Method for improved hydraulic jetting of drill bore holes using high pressure pulses of fluid

摘要

Disclosed is a method for generating high-pressure drilling fluid pulses through the nozzles of a directional or "straight ahead" drill bit. One or more balls characterized by a critical compressional force are caused to seat in a jetting nozzle and block it. The pressure in the drill string is then caused to exceed the critical compressional force of the ball such that the ball is blown through the nozzle orifice followed by a bullet-like fluid pulse. A preferred embodiment occurs when the drill bit is attached to the drill string by an extensible hydraulic piston section. The invention has particular application with regard to directional drilling wherein it is desired to deviate the bore hole from a straight vertical path.