Drilling method and apparatus

Abstract

A method and apparatus for precisely controlling the rotation of a drill string. A sensor monitors the rotation of the drill string and transmits the rotational information to a computer. The computer controls the rotation of the motor driving the drill string and rotates the drill string through an angle input by the operator. The computer may also utilize the sensor's rotational information to oscillate the drill string between two predetermined angles. The computer may also receive orientation information from a downhole tool sensor. The downhole tool information may be combined with the rotational information to enable the computer to accurately reorient the downhole tool. REEXAMINATION RESULTS The questions raised in reexamination proceeding No. 90/011,617, filed Apr. 1, 2011, have been considered, and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e) for ex parte reexaminations, or the reexamination certificate required by 35 U.S.C. 316 as provided in 37 CFR 1.997(e) for inter partes reexaminations.

What is claimed is: 
     
       1. A drill string drive comprising:
 a motor adapted to rotate a drill string; 
 a sensor adapted to detect the rotation a rotational position of said drill string at the surface, wherein the sensor is at the surface; and 
 a computer receiving the rotational information position from said sensor, said computer transmitting control signals to said motor, said computer programmed to control said motor to advance said drill string to a predetermined angle. 
 
     
     
       2. A drill string drive comprising:
 a motor adapted to rotate a drill string; 
 a sensor adapted to detect the rotation of said drill string; and 
 a computer receiving rotational data from said sensor and transmitting control signals to said motor, said computer programmed to control the rotation of said motor, said computer advancing controlling the motor to oscillate the drill string to advance said drill string a predetermined angle in a first direction and then reversing to reverse said rotation and advancing to advance said drill string a predetermined angle in a second direction. 
 
     
     
       3. A drilling system comprising:
 a motor; 
 a drill string connected to said motor; 
 a first sensor adapted to detect the rotation of said motor at the surface, wherein the first sensor is at the surface; 
 a bit at the distal end of said drill string; 
 a second sensor adapted to detect the a downhole orientation of said bit; and 
 a computer adapted to receive information from said first sensor and said second sensor and adapted to control said motor to change the rotation of said motor to achieve a predetermined orientation of said bit. 
 
     
     
       4. A drilling method comprising:
 monitoring the rotation a rotational position of a drill string at the surface with a sensor at the surface; 
 transmitting said rotational information regarding the rotational position to a computer; 
 controlling a motor that rotates said drill string with said computer, wherein controlling is performed in response to receiving the information; and 
 rotating said drill string to a predetermined angle. 
 
     
     
       5. A drilling method comprising:
 monitoring the rotation of a drill string with a sensor;   transmitting said rotational information to a computer;   controlling a motor that rotates said drill string with said computer; and   oscillating said drill string between predetermined angles.   
     
     
       6. A directional drilling method comprising:
 monitoring the rotation of a drill string at the surface with a first sensor at the surface; 
 monitoring the a downhole orientation of a downhole tool with a second sensor, said downhole tool being connected to the end of said drill string; 
 transmitting said drill string rotational information to said computer; 
 transmitting said downhole tool orientation information to said computer; 
 controlling a motor that rotates said drill string with said computer; and 
 rotating said drill string with said computer controlled motor to a predetermined angle such that said downhole tool is rotated to a predetermined orientation. 
 
     
     
       7. The drill string drive of claim 1, wherein said computer is adapted to control said motor to advance said drill string to the predetermined angle without substantially disturbing a steering process.  
     
     
       8. The drill string drive of claim 1, wherein said computer is adapted to control said motor to advance said drill string to the predetermined angle without rotating a downhole tool.  
     
     
       9. The drill string drive of claim 1, wherein said computer is adapted to generate a visual output that illustrates the rotation of said drill string from a neutral position.  
     
     
       10. The drill string drive of claim 1, wherein said computer is adapted to generate a visual output that includes torque information associated with said motor.  
     
     
       11. The drill string drive of claim 1, wherein the predetermined angle corresponds to a particular number of rotations of said drill string over a period of time.  
     
     
       12. The drill string drive of claim 1, wherein said motor includes a hydraulic motor and wherein said computer is adapted to control rotation of said hydraulic motor by controlling the flow of fluid to said hydraulic motor.  
     
     
       13. The drill string drive of claim 12, wherein a first motor actuator valve located in a fluid supply system that is adapted to cause fluid to rotate said hydraulic motor in a first direction when open, and wherein a counterbalance valve located in said fluid supply system is adapted to cause said hydraulic motor to resist external rotation forces in the first direction when said first motor actuator valve is closed.  
     
     
       14. The drill string drive of claim 13, wherein a second motor actuator valve located in said fluid supply system is adapted to cause fluid to rotate said hydraulic motor in a second direction when open, and wherein said counterbalance valve is adapted to cause said hydraulic motor to resist external rotation forces in the second direction when said second motor actuator valve is closed.  
     
