Patent ID: 8950511
Filing Date: 2015-02-10
Classification: E21B,E21D

Abstract:
1. A method for forming a borehole in an earthen formation comprising; rotating a drill bit coupled to a drill stem in a first direction into an earthen formation to form a borehole having a first diameter between an opening of the borehole and a first down hole position; retracting the drill bit to a second down hole position from the first down hole position while retaining the drill bit within the borehole; rotating the drill bit in a second direction causing a side cutting element coupled to the drill bit to engage a side wall at a first location of the borehole and to extend a radial distance from a longitudinal axis of the drill bit that is greater than an outer radius of the drill bit, driving the drill bit back into the borehole while continuing to rotate the drill bit in the second direction to allow the side cutting element to enlarge a portion of the borehole between the first location and a second location that is closer to the first down hole position; reversing the rotation of the drill bit from the second direction to the first direction causing the side cutting element coupled to the drill bit to disengage the side wall and to retract a radial distance from the longitudinal axis of the drill bit that is equal to or less than the outer radius of the drill bit; and removing the drill bit and drill stem from the borehole.