An electro-acoustic transducer includes a tubular body extending a longitudinal direction and having two end portions, opposing each other longitudinally, and internally having a first chamber, sending with the first end portion and a second chamber, on one side adjacent to and in fluidic communication with the first chamber and on the other side ending with the second end portion. The first end portion is closed towards the outside by a membrane applied to the tubular body. The second end portion has openings that put it in fluidic communication to the outside of the tubular body. The first chamber containing electrical windings arranged in succession to each other in the longitudinal direction. The second chamber is filled with a liquid. A movable element is housed in the first chamber and has a permanent magnets packaged and arranged one above the other, with the magnetization alternating and separated.

An electro-acoustic transducer includes a tubular body extending a longitudinal direction and having two end portions, opposing each other longitudinally, and internally having a first chamber, sending with the first end portion and a second chamber, on one side adjacent to and in fluidic communication with the first chamber and on the other side ending with the second end portion. The first end portion is closed towards the outside by a membrane applied to the tubular body. The second end portion has openings that put it in fluidic communication to the outside of the tubular body. The first chamber containing electrical windings arranged in succession to each other in the longitudinal direction. The second chamber is filled with a liquid. A movable element is housed in the first chamber and has a permanent magnets packaged and arranged one above the other, with the magnetization alternating and separated.

Downhole telemetry systems and related methods adaptively compensate for channel non-linearity effects. To compensate for channel non-linearity, the optimum signal generation parameters are determined that produce the desired modulated pressure variation at the surface. The signal generation parameters are optimized to minimize the discrepancy between the surface detected pressure signal and the intended signal. The mud propagation channel is first estimated in light of the known modulation scheme under an ideal linear-time-invariant channel assumption. The estimated channel is used to synthesize the modulated pressure signal undergoing the mud propagation given the initial signal generation parameters. The method then varies the synthesized signal generation parameters to search for the optimal signal generation parameters. The optimal signal generation parameters are then sent over downlink channel to the downhole pulser, which is ultimately used to generate the pulse waveform.

A pressure pulse generator and an RSS may change the pressure of a fluid flow through a BHA. If the dogleg at the BHA is less than a target dogleg, then the pressure pulse generator goes into pass-through mode to increase the pressure at the RSS and thereby increase a pad force of the RSS steering pads, increasing the severity of the dogleg. If a downhole tool is stuck, then the pressure pulse generator and the RSS are simultaneously actuated to unstick the downhole tool. The RSS is used to generate and transmit pressure pulses to a downhole tool.

A drilling dynamics data recorder is positioned within a slot in a downhole tool. The drilling dynamics data recorder may include a sensor package, the sensor package including one or more drilling dynamics sensors and a processor, the processor in data communication with the one or more drilling dynamics sensors. The drilling dynamics data recorder may also include a memory module, the memory module in data communication with the one or more drilling dynamics sensors and a communication port, the communication port in data communication with the memory module. The drilling dynamics data recorder may further include an electrical energy source, the electrical energy source in electrical communication with the memory module, the one or more drilling dynamics sensors, and the processor.

A drilling dynamics data recorder is positioned within a slot in a downhole tool. The drilling dynamics data recorder may include a sensor package, the sensor package including one or more drilling dynamics sensors and a processor, the processor in data communication with the one or more drilling dynamics sensors. The drilling dynamics data recorder may also include a memory module, the memory module in data communication with the one or more drilling dynamics sensors and a communication port, the communication port in data communication with the memory module. The drilling dynamics data recorder may further include an electrical energy source, the electrical energy source in electrical communication with the memory module, the one or more drilling dynamics sensors, and the processor.

A downhole valve is described. The downhole valve has a pilot valve section and a tool section. The pilot valve section has a first tube. The tool section has a second tube slidably coupled to the first tube of the pilot valve section so as to provide fluid communication between the pilot valve section and the tool section. The tool section can be in the form of a signal valve section of a mud pulse telemetry valve, a reamer, a vertical steerable tool, a rotary steerable tool, a by-pass valve, a packer, a whipstock, or stabilizer.

A downhole valve is described. The downhole valve has a pilot valve section and a tool section. The pilot valve section has a first tube. The tool section has a second tube slidably coupled to the first tube of the pilot valve section so as to provide fluid communication between the pilot valve section and the tool section. The tool section can be in the form of a signal valve section of a mud pulse telemetry valve, a reamer, a vertical steerable tool, a rotary steerable tool, a by-pass valve, a packer, a whipstock, or stabilizer.

A servo valve in a servo pulser used to restrict flow to a larger main valve includes external stops on a housing to define rotational starting/stopping points and sweep zones for a servo rotor having digits for contacting the stops. The digits extend longitudinally away from the servo valve seat and extend into the sweep zones. Interaction between the stops and the digits in the sweep zones limit rotation of the rotor to a swept arc between the stops. The servo pulser rotor oscillates between stopping points in alternating clockwise/counterclockwise sweeps. Each sweep in a given direction creates one full pulse: closed, open, and closed. The servo pulser carries out a feedback/decision loop between hydraulic pulses (and sweeps) that receives information on one or more previous pulses and calculates how fast or slow it should drive the servo rotor for the current pulse.

A downhole telemetry method and system are disclosed. In some embodiment, a method includes driving a pulser device based on an input data stream, wherein driving the pulser device includes generating modulated pressure pulses including modulated pulse shapes within a fluid telemetry medium. In some embodiments in which bi-modulation is utilized, the method further includes driving the pulser device including modulating pressure pulses including pulse position modulating pressure pulses.