Abstract: A method for regulating an electromagnetic (“EM”) telemetry signal sent from downhole to surface includes determining a value of a controlled parameter of the EM telemetry signal, comparing the value of the controlled parameter to a configuration value, and adjusting the value of the controlled parameter in a first direction towards the configuration value while monitoring a feedback parameter of the EM telemetry signal when the value of the controlled parameter and the configuration value differ. The controlled parameter is one of transmission voltage and transmission current, and the feedback parameter is the other of transmission voltage and transmission current.

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: A fluid pressure pulse generator comprising a stator and rotor that can be used in measurement while drilling using mud pulse or pressure pulse telemetry is disclosed. The stator comprises a stator body with a circular opening therethrough and the rotor comprises a circular rotor body rotatably received in the circular opening of the stator body. One of the stator body or the rotor body comprises one or more than one fluid opening for flow of fluid therethrough and the other of the stator body or the rotor body comprises one or more than one full flow chamber. The rotor is rotatable between a full flow configuration whereby the full flow chamber and the fluid opening align so that fluid flows from the full flow chamber through the fluid opening, and a reduced flow configuration whereby the full flow chamber and the fluid opening are not aligned.

Abstract: This invention comprises systems, methods and apparatus for mud pulse telemetry involving sending benchmark pulses with known characteristics (such as amplitude or duration) from the surface to the BHA, measuring those characteristics at the BHA, using those measurements to predict the likely attenuation of downhole-to-surface mud pulse transmissions, and adjusting those transmissions to compensate for high attenuation or to obtain energy savings (or transmission rate increases) during low-attenuation conditions. Further refinements on these systems and methods, particularly concerning the use of signal-to-noise ratio measurements at the surface to more efficiently predict attenuation, are also disclosed.

Abstract: The embodiments described herein generally relate to a fluid pressure pulse generating apparatus with a primary seal assembly, back up seal assembly and pressure compensation device. The pressure compensation device comprises a membrane support and a longitudinally extending membrane system. The membrane support has a longitudinally extending bore therethrough for receiving a drive-shaft of the fluid pressure pulse generating apparatus. The longitudinally extending membrane system comprising a longitudinally extending outer membrane sleeve and a longitudinally extending inner membrane sleeve with the inner membrane sleeve positioned inside the outer membrane sleeve.

Abstract: The embodiments described herein generally relate to a method for detecting gamma radiation downhole using a downhole probe assembly. The method includes rotating the downhole probe assembly and measuring gamma radiation passing through a window of a gamma sensor module and hitting a gamma sensor therebelow. A gyroscope output is sampled at predetermined time intervals to indicate the speed of rotation of the downhole probe assembly. The angle of rotation of the window is calculated based on the speed of rotation of the downhole probe assembly. Each revolution of the downhole probe assembly is conceptually divided up into a plurality of bins. Measured gamma radiation is allocated to one of the plurality of bins based on the calculated angle of rotation of the window to provide a real time indication of the direction and strength of gamma radiation emitted by the formation surrounding the borehole. This information can be used for real time geosteering of the drill bit during downhole drilling.

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: A fluid pressure pulse generator comprising a stator and rotor that can be used in measurement while drilling using mud pulse or pressure pulse telemetry is disclosed. The stator comprises a stator body with a circular opening therethrough and the rotor comprises a circular rotor body rotatably received in the circular opening of the stator body. One of the stator body or the rotor body comprises one or more than one fluid opening for flow of fluid therethrough and the other of the stator body or the rotor body comprises one or more than one full flow chamber. The rotor is rotatable between a full flow configuration whereby the full flow chamber and the fluid opening align so that fluid flows from the full flow chamber through the fluid opening, and a reduced flow configuration whereby the full flow chamber and the fluid opening are not aligned.

Abstract: An electromagnetic telemetry system adjusts telemetry parameters which may include carrier frequency, signal amplitude and/or data encoding protocol to achieve reliable data transmission and to conserve power. In some embodiments, sweep signals transmit a range of carrier frequencies and the parameters are determined in part by analyzing the received sweep signals. In some embodiments, different parameters are selected automatically based on a mode of drilling.

Abstract: The embodiments described herein generally relate a downhole probe assembly incorporating a Bluetooth device for wirelessly transmitting electrical information between the downhole probe assembly and a surface electronic interface such as a computer when the probe assembly is above ground. The downhole probe assembly includes sensors for sensing downhole conditions; a controller in electrical communication with the sensors and configured to receive and process information from the sensors; a housing enclosing the one or more than one sensor and the controller; the Bluetooth device in electrical communication with the controller; and an end cap assembly fitted at one end of the housing. The end cap assembly partially surrounds the Bluetooth device and is configured for transmission of the electrical information therethrough. Also described is an end cap assembly for fitting to one end of a downhole probe assembly including a transmission module mated with and electrically connected to the Bluetooth device.

