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 fluid pulse apparatus for down hole drilling having a turbine assembly actuated by a flow of drilling fluid. The apparatus has a narrowed fluid flow section that cooperates with a piston that moves between an open and a fluid flow restricting position. The apparatus has a turbine assembly that rotates in response to a flow of drilling fluid. The turbine apparatus has upper and lower cam surfaces that cooperate with fixed cam followers such that rotation of the turbine assembly and cam action between the cam surfaces and the fixed followers causes the turbine assembly to reciprocate axially. The piston is fixed to either of the upper or the lower cam surfaces such that as the turbine assembly reciprocates axially, the piston moves between the open and the flow restricting positions to create a pulsed fluid flow.

An example rotating control device may include a bearing assembly with at least one rotating seal and a pressure modulator coupled to the bearing assembly. A controller may be communicably coupled to the pressure modulator. The pressure modulator may be at least one of a mud pulser, a mud siren, and a pressure transducer. The pressure transducer may be a piezoelectric transducer.

An example mud pulse telemetry method includes positioning an external acoustic or vibration sensor on or near a pump to collect acoustic or vibration data during operation of the pump. The method also includes monitoring a pressure of fluid in a tubular, the fluid conveying a data stream as a series of pressure variations. The method also comprises processing the monitored pressure to demodulate the data stream. The processing uses a pump noise estimate obtained at least in part from analysis of the acoustic or vibration data.

A device, system, and method for locating collars along a casing string. The device includes a casing collar locator (CCL) and a valve in communication with the CCL connected to a work string. Fluid is pumped down the work string as the device is used to locate collars along a string. Upon detection of a collar, the CCL sends a signal to the valve, which causes the actuation of the valve to decreases a flow area within a work string. The decrease in flow area causes a pressure increase within the work string, which may be detected at the surface to indicate the detection of a collar. The device may include an amplifier and power source to amplify the signal from the CCL to the valve. The CCL may detect collars by a change in magnetic flux or by the detection of a signal emitted by individual collars.

Methods and apparatus are disclosed for generating fluid pulses in a fluid column, such as within a well. Various described example fluid pulse generators each have a valve structure including a plurality of rollers rotatable around axes that are oriented perpendicular or otherwise angled with respect to the flow direction, the rollers being arranged to collectively at least partially obstruct the cross-sectional area of the fluid conduit. The rotational positions of the rollers may be varied to change the degree of obstruction in the conduit, thereby to generate pressure pulses in the fluid column detectable at a location remote from the fluid pulse generator; these pressure pulses can be used to encode a signal received at the fluid pulse generator.

In some embodiments, an apparatus and a system, as well as a method and an article, may operate to transmit and receive data. Transmission may comprise transforming larger values of acquired data into smaller values of transformed data using a transform defined by a seed value selected to reduce digital pulse position modulation transmission time for the acquired data. Additional activities include digital pulse position modulating the transformed data and a checksum associated with the transformed data to provide a propagation signal, and transmitting the propagation signal into drilling fluid or a geological formation. Reception may comprise receiving the propagation signal, demodulating the propagation signal to extract the transformed data and the checksum, and transforming the transformed data into an estimate of the acquired data, using the transform defined by the seed value validated by the checksum. Additional apparatus, systems, and methods are described.

A flow bypass sleeve for a fluid pressure pulse generator of a downhole telemetry tool. The fluid pressure pulse generator comprising a stator having one or more flow channels or orifices through which drilling fluid flows and a rotor which rotates relative to the stator to move in and out of fluid communication with the flow channels or orifices to create fluid pressure pulses in the drilling fluid flowing through the fluid pressure pulse generator. The flow bypass sleeve is configured to attach to a drill collar which housing the telemetry tool and comprises a body with a bore therethrough which receives the fluid pressure pulse generator. The body includes at least one longitudinally extending bypass channel comprising a groove longitudinally extending along an internal surface of the body or an aperture longitudinally extending through the body. The bypass channel extends across at least a portion of both the stator and the rotor when the fluid pressure pulse generator is received in the flow bypass sleeve such that the drilling fluid flows along the bypass channel as well as flowing through the flow channels or orifices. The bypass channel diverts drilling fluid around the fluid pressure pulse generator and may be dimensioned to control the amount of drilling fluid being diverted.

An apparatus and method to improve transmission of mud pulse telemetry signals is described. A mud pulser is placed in series with a water hammer pulse valve. While generating pulse signals, the mud pulser modulates the flow of mud downstream to the pulse valve. The pulse valve, which cycles at a frequency that is proportional to the flow rate through the tool, operates at a frequency that is effectively modulated by the mud pulser. A sensor that may be at the surface receives a mud pulse signal that comprises both an amplitude modulated component as well as a frequency modulated component.

The invention relates to a wellbore-lining tubing comprising at least one window pre-formed in the wall of the tubing and a device for selectively generating a fluid pressure pulse, and to a method of forming a lateral wellbore employing such a tubing. In an embodiment, a wellbore-lining tubing (130m) is disclosed which comprises: a tubing wall (32m), an internal fluid flow passage (30m), and at least one window (154m) pre-formed in the wall of the tubing; a device (34m) for selectively generating a fluid pressure pulse, the device located at least partly in a space (36m) provided in the wall of the tubing; and a coupling (190) for receiving a deflection tool (192) so that the deflection tool can be secured to the tubing and employed to divert a downhole component (202) through the window in the tubing wall.