A bottom hole assembly (BHA) includes a top sub-assembly configured to couple to a downhole conveyance to move into a wellbore that includes completion components secured in the wellbore; a drill bit configured to drill out and remove a first portion of a subset of the completion components; and an expandable reamer including a cutting assembly and configured to adjust between a retracted position in which a diameter of the cutting assembly is less than a diameter of a bore through at least one of the completion components and an activated position in which the diameter of the cutting assembly is greater than the diameter of the bore. The expandable reamer is further configured to remove a second portion of the subset of the completion components in the activated position.

A bottom hole assembly (BHA) includes a top sub-assembly configured to couple to a downhole conveyance to move into a wellbore that includes completion components secured in the wellbore; a drill bit configured to drill out and remove a first portion of a subset of the completion components; and an expandable reamer including a cutting assembly and configured to adjust between a retracted position in which a diameter of the cutting assembly is less than a diameter of a bore through at least one of the completion components and an activated position in which the diameter of the cutting assembly is greater than the diameter of the bore. The expandable reamer is further configured to remove a second portion of the subset of the completion components in the activated position.

A method for mining narrow vein deposit of ore, the narrow vein deposit having a hanging wall and a foot wall, the method comprising: drilling a pilot hole into the narrow vein deposit along a path substantially centrally between the hanging wall and the foot wall to a depth within the vein; following the pilot hole with a larger diameter drilling assembly to fragment the ore into drill cuttings; circulating the drill cuttings to a wellhead; and collecting the drill cuttings for processing to recover the ore therefrom.

A method for mining narrow vein deposit of ore, the narrow vein deposit having a hanging wall and a foot wall, the method comprising: drilling a pilot hole into the narrow vein deposit along a path substantially centrally between the hanging wall and the foot wall to a depth within the vein; following the pilot hole with a larger diameter drilling assembly to fragment the ore into drill cuttings; circulating the drill cuttings to a wellhead; and collecting the drill cuttings for processing to recover the ore therefrom.

Provided is a downhole tool, a well system, and a method for forming a well system. The downhole tool, in at least one aspect, includes a two part drilling and running tool, the two part drilling and running tool including a conveyance, a smaller assembly coupled to an end of the conveyance, and a larger bit assembly slidably coupled to the conveyance, the smaller assembly and larger bit assembly configured to slidingly engage one another downhole to form a combined bit assembly. The downhole tool, in accordance with this aspect, further includes a whipstock assembly coupled to the two part drilling and running tool using a coupling mechanism, and a hydraulically actuated anchoring assembly coupled to a downhole end of the whipstock assembly.

An apparatus for cutting into a subterranean formation includes a body and multiple cutting blades distributed around a circumference of the body. The cutting blades are configured to cut into the subterranean formation in response to being rotated. Each cutting blade includes a ball embedded in the respective cutting blade. At least a portion of the ball protrudes towards the subterranean formation from the respective cutting blade in which the ball is embedded. Each ball is configured to roll against the subterranean formation to reduce friction while the cutting blades are rotating.

A method and apparatus for connected deployable arms off of cylindrical surfaces including an outer cylinder defining an outer circumference and an inner cylinder concentric with the outer cylinder around a central aperture, one or more primary developable mechanisms linked to one or more secondary developable mechanisms. The deployable arms transition from a first closed state wherein the primary developable mechanisms and secondary developable mechanisms are contained entirely within the outer cylinder outer circumference to a second open state wherein the inner cylinder rotates relative to the outer cylinder, forcing the primary developable mechanisms and secondary developable mechanisms to extend outside the outer cylinder outer circumference.

A downhole cutting tool includes a tool body with a cutting element or cutting element pocket thereon. At least a portion of the tool body or an attachment thereto is a metal matrix composite formed from metal carbide particles dispersed in a continuous metal matrix. The metal carbide particles make up less than 45 wt % of the metal matrix composite and/or less than 30 vol % of the metal matrix composite. The continuous metal matrix may also be formed from a metal or metal alloy other than Ni—Si—B and/or have a transverse rupture strength greater than 150 ksi and a fracture toughness over 22 ksi*in.sup.0.5.

A downhole cutting tool includes a tool body with a cutting element or cutting element pocket thereon. At least a portion of the tool body or an attachment thereto is a metal matrix composite formed from metal carbide particles dispersed in a continuous metal matrix. The metal carbide particles make up less than 45 wt % of the metal matrix composite and/or less than 30 vol % of the metal matrix composite. The continuous metal matrix may also be formed from a metal or metal alloy other than Ni—Si—B and/or have a transverse rupture strength greater than 150 ksi and a fracture toughness over 22 ksi*in.sup.0.5.

The present disclosure relates to an underreamer. In one aspect, the underreamer comprises a body, the body comprising at least one pocket therein, the underreamer further comprising at least one cutter secured with respect to the body, at least one actuating mechanism for moving the cutter between a retracted position in the pocket, and an extended position in which only the cutter projects from the body. In one aspect, the or each actuating mechanism comprises a piston for driving extension of the cutter, and a linkage to a cutter arm with respect to which the cutter is mounted, and a return spring for biasing the cutter to the retracted position.