using the enumeration log, the EMN builds a tool string layout map that includes information of each node, their relative location, and their operating status. The intelligent tool bus network also facilitates sectioning a bus into a plurality of sub-busses upon a sectioning event and rejoining the sub-busses. The sectioning event occurs as a result of a fault on the bus or a planned section division multiplexing event.

Abstract: A noise detection sensor structure provides hardware-assisted real-time artifact detection on a live bio signal of interest while that signal is being recorded. The structure is configured to detect and analyze the type of external noise, and to use information about the noise type (such as noise level, frequency range of noise, noise source) to improve signal quality and usability of the bio signal. Different algorithms can be used for each noise type detected. In some example cases, for instance, the structure is configured to at least one of extract noise from measurement signal, synchronize measurement with noise signal, change the software filter or analysis algorithm, change gain/filter settings of noise mitigation circuitry, and prompt user to assist as needed, based on the detected noise. Bad signal epochs can be discarded prior to recording, to efficiently use storage. Separate channel(s)/sensor(s) can be used, with different filtering/gain schemes, for noise detection.

Abstract: A method and autodriller for drilling a wellbore with a drill rig by rotating a drillstring and a drill bit with a drill rig drive system; applying an initial weight of the drillstring on the drill rig WOB; measuring drill rig properties to derive an anticipated drill bit rotation speed; and changing the weight of the drillstring on the drill rig WOB so that a corresponding change to the downhole weight on the drill bit occurs approximately simultaneously with a change in the anticipated drill bit rotation speed.

Abstract: Remotely actuated screenout relief valves, systems and methods are disclosed herein. The methods include providing a proppant slurry stream that includes proppant to a casing conduit that is defined by a casing string that extends within a subterranean formation. The methods further include detecting an operational parameter that is indicative of a screenout event within the casing conduit. Responsive to the detecting, the methods include providing a flush fluid stream to the casing conduit, opening the remotely actuated screenout relief valve, and displacing the proppant from the casing conduit into the subterranean formation with the flush fluid stream via the remotely actuated screenout relief valve. The methods may further include closing the remotely actuated screenout relief valve. The systems include hydrocarbon wells that include the remotely actuated screenout relief valve and/or hydrocarbon wells that include controllers that are configured to perform at least a portion of the methods.

Abstract: Ultrasonic transmitting elements in an electroacoustical transceiver transmit acoustic energy to an electroacoustical transponder, which includes ultrasonic receiving elements to convert the acoustic energy into electrical power for the purposes of powering one or more sensors that are electrically coupled to the electroacoustical transponder. The electroacoustical transponder transmits data collected by the sensor(s) back to the electroacoustical transceiver wirelessly, such as through impedance modulation or electromagnetic waves. A feedback control loop can be used to adjust system parameters so that the electroacoustical transponder operates at an impedance minimum. An implementation of the system can be used to collect data in a vehicle, such as the tire air pressure. Another implementation of the system can be used to collect data in remote locations, such as in pipes, enclosures, in wells, or in bodies of water.

Abstract: A downhole repeater network timing system for a drilling rig including a drillstring extending subsurface downwardly from a surface wellhead. The system includes a node located at the drillstring lower end and including a sensor adapted for providing a signal data set output corresponding to downhole drilling conditions. Multiple nodes are located downhole between the Bottom Hole Assembly (BHA) and the wellhead and are associated with the drillstring. The nodes are adapted for receiving and transmitting the signals. The timing control system is adapted for controlling all times within a timeframe according to pre-configured constants known to all nodes. A downhole low rate linear repeater network timing method uses the system.

Abstract: An audio/video (A/V) hub that coordinates playback of audio content is described. In particular, the A/V hub may calculate current time offsets between clocks in electronic devices (such as electronic devices that include speakers) and a clock in the A/V hub based on measured sound corresponding to one or more acoustic-characterization patterns, one or more times when the electronic devices output the sound and the one or more acoustic-characterization patterns. Then, the A/V hub may transmit, to the electronic devices, one or more frames that include audio content and playback timing information, which may specify playback times when the electronic devices are to playback the audio content based on the current time offsets. Moreover, the playback times of the electronic devices may have a temporal relationship so that the playback of the audio content by the electronic devices is coordinated.

