Abstract: A method and system of predicting behavior of a drill bit is disclosed, including generating a mathematical representation of a characteristic of at least one of a plurality of components of a drill bit, the plurality of components including at least one moveable cutter; at least one moveable rubbing element; and at least one moveable gage pad; simulating one or more operating conditions incident on the mathematical representation, and simulating an interaction between the plurality of components and an earth formation; and predicting physical responses of the mathematical representation to the one or more operating conditions.

Abstract: A drill bit includes a bit body; a pad associated with the bit body; and a rate control device coupled to the pad that extends from a bit surface at a first rate and retracts from an extended position to a retracted position at a second rate in response to external force applied onto the pad. The rate control device includes a piston for applying a force on the pad; a biasing member that applies a force on the piston to extend the pad at the first rate; a fluid chamber associated with the piston; and a pressure management device for controlling a fluid pressure within the fluid chamber.

Abstract: A drill bit includes a bit body; a pad associated with the bit body; a rate control device coupled to the pad that extends from a bit surface at a first rate and retracts from an extended position to a retracted position at a second rate in response to external force applied onto the pad. The rate control device includes a piston for applying a force on the pad; a biasing member that applies a force on the piston to extend the pad at the first rate; a fluid chamber associated with the piston; and a pressure management device for controlling a fluid pressure within the fluid chamber.

Abstract: A drill bit and a method of drilling a wellbore utilizing the drill bit is disclosed. The method includes providing a drill bit including a bit body and at least one movable member associated with a lateral extent of the bit body. The method further includes conveying a drill string into a formation, the drill string having the drill bit at the end thereof and drilling the wellbore using the drill string. During drilling, the drill bit can selectively extend the at least one moveable member from the lateral extent of the bit body at a first rate and selectively retract the at least one moveable member to a retracted position at a second rate that is less than the first rate.

Abstract: A method for estimating a location for disposing a tool in a drill tubular having a drill bit includes performing a modal analysis of the drill tubular to determine natural eigenfrequencies and corresponding eigenmodes of torsional oscillations of the model and selecting a predominant natural eigenfrequency and corresponding eigenmode from the determined natural eigenfrequencies and corresponding eigenmodes. The method further includes performing a forced modal analysis of the drill tubular at the predominant eigenfrequency with a force or moment acting on the drill bit to provide a correlation between forced torsional deflection amplitude and position and estimating the position to be within a range of positions wherein a vibration qualification of the tool is greater or equal to the torsional deflection amplitude throughout the range.

Abstract: An apparatus for reducing vibration includes a damping assembly configured to be fixedly attached to a downhole component. The downhole component is configured to rotate within a borehole in an earth formation, and the damping assembly has a damping frequency that is tuned relative to a selected natural vibration frequency of the rotating downhole component to reduce vibration due to component rotation.

Abstract: In one aspect, a method of determining the presence of whirl for a rotating tool is disclosed that in one embodiment includes obtaining measurements (ax) of a parameter relating to the whirl of the tool along a first axis and measurements (ay) of the parameter along a second axis of the tool, determining a first whirl in a time domain for the tool using ax and ay measurements, determining a second whirl rate for the tool in a frequency domain from ax and ay measurements and determining the presence of the whirl from the first whirl rate and second whirl rate. The method further quantifies the whirl of the tool from the first and second whirl rates.

Abstract: A method and system of predicting behavior of a drill bit is disclosed, including generating a mathematical representation of a characteristic of at least one of a plurality of components of a drill bit, the plurality of components including at least one moveable cutter; at least one moveable rubbing element; and at least one moveable gage pad; simulating one or more operating conditions incident on the mathematical representation, and simulating an interaction between the plurality of components and an earth formation; and predicting physical responses of the mathematical representation to the one or more operating conditions.

