METHOD AND APPARATUS FOR OPTIONAL STRAIGHT HOLE DRILLING OR DIRECTIONAL DRILLING IN EARTH FORMATIONS

摘要

The present invention relates to a method and apparatus for navigational driling in earth formations, the apparatus including a downhole drilling assembly having a drill bit driven by a downhole motor and a deflection element or elements in the assembly for imparting an angle of deflection to the drill bit relative to the drill string above the drilling assembly. At least two stabilization points for the drilling assembly in the borehole are used, with the drill bit, to define an arcuate path for the drilling assembly when the downhole motor is operating but the drill string is not rotating. When the drill string is rotated, the drilling assembly drills a substantially straight or linear borehole.