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.

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.

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.

A drill assembly has a stinger with downward oriented cups including an upper cup and a lower cup. The cups create a loss zone therebetween in a downhole environment. The downhole environment can be a shaft of a well. The loss zone can be filled with cement to plug the shaft. The downward oriented cups isolate the loss zone from the shaft and minimize the hydrostatic pressure above the upper cup.

A drill assembly has a stinger with downward oriented cups including an upper cup and a lower cup. The cups create a loss zone therebetween in a downhole environment. The downhole environment can be a shaft of a well. The loss zone can be filled with cement to plug the shaft. The downward oriented cups isolate the loss zone from the shaft and minimize the hydrostatic pressure above the upper cup.

A drill bit comprises a bit body having a longitudinal axis and a blade extending radially outward from the longitudinal axis along a face region and axially along a gauge region. A gauge region includes a cutting element located proximate to an uphole edge of the blade in the gauge region. A remainder of the gauge region is free of cutting elements mounted thereon. A method of drilling a borehole comprises rotating the bit about the longitudinal axis, engaging a formation with cutting elements mounted to the face region, and increasing a lateral force applied substantially perpendicular to the longitudinal axis such that the cutting element engages the formation and such that side cutting exhibited by the tool is initially minimal and substantially constant and subsequently increases in a substantially linear manner with increasing lateral force.

The invention provides a bit breaker comprising a generally flat plate that defines two arms and a base leg. The two arms project respectively from opposed ends of the base leg. The bit breaker has a generally rectangular pipe slot located between the two arms. The bit breaker includes a jaw mounted on one of the arms so as to be removable therefrom when damaged and thereafter replaced with a new jaw. The jaw defines a working surface located on a side of the pipe slot. In some embodiments, the bit breaker further comprises a security plate attached to the generally flat plate so as to define a mount space between the generally flat plate and the security plate. The jaw is received in the mount space such that the jaw has limited freedom of movement relative to both the generally flat plate and the security plate.

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.

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.

A drill assembly has a stinger with downward oriented cups including an upper cup and a lower cup. The cups create a loss zone therebetween in a downhole environment. The downhole environment can be a shaft of a well. The loss zone can be filled with cement to plug the shaft. The downward oriented cups isolate the loss zone from the shaft and minimize the hydrostatic pressure above the upper cup.