Abstract: In one aspect, a drill bit is disclosed, including: a bit body; a pad associated with the bit body; a rate control device coupled to the pad that extends from a bit surface at a first rate and retracts from an extended position to a retracted position at a second rate in response to external force applied onto the pad, the rate control device including: a piston for applying a force on the pad; a biasing member that applies a force on the piston to extend the pad at the first rate; a fluid chamber associated with the piston; and a pressure management device for controlling a fluid pressure within the fluid chamber.

Abstract: A drill bit including a bit body and a pad. The pad extends from a retracted position to an extended position from a bit surface at a first rate and retracts from the extended position to a retracted position at a second rate that is less than the first rate.

Abstract: A drill bit and a method of drilling a wellbore utilizing the drill bit is disclosed, including: providing a drill bit including a bit body and at least one movable member associated with a lateral extent of the bit body; conveying a drill string into a formation, the drill string having the drill bit at the end thereof; drilling the wellbore using the drill string; selectively extending the at least one moveable member from the lateral extent of the bit body at a first rate; and selectively retracting the at least one moveable member to a retracted position at a second rate that is less than the first rate.

Abstract: A method of designing an earth-boring rotary drill bit includes designing a bit body and cutting elements of the drill bit such that features of the drill bit other than cutting elements engage and rub against a subterranean formation being drilled by the drill bit at depths-of-cut beyond, but close to, an intended median depth-of-cut, and such that the amount of rubbing area between such features and the formation increases at a relatively rapid rate as the depth-of-cut increases beyond the intended median depth-of-cut. Such methods may be employed to mitigate the occurrence of the “stick-slip” phenomenon during drilling. A method of fabricating a drill bit includes configuring a bit body and cutting elements in accordance with such a design. Earth-boring drill bits include a bit body and cutting elements so configured.

Abstract: In one aspect, a drill bit is disclosed, including: a bit body; a pad associated with the bit body; a rate control device coupled to the pad that extends from a bit surface at a first rate and retracts from an extended position to a retracted position at a second rate in response to external force applied onto the pad, the rate control device including: a piston for applying a force on the pad; a biasing member that applies a force on the piston to extend the pad at the first rate; a fluid chamber associated with the piston; and a pressure management device for controlling a fluid pressure within the fluid chamber.

Abstract: A method for estimating a location for disposing a tool in a drill tubular having a drill bit includes performing a modal analysis of the drill tubular to determine natural eigenfrequencies and corresponding eigenmodes of torsional oscillations of the model and selecting a predominant natural eigenfrequency and corresponding eigenmode from the determined natural eigenfrequencies and corresponding eigenmodes. The method further includes performing a forced modal analysis of the drill tubular at the predominant eigenfrequency with a force or moment acting on the drill bit to provide a correlation between forced torsional deflection amplitude and position and estimating the position to be within a range of positions wherein a vibration qualification of the tool is greater or equal to the torsional deflection amplitude throughout the range.

Abstract: In one aspect, a drill bit is disclosed that in one embodiment includes a bit body and a pad that extends from a retracted position to an extended position from a bit surface at a first rate and retracts from the extended position to a retracted position at a second rate that is less than the first rate.

Abstract: An apparatus for reducing vibration includes: a damping assembly configured to be fixedly attached to a downhole component, the downhole component configured to rotate within a borehole in an earth formation, the damping assembly having a damping frequency that is tuned relative to a selected natural vibration frequency of the rotating downhole component to reduce vibration due to component rotation.

Abstract: In one aspect, a method of determining the presence of whirl for a rotating tool is disclosed that in one embodiment includes obtaining measurements (ax) of a parameter relating to the whirl of the tool along a first axis and measurements (ay) of the parameter along a second axis of the tool, determining a first whirl in a time domain for the tool using ax and ay measurements, determining a second whirl rate for the tool in a frequency domain from ax and ay measurements and determining the presence of the whirl from the first whirl rate and second whirl rate. The method further quantifies the whirl of the tool from the first and second whirl rates.