Oscillating shear valve for mud pulse telemetry

An oscillating shear valve system for generating pressure fluctuations in a flowing drilling fluid, comprising:

• a tool housing with an upper end and a lower end, said tool housing adapted to be inserted in a bottom hole drilling assembly, said tool housing having an internal bore adapted to support a pulser assembly;
• a pulser assembly, comprising;
• a non-rotating stator disposed in the flowing drilling fluid, said stator having a plurality of flow passages to channel the drilling fluid;
• a rotor disposed in the flowing drilling fluid proximate the stator, the rotor having a plurality of flow passages matching the plurality of flow passages in the stator;
• a drive motor adapted to drive the rotor in a rotationally oscillating manner, thereby generating pressure fluctuations in the drilling fluid;
• an oil filled pulser housing, said housing having an open end and a closed end, the housing adapted for mounting the drive motor and a drive shaft, the drive shaft having a first end and a second end, said first end adapted for attaching to the motor, and said second end adapted for attaching to the rotor, the housing open end adapted to mount a fluid seal for sealing between the housing and the drive shaft;
• a torsional spring with a first end and a second end, the first end of the torsional spring adapted to attach to the second end of the motor drive shaft, and the second end of the torsional spring adapted to be anchored to the pulser housing;
• and,
• an electronics module for controlling the drive motor.

A method for generating a fast transition in a mud pulse telemetry scheme utilizing a phase shift key encoding (PSK) scheme, comprising;

• utilizing an oscillating shear valve to generate pressure pulses, said oscillating shear valve comprising a non-rotating stator;
• an oscillating rotor, said rotor adapted to rotate in a first direction and a second direction, where said second direction is opposite said first direction;
• an electric motor for driving the rotor;
• and an electronics module to control the motor to move in a periodic oscillatory motion such that the rotor transitions through a zero speed each time the rotor direction is reversed, said electronics module comprising circuitry to enable encoding a date stream using PSK;
• driving the rotor with a first predetermined signal phase relationship,
• changing the drive signal according to the PSK scheme at a predetermined rotor speed, and
• attaining a second predetermined phase relationship in no more than one oscillatory period.

A method for generating a fast transition in a mud pulse telemetry scheme utilizing a frequency shift key encoding (FSK) scheme, comprising;

• utilizing an oscillating shear valve to generate pressure pulses, said oscillating shear valve comprising a non-rotating stator;
• an oscillating rotor, said rotor adapted to rotate in a first direction and a second direction, where said second direction is opposite said first direction;
• an electric motor for driving the rotor;
• and an electronics module to control the motor to move in a periodic oscillatory motion such that the rotor transitions through a zero speed each time the rotor direction is reversed, said electronics module comprising circuitry to enable encoding a date stream using FSK;
• driving the rotor at a first predetermined frequency,
• changing the drive signal according to the FSK scheme at a predetermined rotor speed, and
• attaining a second predetermined frequency in no more than one oscillatory period.

A method for generating a fast transition in a mud pulse telemetry scheme utilizing an amplitude shift key encoding (ASK) scheme, comprising;

• utilizing an oscillating shear valve to generate pressure pulses, said oscillating shear valve comprising a non-rotating stator;
• an oscillating rotor, said rotor adapted to rotate in a first direction and a second direction, where said second direction is opposite said first direction;
• an electric motor for driving the rotor;
• and an electronics module to control the motor to move in a periodic oscillatory motion such that the rotor transitions through a zero speed each time the rotor direction is reversed, said electronics module comprising circuitry to enable encoding a date stream using ASK;
• driving the rotor in an oscillatory periodic motion through a first predetermined rotational angle, thereby generating a first pulse amplitude;
• changing the drive signal according to the ASK scheme at a predetermined rotor speed, and
• driving the rotor in an oscillatory periodic motion through a second predetermined rotational angle, attaining a second pulse amplitude in no more than one oscillatory period.

A method for generating an increased data rate in a mud pulse telemetry scheme by combining an amplitude shift key encoding (ASK) scheme and a frequency shift key encoding scheme (FSK), comprising;

• utilizing an oscillating shear valve to generate pressure pulses, said oscillating shear valve comprising a non-rotating stator;
• an oscillating rotor, said rotor adapted to rotate in a first direction and a second direction, where said second direction is opposite said first direction;
• an electric motor for driving the rotor;
• and an electronics module to control the motor to move in a periodic oscillatory motion such that the rotor transitions through a zero speed each time the rotor direction is reversed, said electronics module comprising circuitry to enable encoding a date stream using a combination of ASK and FSK;
• driving the rotor in an oscillatory periodic motion through a first predetermined rotational angle at a first frequency, thereby generating a first pulse amplitude at a first frequency;
• changing the drive signal according to the ASK and FSK schemes at a predetermined rotor speed, and
• driving the rotor in an oscillatory periodic motion through a second predetermined rotational angle at a second predetermined frequency, thereby attaining a second pulse amplitude at a second frequency in no more than one oscillatory period.

A method for generating an increased data rate in a mud pulse telemetry scheme by combining an amplitude shift key encoding (ASK) scheme and a phase shift key encoding scheme (PSK), comprising;

• utilizing an oscillating shear valve to generate pressure pulses, said oscillating shear valve comprising a non-rotating stator;
• an oscillating rotor, said rotor adapted to rotate in a first direction and a second direction, where said second direction is opposite said first direction;
• an electric motor for driving the rotor;
• and an electronics module to control the motor to move in a periodic oscillatory motion such that the rotor transitions through a zero speed each time the rotor direction is reversed, said electronics module comprising circuitry to enable encoding a date stream using a combination of ASK and PSK;
• driving the rotor in an oscillatory periodic motion through a first predetermined rotational angle at a first phase angle, thereby generating a first pulse amplitude at a first phase;
• changing the drive signal according to the ASK and PSK schemes at a predetermined rotor speed, and,
• driving the rotor in an oscillatory periodic motion through a second rotational angle at a second predetermined phase angle, thereby attaining a second pulse amplitude at a second phase angle in no more than one oscillatory period.