Abstract: A communication method is provided for a communication system comprising a transmitter and a receiver. The method involves communicating data from the transmitter to the receiver over a banded communication channel. The method comprises: applying a forward error correction, FEC, code to data to be transmitted to obtain FEC-encoded data; assigning the FEC-encoded data into a plurality of sub-channels; modulating the data from each of the plurality of sub-channels into a corresponding one of a plurality of sub-bands, the plurality of sub-bands having spaced apart center frequencies; and concurrently transmitting the data from the plurality of sub-bands onto a banded communication channel, the banded communication channel comprising one or more pass-bands and one or more stop-bands.

Abstract: A well installation communication system includes downhole metallic structure 2, a downhole communication unit 3, and a surface communication unit 4 arranged for electrical signal communication with the downhole communication unit via a signal channel. The signal channel includes a portion of the downhole metallic structure 2, a portion of cable 5 running within the downhole metallic structure away from said portion of the downhole metallic structure towards the surface and a connection device 6. The connection device 6 is in the signal channel between the portion of metallic structure 2 and the portion of cable 5. The connection device is removeably deployed in the metallic structure, is electrically disconnectably and reconnectably connected to the metallic structure and has a connector portion to which an end of the cable is mechanically and electrically connected.

Abstract: A system and method for installing a tubular in a wellbore, of which the method includes coupling a fluid connector tool to a lifting assembly, coupling a casing fill-up and circulation seal assembly to the fluid connector tool, and coupling two segments of casing together to form a casing string. At least one of the segments of casing is fluidically coupled to the casing fill-up and circulation seal assembly. The method also includes running the casing string into a wellbore, pumping a first fluid from the lifting assembly, through the fluid connector tool and the casing fill-up and circulation seal assembly, and into the casing string as the casing string is run into the wellbore, de-coupling the casing fill-up and circulation seal assembly from the fluid connector tool, and coupling a drill-pipe seal assembly to the fluid connector tool.

Abstract: A range of apparatus and methods for providing local and long range data telemetry within a wellbore is described. These apparatus and methods may be combined in a wide variety of ways. In some embodiments data is transmitted across a gap in a drill string using signals of a higher frequency for which an electrical impedance of the gap or of a filter connected across the gap is low. Low-frequency EM telemetry signals may be applied across the gap. The gap and any filter connected across the gap present a high impedance to the low-frequency EM telemetry signals. The described technology may be applied for transferring sensor readings between downhole electrical packages. In some embodiments sensors are electrically connected across electrically insulating gaps in the drill string.

Abstract: A downhole completion system includes an intermediate casing, an outer production casing arranged at least partly within the intermediate casing, a main barrier to seal between the intermediate casing and the outer production casing, and an inner production casing arranged at least partly within the outer production casing. The outer production casing has a first outer inductive coupling arranged below the main barrier, and a first inner inductive coupling is arranged on an outer face of the inner production casing for wireless transfer of communication signals and/or power therebetween. The first inner inductive coupling is connected to the top of the borehole via a first electrical conductor, and a second outer inductive coupling is arranged on an outer face of the outer production casing and connected with the first outer inductive coupling via a second electrical conductor.

Abstract: The wettability of a formation may be estimated using a multi-frequency dielectric measurement tool. Multi-frequency dielectric dispersion measurements are made using the multi-frequency dielectric measurement tool on a sample. The bulk density and the total porosity of the sample are also otherwise acquired. The bulk density, matrix permittivity, total porosity, and multi-frequency dielectric dispersion measurements are input into a petrophysical dielectric model and the petrophysical dielectric model is applied to obtain inversion results. A wettability state of the sample is determined using the inversion results and one or more reservoir management decisions are made based on the determined wettability state of the sample. A non-transitory, computer-readable storage medium may be provided that has stored on it one or more programs that provide instructions.

Abstract: A system for providing artificial lift to wellbore fluids having solid buildup removal capabilities includes a pump submerged in wellbore fluids and in fluid communication with a tubular member extending within a wellbore. The pump is oriented to selectively boost a pressure of the wellbore fluids traveling from the wellbore towards an earth's surface. A motor is located within the wellbore providing power to the pump. A seal assembly has a first side connected to the motor and a second side connected to the pump, wherein the pump, the motor and the seal assembly together form a submersible pump string. An ultrasonic device is connected to the submersible pump string and operable to produce pressure waves.

