Abstract: An expandable eccentric reamer for placement in a drill string up-hole of a conventional drill bit. The reamer blade is actuated by drilling fluid pressure to radially extend to a drill out diameter greater than a pass-through diameter. The reamer body is shaped to have an eccentric outer surface configuration to accommodate the reamer blade therein. The reamer blade acts as a piston arm in response to drilling fluid pressure and moves along a shaft anchored in a hump region that forms an eccentricity in the outer surface configuration of the body. The reamer blade has an outer edge configuration that positions the cutters thereon to prevent them from engaging a casing of a well borehole upon deployment.

Abstract: An improved bi-center with improved directional stability and wear resistance is disclosed, said bit optimally utilizing a plurality of shaped PDC cutting elements selectively situated about the cutting surfaces of the pilot and the reamer to produce a minimal force imbalance, where further said pilot bit and the reamer are force balanced to further reduce imbalance in the operation of the tool.

Abstract: An improved bi-center with improved directional stability and wear resistance is disclosed, said bit optimally utilizing a plurality of shaped PDC cutting elements selectively situated about the cutting surfaces of the pilot and the reamer to produce a minimal force imbalance, where further said pilot bit and the reamer are force balanced to further reduce imbalance in the operation of the tool.

Abstract: The invention is directed to a bi-center drilling tool adapted to fit within and drill through a casing shoe without damage to the surrounding casing. In one embodiment, the tool comprises a bit body having a proximal and a distal end where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer sections define a bit face including primary and secondary cutting blades and cutting elements disposed on said blades. In this embodiment, the cutting or wear elements disposed on the one or more cutting blades which extend to or are proximate to the pass-through gauge define a selected angle between the line of contact on the cutting or wear elements and the material to be drilled.

Abstract: Although particular detailed embodiments of the apparatus and method have been described herein, it should be understood that the invention is not restricted to the details of the preferred embodiment. Many changes in design, composition, configuration and dimensions are possible without departing from the spirit and scope of the instant invention.

Abstract: A bi-center bit adapted to be consecutively used in casing and in formation without the need of removing the bit from the borehole, the bit comprising a bit body defining a proximal end adapted for connection to a drill string, a distal end and a pass-through gauge, where the distal end defines a pilot bit and an intermediate reamer section, where each the pilot and reamer section define a cutting face. A plurality of cutting or wear elements are situated on cutting blades disposed about the cutting face of the pilot and reamer sections. Cutting or wear elements are disposed on one or more of the blades which extend to or are proximate to the pass-through gauge define an angle between the line of contact on the cutting or wear element and the material to be drilled of between 5-45 degrees.

Abstract: Although particular detailed embodiments of the apparatus and method have been described herein, it should be understood that the invention is not restricted to the details of the preferred embodiment. Many changes in design, composition, configuration and dimensions are possible without departing from the spirit and scope of the instant invention.