Drilling method and apparatus

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.

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.

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.

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.

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.