Abstract: A communication method is provided for a communication system comprising a transmitter and a receiver. The method involves communicating data from the transmitter to the receiver over a banded communication channel. The method comprises: applying a forward error correction, FEC, code to data to be transmitted to obtain FEC-encoded data; assigning the FEC-encoded data into a plurality of sub-channels; modulating the data from each of the plurality of sub-channels into a corresponding one of a plurality of sub-bands, the plurality of sub-bands having spaced apart center frequencies; and concurrently transmitting the data from the plurality of sub-bands onto a banded communication channel, the banded communication channel comprising one or more pass-bands and one or more stop-bands.

Abstract: A system includes a distributed acoustic sensing (DAS) optical fiber configured to be disposed with a downhole component, an interrogation device including an optical signal source configured to inject an optical signal into the DAS optical fiber and a receiver configured to detect return signals reflected from sensing locations in the fiber, and an acoustic telemetry unit configured to receive a communication from the downhole component and generate an acoustic signal having a frequency within a selected frequency range and encoded to carry the communication, the acoustic signal applied to a first section of the DAS optical fiber. The system also includes a processor configured to associate a first portion of the return signals with the first section and reproduce the communication based on the first portion, and associate a second portion of the return signals with a second section of the fiber and detect one or more acoustic events.

Abstract: A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.

Abstract: A method and system for enhancing the signal quality of received signals generated by acoustic tools by factoring in feedbacks from the rig operations in an adaptive optimization process. The system may include a transmitter driver circuit and transmitters which can implement signal transmission at selected power, mode and waveforms. The selected power, mode and transmit waveforms may further be generated in the system by making optimal calculations based on realtime information from the downhole data regarding the formation and borehole characteristics.

Abstract: A range of apparatus and methods for providing local and long range data telemetry within a wellbore is described. These apparatus and methods may be combined in a wide variety of ways. In some embodiments data is transmitted across a gap in a drill string using signals of a higher frequency for which an electrical impedance of the gap or of a filter connected across the gap is low. Low-frequency EM telemetry signals may be applied across the gap. The gap and any filter connected across the gap present a high impedance to the low-frequency EM telemetry signals. The described technology may be applied for transferring sensor readings between downhole electrical packages. In some embodiments sensors are electrically connected across electrically insulating gaps in the drill string.

Abstract: Pulse telemetry systems and methods for communicating digital data from a wellbore to a surface unit are presented that include a valve fluidly coupled to drilling fluid. The valve adjusts pressure in a drillpipe to cause pressure transitions within the drilling fluid within the drillpipe to transmit data over the drilling fluid. The valve includes a voice coil actuator for developing the pressure transitions within the drilling fluid. Other systems and methods and are included.

Abstract: An echo communication system has a plurality of triggers disposed within a first distance of each other and a hub separated from the plurality of triggers by at least a second distance that is greater than the first distance. The hub is configured to wirelessly transmit a signal intended for one of the triggers and each of the triggers will re-broadcast the same signal if they are not the intended recipient.

Abstract: Pulse telemetry systems and methods for communicating digital data from a wellbore to a surface unit are presented that include a valve fluidly coupled to drilling fluid. The valve adjusts pressure in a drillpipe to cause pressure transitions within the drilling fluid within the drillpipe to transmit data over the drilling fluid. The valve includes a voice coil actuator for developing the pressure transitions within the drilling fluid. Other systems and methods and are included.

Abstract: The resonant frequency of an example transducer can be adjusted by changing the effective mass of a backing mass using a tuning module. The tuning module includes a electrical source, a switch, and an electromagnetic coil connected in series as an electrical circuit. The electromagnetic coil is mechanically attached to the backing mass, and is disposed within a reservoir of a magneto-rheological fluid enclosed within a casing. When the switch is closed, the electrical source applies a voltage and current to the electromagnetic coil, and induces a localized magnetic field within the magneto-rheological fluid. In response to this localized magnetic field, the magneto-rheological fluid increases in viscosity, assumes properties comparable to a viscoelastic solid, and become affixed to the electromagnetic coil. As the electromagnetic coil is mechanically attached to the backing mass, the solidified magneto-rheological fluid increases the effective mass of the backing mass.

