Abstract: Methods of operating earth-boring tools may involve extending a selectively actuatable cutting element outward from a face of the earth-boring tool. A portion of an underlying earth formation may be crushed by a crushing cutting action utilizing the selectively actuatable cutting element in response to extension of the cutting element. The selectively actuatable cutting element may subsequently be retracted. Earth-boring tools may include a selectively actuatable cutting element mounted to a blade, the selectively actuatable cutting element configured to move between a retracted state in which the selectively actuatable cutting element does not engage with an underlying earth formation and an extended state in which the selectively actuatable cutting element engages with the underlying earth formation. The selectively actuatable cutting element may be configured to perform a gouging or crushing cutting action at least upon initial positioning into the extended state.

Abstract: Method of operating earth-boring tools may involve activating a selectively activatable hydraulic fracturing device secured to the earth-boring tool to impact an underlying earth formation with a fluid from the selectively activatable hydraulic fracturing device. A crack may be at least one of initiated or propagated in a portion of the underlying earth formation utilizing the fluid in response to activation of the selectively activatable hydraulic fracturing device. The selectively activatable hydraulic fracturing device may be subsequently deactivated. Earth-boring tools may include a selectively activatable hydraulic fracturing device configured to transition between an activated state in which fluid is permitted to flow through the selectively activatable hydraulic fracturing device to engage with an underlying earth formation and a deactivated state in which fluid does not flow through the selectively activatable hydraulic fracturing device.

Abstract: An earth-boring tool includes a tool body having an aperture therein defining a nozzle port, a nozzle or nozzle assembly disposed in the nozzle port, and a shape memory material disposed adjacent a surface of at least one component of the nozzle or nozzle assembly. The shape memory material retains at least one component of the nozzle or nozzle assembly by a threadless connection. The threadless connection includes mechanical interference between the shape memory material, the at least one component of the nozzle or nozzle assembly, and the tool body or another component of the nozzle or nozzle assembly. The shape memory material is formulated and configured to transform from a first phase and a first shape upon heating and to transform from a second phase and a second shape upon cooling.

Abstract: A method of forming an earth-boring tool includes forming a tool body including at least one inverted cutting element pocket, at least a portion of the at least one inverted cutting element pocket having a profile substantially matching a profile of an actual cutting element to be secured within a cutting element pocket to be formed by subsequently machining the at least one inverted cutting element pocket. Hardfacing material may be applied to portions of the tool body. The actual cutting element pocket is formed by removing material of the tool body within the at least one inverted cutting element pocket subsequent to applying the hardfacing material to portions of the tool body. A cutting element is affixed within the actual cutting element pocket.

Abstract: Methods of forming earth-boring tools include using a plasma spray device to gouge at least one recess through a hardfacing material and into a body. At least a portion of the recess may define a cutting element pocket in which a cutting element may be received and bonded. The recess formed using the plasma spray device optionally may be further machined to form the cutting element pocket. Earth-boring tools are fabricated using such methods.

Abstract: A method of forming an earth-boring tool includes introducing metal into a die, rotating the die to generate centrifugal forces on the metal, and cooling the metal in the rotating die. A rotary drill bit may include a unitary, centrifugally cast bit body including an integral shank, at least one blade, and at least one cutting element on the blade. A rotary drill bit or a roller cone may include a first centrifugally cast material and a second centrifugally cast material. Another rotary drill bit includes a bit body comprising a maraging steel alloy. A method of forming a rotary drill bit may include disposing cutting elements on a rotary drill bit comprising maraging steel and aging the rotary drill bit to form at least one intermetallic precipitate phase. Methods of repairing a rotary drill bit include annealing and aging at least a portion of a rotary drill bit.

Abstract: A method of improving the service life of a drill bit comprises creating a weldment between load bearing portions of the drill bit where the weldment has a preselected root gap greater than about 25 mils and a preselected root face greater than about 25 mils, and where the weldment has a material property greater than the materials being joined.

