A multi-bladed reaming apparatus for enlarging a subterranean borehole, the apparatus having a tubular body with a plurality of longitudinally-extending, circumferentially-spaced, generally radially-extending blades carrying cutting elements, the blades being unequally spaced about the body. The cutting depth of the cutting elements on at least one of the blades is adjusted to modify the distribution of the depth of cut (DOC) among the cutting elements to substantially equalize the volume of formation material removed by the blades. Wear is reduced and the potential for premature failure of cutting elements on any single blade is alleviated.
A method and apparatus for reaming or enlarging a borehole with the ability to drill cement, cement float equipment, and debris out of a casing without substantial damage to the casing interior or the reaming apparatus.
The drilling assembly includes an eccentric adjustable diameter blade stabilizer, having a housing with a fixed stabilizer blade and a pair of adjustable stabilizer blades, and a bi-center bit, having an eccentric reamer section and a pilot bit, mounted on the eccentric stabilizer. The stabilizer and bit have an alignment mechanism for aligning the fixed blade with the reamer section. The alignment mechanism includes an aperture on the bit which is aligned with an aperture on the stabilizer as the stabilizer is made up on the bit. An alignment member is received by the aligned apertures for maintaining the alignment.
A reamer for drilling a hole having a diameter larger than a pass through diameter in one aspect includes a body having reaming blades affixed at azimuthally spaced apart locations. These blades have cutters attached at selected positions. An outermost surface of each blade conforms to a radially least extensive one, from a longitudinal axis of the reamer, of a pass through and a drill circle, The drill circle is substantially coaxial with the axis. The pass-through circle is axially offset from the drill circle and defines a section wherein the pass-through circle extends from the axis past the drill circle, so that cutters disposed on the reaming blades in the section drill at full drill diameter, while avoiding wall contact at the pass-through diameter. In another aspect, the reamer includes a pilot hole conditioning section including azimuthally spaced apart blades affixed to the body longitudinally ahead of the reaming blades. The pilot blades include a taper at their downhole end, a gauge pad having a diameter substantially equal to the drill diameter of a pilot bit longitudinally ahead of the reamer, and at least one intermediate cutter affixed longitudinally behind the gauge pad. The intermediate cutter is laterally positioned to drill a hole having an intermediate diameter larger than the pilot hole and smaller than the reamer drill diameter. The pilot blades include an intermediate gauge pad having a diameter substantially equal to the intermediate diameter.
A method and apparatus for reaming or enlarging a borehole with the ability to drill cement, cement float equipment, and debris out of a casing without substantial damage to the casing interior or the reaming apparatus. The reaming apparatus also provides enhanced protection from contact with the casing wall for selected structural features and elements thereof.
A reaming tool including a body adapted to couple to a drill string at both axial ends thereof, the body including a plurality of reaming blades affixed at azimuthally spaced apart locations around the circumference of the body, wherein selected ones of the plurality of reaming blades including at least one cutter attached at a selected position and orientation. Additionally, a pilot hole conditioning section including a plurality of azimuthally spaced apart pilot blades affixed to the body longitudinally ahead of the reaming blades. Furthermore, at least one of the reaming blades formed as a single structure with an azimuthally corresponding pilot blade.
