An automatic drilling system for automatically regulating the release of the drill string of a drilling rig during the drilling of a borehole, comprising: a drilling fluid pressure sensor; a drilling fluid pressure regulator coupled to said drilling fluid pressure sensor, said drilling fluid pressure regulator measuring changes in drilling fluid pressure and outputting a signal representing those changes; a relay coupled to said drilling fluid pressure regulator, said relay responsive to the output signal of said drilling fluid pressure regulator to supply a drill string control signal at an output thereof; and a drill string controller coupled to said relay wherein a decrease in drilling fluid pressure results in said relay supplying a drill string control signal that operates said drill string controller to effect an increase in the rate of release of said drill string and an increase in drilling fluid pressure results in said relay supplying a drill string control signal that operates said drill string controller to effect a decrease in the rate of release of said drill string. view more

A method for automatically regulating the release of the drill string of a drilling rig drill, comprising the steps of: measuring drilling fluid pressure; producing a signal in response to changes in drilling fluid pressure, said signal representing the changes in drilling fluid pressure; relaying said signal to a drill string controller; and controlling said drill string controller to increase the rate of release of said drill string when said signal represents a decrease in drilling fluid pressure and to decrease the rate of release of said drill string when said signal represents an increase in drilling fluid pressure. view more

A method for automatically regulating the release of the drill string of a drilling rig drill, comprising the steps of: measuring drilling fluid pressure and bit weight; producing a first signal in response to changes in drilling fluid pressure, said first signal representing the changes in drilling fluid pressure; producing a second signal in response to changes in bit weight, said second signal representing the changes in bit weight; selecting any one of said first signal, said second signal, and both said first and said second signals to control the release of said drill string; and relaying said selected signal or signals to a drill string controller which regulates the release said drill string in response to said selected signal or signals. view more