Abstract: Time is tracked in a downhole tool to indicate whether timestamps associated with data samples or events in a log indicate either real time or a duration of time since a certain reset, and to indicate whether the timestamps have been synchronized with a master clock in the tool. The log also records the time and offset of each synchronization event. A computer processes the log to convert all of the timestamps to real-time values and to indicate timestamps that have been estimated and timestamps that were never synchronized to a master clock in the tool. The computer determines an associated uncertainty for each of the estimated timestamps.

Abstract: Procedures are described for monitoring dynamics along a drill string during the drilling process using only surface instrumentation or using a combination of surface and downhole instrumentation. Events such as drill collar whirl may be identified from signatures found in signals generated by an electromagnetic sensor such as a magnetometer and/or from a mechanical sensor such as accelerometer. Additional embodiments are described.

Abstract: A subsea installation kit is described. The kit is provided with a subsea tree, a plurality of tubing sections, a plurality of acoustic repeaters and a mechanical filter. The subsea tree is configured to be coupled to a subsea well having a wellbore. The tubing sections are configured to be connected together to form a tubing string extending from above the tree into the wellbore. The acoustic repeaters are configured to be attached to the tubing string in a spaced apart manner. One of the acoustic repeaters is a last acoustic repeater configured to be attached to the tubing string within or above the tree. The mechanical filter is configured to be connected into the tubing string and form a part of the tubing string above the last acoustic repeater, the mechanical filter configured to cause an attenuation to acoustic signals propagating in the tubing string above the tree.

Abstract: A measurement-while-drilling (MWD) telemetry system comprises a downhole MWD telemetry tool comprising a mud pulse (MP) telemetry unit and an electromagnetic (EM) telemetry unit. The MWD telemetry tool can be configured to transmit data in an EM-only telemetry mode using only the EM telemetry unit, in an MP-only mode using only the MP telemetry unit, or in a concurrent telemetry mode using both the EM and MP telemetry units concurrently. When transmitting data in the concurrent telemetry mode, the telemetry tool can be configured to transmit in a concurrent confirmation mode wherein the same telemetry data is transmitted by each of the EM and MP telemetry units, or in a concurrent shared mode wherein some of the telemetry data is transmitted by the EM telemetry unit, and the rest of the telemetry data is transmitted by the MP telemetry unit. The telemetry tool can be programmed to change its operating telemetry mode in response to a downlink command sent by an operator at surface.

Abstract: The present disclosure is related to methods and apparatuses for acoustic velocity well logging. The method may include estimating a magnitude of a principal horizontal stress in a borehole in a formation. The method may include obtaining a far field stress orientation and making a measurement of near borehole stress orientation. The present disclosure also includes an apparatus configured to be conveyed into a borehole and perform the method. Formation stresses and directions may be estimated.

Abstract: A wireless modem for communication in a network of wireless modems via a communication channel includes a transceiver assembly, transceiver electronics and a power supply. The transceiver electronics include transmitter electronics, receiver electronics and at least one processing unit. The transmitter electronics cause the transceiver assembly to send wireless signals into the communication channel. The receiver electronics decode signals received by the transceiver assembly.

Abstract: A downhole telemetry system usable with a subterranean well comprises at least one pressure pulse generator, at least one pressure transmitter located in an internal tube space in the well and at least one pressure transmitter located in a tubing annulus. The system comprises a packer providing hydraulic isolation of the tubing annulus and at least one transmitter located below the packer and responding to at least one physical quantity characterizing a bottom-hole zone. The system also includes a data encoder located below the packer to read out the transmitter located below the packer and to respond to at least one physical quantity characterizing the bottom-hole zone, a pressure pulse modulator to modulate pressure pulses generated by the pressure pulse generator, a surface-mounted data-collection unit to converts the output data of the transmitters and to provide a surface-mounted data decoder with data for analysis.

Abstract: A method of signal processing includes providing at least a first pressure sensor and a second pressure sensor spaced in a drilling system and using an algorithm to separate the downwardly propagating waves from the upwardly propagating waves. In one or more examples, an algorithm may include determining a velocity of pressure signals in a wellbore, time-shifting and stacking pressure signals from at least the first pressure sensor and the second pressure sensor to determine a downwardly propagating noise signal, and subtracting the downwardly propagating noise signal from at least the signal from the first pressure sensor.