Self-adjusting directional drilling apparatus and methods for drilling directional wells

1. An apparatus for drilling curved and straight sections of a wellbore, comprising:

a drilling assembly configured to include a drill bit at an end thereof that is rotatable by a drive in the drilling assembly, the drilling assembly further configured to be connected to a drill pipe that is rotatable from a surface location, wherein the drilling assembly further includes:

a shaft, wherein the shaft is coupled to the drive and the drill bit; and

a housing comprising:

an upper section and a lower section;

a bearing section in the lower section that rotatably couples the shaft to the lower section; and

a pivot member between the upper section and the lower section that couples the upper section to the lower section, wherein the lower section tilts relative to the upper section about the pivot member when the drill pipe is rotationally stationary to allow drilling of a curved section of the wellbore;

wherein the shaft is disposed and configured to be rotated by the drive within the upper section, the lower section, the bearing section, and the pivot member;

wherein rotating the drill pipe causes a reduction of the tilt between the upper section and the lower section when the drill pipe is rotated to allow drilling of a straighter section of the wellbore.

2. The apparatus of claim 1 , further comprising an end stop that limits the tilt to a selected angle.

3. The apparatus of claim 1 , wherein the lower section tilts about the pivot member within a selected plane, and wherein the pivot member is selected from a group consisting of: (i) a pin; and (ii) a ball joint.

4. The apparatus of claim 1 , further comprising a force application device configured to initiate the tilt.

5. The apparatus of claim 4 , wherein the force application device is selected from a group consisting of: (i) a spring that applies a force on the lower section; and (ii) a hydraulic device that applies a force on the lower section in response to a pressure differential.

6. The apparatus of claim 1 , wherein the pivot member has a pivot axis located off a longitudinal axis of the drilling assembly to initiate the tilt when an axial load is applied on the drilling assembly.

7. The apparatus of claim 1 , further comprising a dampener for reducing a rate of the tilt.

8. The apparatus of claim 7 , wherein the dampener reduces variation of the tilt when the drill pipe is rotationally stationary.

9. The apparatus of claim 1 , wherein the drilling assembly further includes a stabilizer that is selected from a group consisting of: (i) a stabilizer below the pivot member; (ii) a stabilizer above the pivot member; and (iii) a stabilizer below the pivot member and a stabilizer above the pivot member.

10. A drilling assembly configured to be connected to a drill pipe and to include a drill bit at an end thereof and a drive for rotating the drill bit for drilling curved and straight sections of a wellbore, the drilling assembly comprising:

a shaft, wherein the shaft is coupled to the drive and the drill bit;

a housing comprising:

an upper section and a lower section;

a bearing section in the lower section that rotatably couples the shaft to the lower section;

pivot member between the upper section and the lower section that couples the upper section to the lower section, wherein the lower section tilts relative to the upper section about the pivot member when the drill pipe is rotationally stationary to allow drilling of a curved section of the wellbore,

wherein the shaft is disposed and configured to be rotated by the drive within the upper section, the lower section, the bearing section, and the pivot member;

wherein rotating the drill pipe reduces the tilt between the upper section and the lower section to allow drilling of a straighter section of the wellbore; and

a dampener that reduces a rate of the tilt.

11. The drilling assembly of claim 10 further comprising a force application device that exerts a force on the lower section to initiate the tilt.

12. The drilling assembly of claim 11 further comprising a stabilizer that aids in initiating the tilt when the drill pipe is rotationally stationary and the drill bit is rotated by the drive.

13. A method of drilling a wellbore, comprising:

conveying a drilling assembly into the wellbore by a drill pipe from a surface location, the drilling assembly including:

a drill bit at an end thereof that is rotatable by a drive in the drilling assembly;

a shaft, wherein the shaft is coupled to the drive and the drill bit;

a housing comprising:

an upper section and a lower section;

a pivot member between the upper section and the lower section that couples the upper section to the lower section, wherein the lower section tilts relative to the upper section about the pivot member when the drill pipe is rotationally stationary to allow drilling of a curved section of the wellbore,

wherein the shaft is disposed and configured to be rotated by the drive within the upper section, the lower section, the bearing section, and the pivot member;

wherein rotating the drill pipe reduces the tilt between the upper section and the lower section to allow drilling of a straighter section of the wellbore;

maintaining the drill pipe rotationally stationary to enable the lower section to tilt relative to the upper section about the pivot member; and

rotating the drill bit by the drive to drill the curved section of the wellbore.

14. The method of claim 13 further comprising: (i) rotating the drill pipe to reduce the tilt; and (ii) drilling the straighter section of the wellbore by applying weight on the drill bit.

15. The method of claim 13 further comprising limiting the tilt to a selected angle during drilling of the curved section via an end stop.

16. The method of claim 13 further comprising providing a dampener that reduces a rate of the tilt when the drill pipe is rotationally stationary.

17. The method of claim 13 further comprising applying a force via a force application device on the lower section to initiate the tilt when the drill pipe is rotationally stationary.

18. The method of claim 17 , wherein the force application device is selected from a group consisting of: (i) a spring that applies a force on the lower section; and (ii) a hydraulic device that applies a force on the lower section in response to a pressure difference.

19. The method of claim 13 further comprising providing a stabilizer that is selected from a group consisting of: (i) a stabilizer below the pivot member; (ii) a stabilizer above the pivot member; and (iii) a stabilizer below the pivot member and a stabilizer above the pivot member.

20. The method of claim 13 wherein the pivot member allows the lower section to tilt within a selected plane.

21. A drilling assembly configured to be rotated in a wellbore from a surface location by rotating a drill pipe coupled thereto, the drilling assembly comprising:

a drive for rotating a drill bit;

a shaft, wherein the shaft is coupled to the drive and the drill bit; and

a housing comprising:

an upper section and a lower section;

a bearing section in the lower section that rotatably couples the shaft to the lower section; and

a pivot member that couples the upper section to the lower section, wherein the lower section tilts relative to the upper section about the pivot member when the drill pipe is rotationally stationary to allow drilling of a curved section of the wellbore,

wherein the shaft is disposed and configured to be rotated by the drive within the upper section, the lower section, the bearing section, and the pivot member;

wherein rotating the drill pipe reduces the tilt between the upper section and the lower section to allow drilling of a straighter section of the wellbore.