Abstract: A cutting element for an earth-boring tool includes a body having a longitudinal axis, a generally planar volume of hard material carried by the body, and a sensor affixed to the body. The sensor may be configured to sense at least one of stress and strain. An earth-boring tool includes a cutting element disposed at least partially within a pocket of a body. Methods of forming cutting elements comprise securing a generally planar volume of hard material to a body, attaching a sensor to the body, and configuring the sensor. Methods of forming earth-boring tools comprise forming a cutting element and securing the cutting element within a recess in a body of the earth-boring tool. Methods of forming wellbores comprise rotating an earth-boring tool comprising a cutting element and measuring at least one of stress and strain.

Abstract: An earth-boring tool includes a tool body, at least one cutting element, and a retaining member comprising a shape memory material (e.g., alloy, polymer, etc.) located between a surface of the tool body and a surface of the cutting element. The shape memory material is configured to transform, responsive to application of a stimulus, from a first solid phase to a second solid phase. The retaining member comprises the shape memory material in the second solid phase, and at least partially retains the at least one cutting element adjacent the tool body. The shape memory material may be trained in a first phase to a first shape, and trained in a second phase to a second shape. The retaining member may be at least partially within a cavity in the first phase, then transformed to the second phase to apply a force securing the cutting element to the tool body.

Abstract: A tool for forming or servicing a wellbore includes a first body, a second body, and a retaining member located between a surface of the first body and a surface of the second body. The retaining member at least partially retains the second body with respect to the first body. The retaining member comprises a shape memory material configured to transform, responsive to application of a stimulus, from a first solid phase to a second solid phase. A method of forming a tool for forming or servicing a wellbore includes disposing a retaining member comprising a shape memory material in a space between a first body and a second body and transforming the shape memory material from a first solid phase to a second solid phase by application of a stimulus to cause the retaining member to create a mechanical interference.

Abstract: An earth-boring tool includes a tool body having an aperture therein defining a nozzle port, a nozzle or nozzle assembly disposed in the nozzle port, and a shape memory material disposed adjacent a surface of at least one component of the nozzle or nozzle assembly. The shape memory material retains at least one component of the nozzle or nozzle assembly by a threadless connection. The threadless connection includes mechanical interference between the shape memory material, the at least one component of the nozzle or nozzle assembly, and the tool body or another component of the nozzle or nozzle assembly. The shape memory material is formulated and configured to transform from a first phase and a first shape upon heating and to transform from a second phase and a second shape upon cooling.

Abstract: Method of operating earth-boring tools may involve activating a selectively activatable hydraulic fracturing device secured to the earth-boring tool to impact an underlying earth formation with a fluid from the selectively activatable hydraulic fracturing device. A crack may be at least one of initiated or propagated in a portion of the underlying earth formation utilizing the fluid in response to activation of the selectively activatable hydraulic fracturing device. The selectively activatable hydraulic fracturing device may be subsequently deactivated. Earth-boring tools may include a selectively activatable hydraulic fracturing configured to transition between an activated state in which fluid is permitted to flow through the selectively activatable hydraulic fracturing device to engage with an underlying earth formation and a deactivated state in which fluid does not flow through the selectively activatable hydraulic fracturing device.

Abstract: Methods of operating earth-boring tools may involve extending a selectively actuatable cutting element outward from a face of the earth-boring tool. A portion of an underlying earth formation may be crushed by a crushing cutting action utilizing the selectively actuatable cutting element in response to extension of the cutting element. The selectively actuatable cutting element may subsequently be retracted. Earth-boring tools may include a selectively actuatable cutting element mounted to a blade, the selectively actuatable cutting element configured to move between a retracted state in which the selectively actuatable cutting element does not engage with an underlying earth formation and an extended state in which the selectively actuatable cutting element engages with the underlying earth formation. The selectively actuatable cutting element may be configured to perform a gouging or crushing cutting action at least upon initial positioning into the extended state.

