Three-dimensional steering tool for controlled downhole extended-reach directional drilling

A three-dimensional steering tool for use in drilling a borehole in an underground formation in which an elongated conduit extends from the surface through the borehole and in which the steering tool is mounted on the conduit near a drill bit for drilling the borehole, the steering tool comprising an integrated telemetry section, rotary section and flex section aligned axially along the steering tool for separately controlling inclination and azimuth angles at the drill bit;

• in which the steering tool includes an elongated drive shaft coupled between the conduit and the drill bit, the drive shaft adapted to be rotatably driven for rotating the drill bit;
• in which the flex section includes a deflection actuator for applying a lateral bending force to the drive shaft for bending the drive shaft to produce a drive shaft deflection angle for making corresponding inclination angle adjustments at the drill bit;
• in which the deflection actuator comprises a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying the lateral bending force to the drive shaft;
• in which the rotary section includes a rotator actuator coupled to the deflection actuator for applying a rotational force to the deflection actuator for changing the rotational angle at which the lateral bending force is applied to the drive shaft for making corresponding azimuth angle adjustments at the drill bit;
• in which the rotator actuator is aligned axially with the deflection housing and rotatably coupled to the deflection housing for transmitting a rotational force to the deflection housing, the rotator actuator movable in proportion to a desired change in the azimuth angle to rotate the deflection housing and the deflection piston for changing the angle at which the lateral bending force is applied;
• and in which the telemetry section measures the inclination angle and the azimuth angle during drilling and compares them with desired inclination and azimuth angle information to produce inclination control signals for operating the deflection actuator to make steering adjustments in the inclination angle and for separately producing azimuth control signals for operating the rotator actuator for making steering adjustments in the azimuth angle.

A three-dimensional steering tool for use in drilling a borehole in an underground formation in which a rotary drill string extends from the surface through the borehole, and the steering tool is coupled to the rotary drill string at one end and to a drill bit at the other end for drilling the borehole, the steering tool comprising an integrated telemetry section, rotary section and flex section aligned axially along the steering tool for separately controlling inclination and azimuth angles at the drill bit;

• in which the steering tool includes an elongated drive shaft coupled between the drill string and the drill bit for rotating with the rotation of the rotary drill string when drilling the borehole;
• in which the flex section comprises a deflection actuator which includes a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying a lateral bending force along a length of the drive shaft during the rotation of the drill string for changing a deflection angle of the drive shaft to thereby make inclination angle steering adjustments at the drill bit;
• the rotary section including a rotator housing aligned axially with the deflection housing and surrounding the drive shaft and rotatably coupled to the deflection housing, and a rotator piston contained in the rotary housing, the rotator piston movable in proportion to a desired change in the azimuth angle, for applying a rotational force to the deflection housing to rotate the deflection housing and the deflection piston to change a rotational angle at which the deflection piston applies the lateral bending force to the drive shaft during rotation of the drill string to thereby make azimuth angle steering adjustments at the drill bit;
• the telemetry section measuring present inclination angles and azimuth angles during drilling and comparing them with desired inclination and azimuth angle information to separately produce inclination control signals for operating the deflection piston and azimuth control signals for operating the rotator piston to make steering adjustments in azimuth.

A 3D steering tool adapted for steering a well drilling apparatus when drilling a borehole in an underground formation, comprising:

• an elongated drive shaft coupled to a drill bit and adapted to be rotatably driven for rotating the drill bit, the drive shaft being bendable laterally to define a deflection angle thereof;
• a deflection actuator for applying a lateral bending force along the length of the drive shaft for bending the drive shaft for making changes in the deflection angle to thereby transmit an inclination angle adjustment to the drill bit;
• the deflection actuator comprising a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying a lateral bending force to the drive shaft;
• a rotator actuator coupled to the deflection actuator for transmitting a rotational force to the deflection actuator to thereby change the rotational angle at which the lateral bending force is applied to the drive shaft to thereby transmit an azimuth angle adjustment to the drill bit;
• in which the rotator actuator is aligned axially with the deflection housing and rotatably coupled to the deflection housing for transmitting a rotational force to the deflection housing, the rotator actuator movable in proportion to a desired change in the azimuth angle to rotate the deflection housing and the deflection piston to thereby change the rotational angle at which the lateral bending force is applied to the drive shaft to transmit to the drill bit an azimuth angle steering adjustment;
• and
• a telemetry system contained on the steering tool for separately controlling the lateral bending force and the rotational force for steering the drill bit along a predetermined course.