     
       15. The drill string drive of claim 1, wherein said motor is capable of rotating said drill string in a range of between about one revolution per minute and about two revolutions per minute.  
     
     
       16. The drill string drive of claim 1, wherein the sensor is adapted to sense rotation about a first axis, and, at the surface, said drill sting is adapted to move rotationally about a second axis laterally spaced apart from the first axis.  
     
     
       17. The drill string drive of claim 2, wherein the computer is adapted to control the motor to oscillate said drill string without substantially disturbing a steering process.  
     
     
       18. The drill string drive of claim 2, wherein the computer is adapted to control the motor to advance said drill string to the predetermined angle in the second direction without substantially disturbing a steering process.  
     
     
       19. The drill string drive of claim 2, wherein the computer is adapted to control the motor to advance said drill string to the predetermined angle in the first direction without rotating a downhole tool.  
     
     
       20. The drill string drive of claim 2, wherein the computer is adapted to control the motor to advance said drill string is advanced to the predetermined angle in the second direction without rotating a downhole tool.  
     
     
       21. The drill string drive of claim 2, wherein the computer is adapted to control the motor to advance said drill string in the first direction from a neutral position, and wherein the computer is adapted to control the motor to advance said drill string in the second direction to the neutral position.  
     
     
       22. The drill string drive of claim 2, wherein the computer is adapted to control the motor to advance said drill string in the first direction from a neutral position, and wherein the computer is adapted to control the motor to advance said drill string in the second direction beyond the neutral position.  
     
     
       23. The drill string drive of claim 22, wherein after the computer is adapted to control the motor to advance said drill string in the second direction beyond the neutral position, said computer the computer is adapted to control the motor to reverse rotation and advance said drill string in the first direction beyond the neutral position.  
     
     
       24. The drill string drive of claim 2, wherein said computer is adapted to generate a visual output that illustrates the rotation of said drill string from a neutral position.  
     
     
       25. The drill string drive of claim 2, wherein said computer is adapted to generate a visual output that includes torque information associated with said motor.  
     
     
       26. The drill string drive of claim 2, wherein the computer is adapted to control the motor to continuously oscillate the drill string without substantially disturbing a steering process.  
     
     
       27. The drilling system of claim 3, wherein said first sensor is adapted to sense rotation about a first axis, and, at the surface, said drill sting is adapted to move rotationally about a second axis laterally spaced apart from the first axis.  
     
     
       28. The drilling system of claim 3, wherein said computer is adapted to control said motor to change the rotation of said motor to achieve a predetermined orientation of said bit in response to receiving information from said first and second sensors.  
     
     
       29. The drilling system of claim 28, wherein the information from said first sensor includes rotational data corresponding to the rotation.  
     
     
       30. The drilling system of claim 29, wherein the rotational data corresponds to a rotational position of said drill string at the surface.  
     
     
       31. The drilling system of claim 29, wherein the rotational data comprises a rotational position of said drill string at the surface.  
     
     
       32. The drilling method of claim 4, wherein said drill string is rotated to the predetermined angle without substantially disturbing a steering process.  
     
     
       33. The drilling method of claim 4, wherein said drill string is advanced to the predetermined angle without rotating a downhole tool.  
     
     
       34. The drilling method of claim 4, further comprising receiving an input at an input device that is communicatively coupled to said computer, wherein the predetermined angle is based on the input and corresponds to a particular number of rotations of said drill string over a period of time.  
     
     
       35. The drilling method of claim 4, further comprising generating a visual output that illustrates the rotation of said drill string from a neutral position.  
     
     
       36. The drilling method of claim 4, further comprising generating a visual output that includes torque information associated with said motor.  
     
     
       37. The drilling method of claim 4, wherein said sensor senses rotation about a first axis, and, at the surface, said drill sting is rotated about a second axis laterally spaced apart from the first axis.  
     
     
       38. The directional drilling method of claim 6, wherein said first sensor senses rotation about a first axis, and, at the surface, said drill sting rotates about a second axis laterally spaced apart from the first axis.  
     
     
       39. The directional drilling method of claim 6, wherein said computer controls said motor in response to said computer receiving the drill string rotational information and the downhole tool orientation information.  
     
     
       40. The directional drilling method of claim 39, wherein said first sensor senses the rotation and provides rotational data corresponding to the rotation.  
     
     
       41. The directional drilling method of claim 40, wherein the rotational data corresponds to a rotational position of the drill string at the surface.  
     
     
       42. The directional drilling method of claim 40, wherein the rotational data comprises a rotational position of said drill string at the surface.