Auto-adjustable directional drilling apparatus and method

1. An auto-adjustable directional drilling apparatus, comprising:

a drive-shaft housing;

a drill collar coupled to the drive-shaft housing;

a drive shaft passing through the drive-shaft housing and the drill collar;

an active stabilizer fixed to the drive-shaft housing and movably coupled to the drill collar;

a sliding assembly comprising a base support fixed to the drill collar and a sliding base coupled to the drive-shaft housing, wherein the base support defines a slide way and the sliding base is slidably disposed in the slide way; and

an actuating module coupled to the sliding base for driving the sliding base to slide along the slide way, wherein the actuating module shifts the sliding base along the slide way to radially outwardly shift the active stabilizer relative to the drill collar.

2. The apparatus of claim 1 , wherein the actuating module comprises:

a cam defining a groove;

at least one pin slidably disposed in the groove and fixed to the sliding base; and

a motor coupled to the cam for driving the cam to rotate.

3. The apparatus of claim 2 , further comprising a rotation measurement module for measuring the rotation of the cam or the motor.

4. The apparatus of claim 2 , wherein the at least one pin comprises two pins.

5. The apparatus of claim 2 , wherein the actuating module further comprises a drivetrain coupled between the motor and the cam.

6. The apparatus of claim 5 , wherein the drivetrain comprises:

a first gear rotatably coupled to the drill collar and fixed to the cam; and

a second gear coupled between the motor and the first gear.

7. The apparatus of claim 1 , wherein the actuating module comprises a hydraulic actuating module coupled to the sliding base and communicating with fluid inside the drill collar and fluid outside the drill collar to drive the sliding base to slide along the slide way.

8. The apparatus of claim 7 , wherein the hydraulic actuating module comprises:

a hydraulic actuator comprising a body component coupled to the drill collar, and a drive component coupled to the sliding base and defining a first cavity and a second cavity together with the body component; and

a valve comprising a first port communicating with the fluid outside the drill collar, a second port communicating with the fluid inside the drill collar, a third port alternatively communicating the first cavity with the fluid inside or outside the drill collar and a fourth port alternatively communicating the second cavity with the fluid inside or outside the drill collar.

9. The apparatus of claim 8 , wherein the body component is fixed with respect to the drill collar, and the drive component comprises a piston.

10. The apparatus of claim 1 , wherein the drive shaft is coupled to a mud motor.

11. The apparatus of claim 1 , wherein the drive-shaft housing is coupled to the drill collar through a ball joint and a connection pin, the connection pin being located on the ball joint and connected with the drive-shaft housing and the drill collar.

12. The apparatus of claim 1 , wherein the drive shaft is coupled to the drive-shaft housing through a bearing assembly.

13. An auto-adjustable directional drilling method, comprising:

generating a force via an actuating module coupled to a sliding base disposed in a slide way defined by a base support fixed to a drill collar coupled to a drive-shaft housing, an active stabilizer being fixed to the drive-shaft housing and movably coupled to the drill collar; and

utilizing the force to slide the sliding base along the slide way so as to lead to a relative movement between the active stabilizer and the drill collar and generate a bent angle between the drive-shaft housing and the drill collar.