A system and method for conveying a tool to a target sub within a tubular string having a number of subs. Each sub may include at least one ledge or shoulder in or on its interior surface that can be used as a latch stopper or stopper, for receiving and engagement with a latch. The subs may also have a latch deflector or deflector. In one embodiment, the latch deflector is a latch-deflection shoulder protruding into the internal diameter (ID) of the string for deflecting a latch, to be subsequently introduced, out of or into the latch-stopping shoulder. The distance between the latch stopper and the latch deflector, referred to as the “deflection radius,” may be used as an address that uniquely identifies each sub, and can vary from sub to sub.

A magnetic depth of cut controller (DOCC) includes a housing having a body portion with a bore extending into the body portion and a depth of cut (DOC) element positioned at least partially within the bore and having a working face to engage a subterranean formation. The DOC element is moveable within the bore to extend or retract from a first end of the housing. Further, the DOCC includes a magnet secured within the bore of the housing between the DOC element and a second end of the housing. Moreover, the DOCC includes a magnetic fluid disposed within the bore of the housing between the DOC element and the second end of the housing. The magnetic fluid has a viscosity that changes responsive to proximity to the magnet to provide a variable resistance to movement of the DOC element.

A magnetic depth of cut controller (DOCC) includes a housing having a body portion with a bore extending into the body portion and a depth of cut (DOC) element positioned at least partially within the bore and having a working face to engage a subterranean formation. The DOC element is moveable within the bore to extend or retract from a first end of the housing. Further, the DOCC includes a magnet secured within the bore of the housing between the DOC element and a second end of the housing. Moreover, the DOCC includes a magnetic fluid disposed within the bore of the housing between the DOC element and the second end of the housing. The magnetic fluid has a viscosity that changes responsive to proximity to the magnet to provide a variable resistance to movement of the DOC element.

A drill bit has a plurality of cutters secured to the bit body, including a gauge cutter defining a gauge diameter of the drill bit. A reciprocating gauge assembly on the bit comprises a cavity defined in the bit body, a piston reciprocably disposed in the cavity, a wear element on an outwardly facing end of the piston, a piston retainer for moveably retaining the piston in the cavity, and a spring biasing the piston outwardly to a neutral position of the wear element with respect to the gauge diameter. The wear element and piston may be urged inwardly in response to an applied load at the drill bit gauge pad, increasing the lateral depth of cut and thereby controlling the aggressiveness of the bit in response to the load.

A drill bit has a plurality of cutters secured to the bit body, including a gauge cutter defining a gauge diameter of the drill bit. A reciprocating gauge assembly on the bit comprises a cavity defined in the bit body, a piston reciprocably disposed in the cavity, a wear element on an outwardly facing end of the piston, a piston retainer for moveably retaining the piston in the cavity, and a spring biasing the piston outwardly to a neutral position of the wear element with respect to the gauge diameter. The wear element and piston may be urged inwardly in response to an applied load at the drill bit gauge pad, increasing the lateral depth of cut and thereby controlling the aggressiveness of the bit in response to the load.

A vibration damping device for use with a downhole tool having a tool axis may comprise a body coupled to a drill string component. The body may include a longitudinal bore therethrough and at least one lateral bore, the lateral bore having a bore opening and an end wall; an inertial mass slidably disposed in the lateral bore; and a cap mechanically coupled to the lateral bore. The lateral bore may be orthogonal to a radius of the body and may lie in a plane normal to the tool axis. The body may include a plurality of lateral bores, which may be in a co-planar arrangement. Each lateral bore may be blind hole positioned in the body so that it does not intersect the longitudinal bore or another lateral bore. A cap may enclose a lateral bore and fluid may be contained in the bore by the cap.

An in-situ square sample acquisition device and method for a bond contact test of a surrounding rock and a shotcrete layer are provided, the device includes a supporting shell, a fixing structure, hollow adjusting bolts and two borehole positioning frames, a guide hole is provided in a middle of the supporting shell, the frames are slidably fit in the guide hole, a plurality of positioning holes are provided in side walls of each of the frames, and the positioning holes in different frames are distributed in a staggered manner, four corners of the supporting shell are connected with four hollow adjusting bolts respectively, one end of each of the hollow adjusting bolts is fixedly provided with an adjusting nut, four fixing lugs are provided in four corners of each frame respectively, and the fixing structure includes four connecting bolts and four nuts.

A drill bit for removing subterranean formation material in a borehole comprises a bit body comprising a longitudinal axis, a plurality of blades extending radially outward from the longitudinal axis along a face region of the bit body and extending axially along a gauge region of the bit body, and an insert coupled to at least one blade in the gauge region. The insert comprises an elongated body having an upper surface, a lower surface, and a longitudinal axis extending centrally therethrough and intersecting the upper and lower surfaces. The upper surface comprises a bearing surface for supporting for the drill bit and providing a surface on which the subterranean formation being drilled rubs against the insert without exceeding the compressive strength of the selected formation. The insert is coupled to the blade such that the upper surface thereof extends radially beyond an outer surface of the blade and the lower surface thereof extends radially below the outer surface of the blade.

A drill bit for removing subterranean formation material in a borehole comprises a bit body comprising a longitudinal axis, a plurality of blades extending radially outward from the longitudinal axis along a face region of the bit body and extending axially along a gauge region of the bit body, and an insert coupled to at least one blade in the gauge region. The insert comprises an elongated body having an upper surface, a lower surface, and a longitudinal axis extending centrally therethrough and intersecting the upper and lower surfaces. The upper surface comprises a bearing surface for supporting for the drill bit and providing a surface on which the subterranean formation being drilled rubs against the insert without exceeding the compressive strength of the selected formation. The insert is coupled to the blade such that the upper surface thereof extends radially beyond an outer surface of the blade and the lower surface thereof extends radially below the outer surface of the blade.

The force modulation system for a drill bit includes a cutter, a holder, a holder retention device, and a first force member. The cutter fits in the holder, and the holder fits in the drill bit. The holder retention device exerts a holder retention force in a first direction. The first force member exerts a first force in a second direction. The second direction is angled offset to the first direction so as that the cutting profile of the force modulation system is now variable in the second direction, according to the first force. There can also be a second force member to exert a second force in the first direction for more variability of the cutting profile in the first direction. The second force member can be made integral with the first force member.