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 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: An electromagnetic telemetry signal generating assembly comprises a first section of drill string, a second section of drill string, a gap sub configured to insulate the first section from the second section, and a power source configured to provide a first voltage to a control circuit. The control circuit is configured to drive a second voltage between the sections of drill string. The gap sub provides a gap of at least 12 inches (30 cm). The second voltage may be different than the first voltage.

Abstract: This invention comprises systems, methods and apparatus for mud pulse telemetry involving sending benchmark pulses with known characteristics (such as amplitude or duration) from the surface to the BHA, measuring those characteristics at the BHA, using those measurements to predict the likely attenuation of downhole-to-surface mud pulse transmissions, and adjusting those transmissions to compensate for high attenuation or to obtain energy savings (or transmission rate increases) during low-attenuation conditions. Further refinements on these systems and methods, particularly concerning the use of signal-to-noise ratio measurements at the surface to more efficiently predict attenuation, are also disclosed.

Abstract: An assembly for use in subsurface drilling includes a drill collar section having a bore extending longitudinally through an inner surface of the drill collar section. A pocket is formed in a section of the inner surface of the drill collar section. A holster is located in the pocket and a sleeve is snuggly fitted inside the bore in order to secure the holster inside the pocket. The sleeve may be sealed to the drill collar section for example by seals such as O-rings such that the holster is sealed from the bore. O-rings may be located on one or both of the inside of the inner surface of the collar or on the outside of the sleeve.

Abstract: The embodiments described herein generally relate to a method for detecting gamma radiation downhole using a downhole probe assembly. The method includes rotating the downhole probe assembly and measuring gamma radiation passing through a window of a gamma sensor module and hitting a gamma sensor therebelow. A gyroscope output is sampled at predetermined time intervals to indicate the speed of rotation of the downhole probe assembly. The angle of rotation of the window is calculated based on the speed of rotation of the downhole probe assembly. Each revolution of the downhole probe assembly is conceptually divided up into a plurality of bins. Measured gamma radiation is allocated to one of the plurality of bins based on the calculated angle of rotation of the window to provide a real time indication of the direction and strength of gamma radiation emitted by the formation surrounding the borehole. This information can be used for real time geosteering of the drill bit during downhole drilling.

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: Methods, techniques, and systems for transmitting a data frame of an electromagnetic (EM) telemetry signal to or from a downhole location can be performed using multi-channel transmissions in which at least two different channels at two different frequencies are used to send a long header and the data frame. At least a portion of the long header is transmitted at a first frequency, and at least a portion of the data frame and any remaining portion of the long header not transmitted at the first frequency are transmitted at one or more additional frequencies different from each other and the first frequency. In one example, only two channels are used: one channel is used to transmit all of the long header, another channel is used to transmit all of the data frame, and either of the channels is used to transmit an identifier identifying the type of the data frame.

Abstract: A wireless communications system for a downhole drilling operation comprises surface communications equipment and a downhole telemetry tool. The surface communications equipment comprises a surface EM communications module with an EM downlink transmitter configured to transmit an EM downlink transmission at a frequency between 0.01 Hz and 0.1 Hz. The downhole telemetry tool is mountable to a drill string and has a downhole electromagnetic (EM) communications unit with an EM downlink receiver configured to receive the EM downlink transmission. The downhole EM communications unit can further comprise an EM uplink transmitter configured to transmit an EM uplink transmission at a frequency greater than 0.5 Hz, in which case the surface EM communications module further comprises an EM uplink receiver configured to receive the FIG. 1 EM uplink transmission.

Abstract: Methods, techniques, and systems for transmitting a data frame of an electromagnetic (EM) telemetry signal to or from a downhole location can be performed using multi-channel transmissions in which at least two different channels at two different frequencies are used to send a long header and the data frame. At least a portion of the long header is transmitted at a first frequency, and at least a portion of the data frame and any remaining portion of the long header not transmitted at the first frequency are transmitted at one or more additional frequencies different from each other and the first frequency. In one example, only two channels are used: one channel is used to transmit all of the long header, another channel is used to transmit all of the data frame, and either of the channels is used to transmit an identifier identifying the type of the data frame.