A method for selecting a drilling fluid pressure pulse transmission frequency in a downhole telemetry tool comprises: emitting a frequency sweep wave in a drilling fluid that comprises pressure pulses over a range of frequencies and over a period of time; measuring a pressure of the drilling fluid at the telemetry tool while the frequency sweep wave is being emitted; determining a signal strength at each frequency in the range of frequencies from the measured pressure of the drilling fluid; and selecting at least one frequency in the range of frequencies that meets a selected signal strength threshold as a telemetry signal transmission frequency for the telemetry tool. The method can further comprise encoding the at least one selected frequency in a header message and transmitting the header message to surface using pressure pulse telemetry, and then encoding telemetry data into a pressure pulse telemetry signal and transmitting the pressure pulse telemetry signal to surface at the at least one selected frequency.

An MWD system with a BHA sensor assembly that can be assembled and tested off-site and then transported to the field and that requires fewer on-site workers to install and operate the system. The BHA sensor assembly can include a sensor for monitoring at least one physical parameter of the BHA and a processor for collecting the data from the sensor, analyzing the data to determine whether a physical condition has been met, and, if so, activating the telemetry system to begin transmitting drilling information to the surface. In some embodiments, a determination that a physical condition has been met can be used to activate or discontinue local logging of data to memory. Data from sensors can also be used to trigger a modification of the types and/or rates of data that are transmitted to the surface and/or logged to memory.

A smart lower end system that can detect multiple events and failures during the generation of pressure pulses by a pulser is disclosed. Pulser failures may occur if the pilot valve fails to fully close or open, if the signal shaft fails to move and close pilot valve orifice, or if movement of the pilot valve or signal shaft is restricted. The components of the smart lower end system may cycle between sleep and wake states to allow for low power operation.

A fluid pressure pulse generator for a downhole telemetry tool comprising a stator and a rotor. The stator comprises a stator flow diverter radially extending across a flow path for fluid flowing through the fluid pressure pulse generator and having one or more than one stator flow channel therethrough through which the fluid flows. The rotor comprises a rotor flow diverter radially extending across the flow path for fluid flowing through the fluid pressure pulse generator and having one or more than one rotor flow channel therethrough through which the fluid flows. The rotor flow diverter is axially adjacent the stator flow diverter and the rotor flow diverter is rotatable relative to the stator flow diverter to move the one or more than one rotor flow channel in and out of fluid communication with the one or more than one stator flow channel to create fluid pressure pulses in the fluid flowing through the fluid pressure pulse generator. A rotor/driveshaft coupling releasably couples the driveshaft of a probe of the tool and the rotor such that the probe can be decoupled from the rotor and removed from a sub housing the fluid pressure pulse generator.

A control valve assembly includes a body having a first mud flow passage defining a mud flow inlet and one or more second mud flow passage portions. A magnetic plunger is slidingly mounted within the body. The magnetic plunger includes one or more third mud flow passage portions each including an inlet section and an outlet section configured to selectively align with the one or more second mud flow passage portions. A solenoid is mounted at the body. The solenoid is selectively activated to shift the magnetic plunger between a first position wherein the third mud flow passage portion is misaligned with the one or more second mudflow passage portions and a second position wherein the third mud flow passage portion aligns with the one or more second mud flow passage portions allowing a pulse of mud to flow through the mud flow passage.

A control valve assembly includes a body including a mud flow passage having a mud flow inlet and a mud flow outlet, a magnetic plunger slidingly mounted within the body, and a solenoid mounted at the body about the magnetic plunger. The solenoid is selectively activated to shift the magnetic plunger between a first position covering the mud flow outlet and a second position exposing the mud flow outlet allowing a pulse of mud to flow through the mud flow passage.

For balancing pressure in a downhole tool between a first section filled with hydraulic fluid and a second section filled with drilling fluid, a system utilizes a sleeve located inside a housing of the downhole tool, a piston located inside the sleeve. A stem traverses the piston through a hole in the piston. The stem is used to couple a solenoid to a valve system of the downhole tool, for example. The piston is sized to control a wobble of the piston and to allow reciprocation of the piston inside the sleeve. The hole in the piston is sized to control a wobble of the stem and to allow reciprocation of the stem through the hole in the piston.

Systems and methods for generating pulses in a drilling fluid are described. The systems are configured to be positioned along a tubular string through which a drilling fluid flows. The systems include a housing supported along the string. A valve stator is supported by the housing and has at least one flow path that extends from an upstream end to a downstream end of the valve stator. A valve rotor is positioned adjacent the valve stator and configured to selectively obstruct the at least one flow path. An axial gap is present between the valve rotor and the valve stator. A motor is coupled to the valve rotor to rotate the valve rotor relative to the valve stator and an axial release assembly having a rotational element is configured to adjust the axial gap between the valve rotor and the valve stator based on a rotation of the rotational element.

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.