Rotary steerable drilling system
A rotary steerable drilling system comprises a rotatable housing having a plurality of steering actuators mounted thereon and movable, individually, between retracted and extended positions, the actuators being electrically controlled, and a battery arranged to supply electrical power to the actuators.
1. A rotary steerable drilling system comprising:
a rotatable housing having a plurality of pistons mounted thereon for reciprocal movement in a radial direction to provide steering inputs;
a plurality of valves positioned to control a flow of high-pressure fluid to individual pistons of the plurality of pistons, the plurality of valves being electrically actuated;
a control unit to control actuation of the plurality of valves during rotation of the rotatable housing, the control unit receiving drilling information from inclination and azimuth sensors, the control unit and the inclination and azimuth sensors being electrically powered;
a battery positioned downhole during operation of the rotary steerable drilling system to supply electrical power to the valves for controlling actuation of the plurality of pistons, the battery also supplying electrical power to the control unit and the inclination and azimuth sensors; and
a sleeve disposed around the plurality of pistons, the sleeve being pivotably mounted to a collar of the rotatable housing by a universal joint, the sleeve being coupled to a drill bit such that actuation of the pistons between retracted and extended positions causes adjustment of the angle of the axis of the sleeve, and the drill bit attached thereto, relative to the axis of the collar.
2. A system according to claim 1 , where the plurality of valves is actuated via actuators which are bi-stable.
3. A system according to claim 1 , wherein the battery is rechargeable.
4. A system according to claim 3 , wherein the battery is rechargeable by being electrically connected to a surface located or otherwise located power source.
5. A system according to claim 1 , wherein the battery also supplies power to other equipment.
6. A system according to claim 5 , wherein the battery supplies power to communications equipment.
7. A system according to claim 1 , further comprising a downhole drilling fluid operated motor.
8. A system according to claim 1 , further comprising a wired drilling pipe connection arrangement whereby electrical power and/or data signals can be transmitted between components of the system.
9. A system according to claim 1 , wherein a downhole motor is connected to the sleeve and is operable to drive the drill bit for rotation.
10. A system according to claim 1 , wherein a downhole motor is connected to the collar and is operable to drive the sleeve for rotation relative to the collar.
11. A system according to claim 1 , wherein a downhole motor is operable to drive the collar for rotation.