Abstract: Wellbore sensor systems and related methods are disclosed. A wellbore sensor system includes a first sensor node and a second sensor node. The first sensor node is operably coupled to a drill string at a first location. The second sensor node is operably coupled to the drill string at a second location. A method includes taking first sensor readings from the first sensor node relative to a first spatial frame of reference, and taking second sensor readings from the second sensor node relative to a second spatial frame of reference, and using the first sensor readings and the second sensor readings to estimate parameters of a mathematical transform configured to transform the second sensor readings into the first spatial frame of reference. The method also includes transforming the second sensor readings into the first spatial frame of reference with the estimated mathematical transform.

Abstract: A method of forming an earth-boring tool includes forming a tool body including at least one inverted cutting element pocket, at least a portion of the at least one inverted cutting element pocket having a profile substantially matching a profile of an actual cutting element to be secured within a cutting element pocket to be formed by subsequently machining the at least one inverted cutting element pocket. Hardfacing material may be applied to portions of the tool body. The actual cutting element pocket is formed by removing material of the tool body within the at least one inverted cutting element pocket subsequent to applying the hardfacing material to portions of the tool body. A cutting element is affixed within the actual cutting element pocket.

Abstract: Methods of forming earth-boring tools include using a plasma spray device to gouge at least one recess through a hardfacing material and into a body. At least a portion of the recess may define a cutting element pocket in which a cutting element may be received and bonded. The recess formed using the plasma spray device optionally may be further machined to form the cutting element pocket. Earth-boring tools are fabricated using such methods.

Abstract: Methods of forming earth-boring tools include using a plasma spray device to gouge at least one recess through a hardfacing material and into a body. At least a portion of the recess may define a cutting element pocket in which a cutting element may be received and bonded. The recess formed using the plasma spray device optionally may be further machined to form the cutting element pocket. Earth-boring tools are fabricated using such methods.

Abstract: Methods of evaluating performance of simulated drilling operations may involve accepting characteristics of an earth formation. A drill path, a plurality of quality evaluation standards, and selection of a bottom hole assembly (BHA) and at least one earth-boring tool may be accepted. A drilling operation attempting to follow the drill path using the BHA and the drill bit may be simulated. Performance of the BHA and the drill bit in the drilling operation may be evaluated relative to the quality evaluation standards. At least one aspect of the simulated drilling operation may be changed, and simulation of the drilling operation, performance evaluation, and change of the aspects of the drilling operation may be iterated. Performance of each drilling operation may be compared to the other drilling operations, and an improved aspect of a drilling operation may be output relative to the comparative performance of the drilling operations.

Abstract: A cutting element for an earth-boring tool includes a body having a longitudinal axis, a generally planar volume of hard material carried by the body, and a sensor affixed to the body. The sensor may be configured to sense at least one of stress and strain. An earth-boring tool includes a cutting element disposed at least partially within a pocket of a body. Methods of forming cutting elements comprise securing a generally planar volume of hard material to a body, attaching a sensor to the body, and configuring the sensor. Methods of forming earth-boring tools comprise forming a cutting element and securing the cutting element within a recess in a body of the earth-boring tool. Methods of forming wellbores comprise rotating an earth-boring tool comprising a cutting element and measuring at least one of stress and strain.

Abstract: A cutting element for an earth-boring tool includes an elongated body having a longitudinal axis, a generally planar volume of hard material attached to the elongated body, and a sensor affixed to the elongated body. The sensor may be configured to sense at least one of stress and strain. An earth-boring tool includes a cutting element disposed at least partially within a pocket of a body. Methods of forming cutting elements comprise securing a generally planar volume of hard material to an elongated body, attaching a sensor to the elongated body, and configuring the sensor. Methods of forming earth-boring tools comprise forming a cutting element and securing the cutting element within a recess in a body of the earth-boring tool. Methods of forming wellbores comprise rotating an earth-boring tool comprising a cutting element and measuring at least one of stress and strain.