A bottomhole assembly includes: a drill bit operable to vibrate when engaged with a formation and rotated; and a suspension sub including: a stator barrel for connection to a pipe string; a traveler barrel for connection to the drill bit; a slip joint longitudinally coupling the traveler barrel to the stator barrel while allowing movement of the traveler barrel between an extended position and a retracted position; a torsional joint connecting the traveler barrel to the stator barrel at and between the positions; and one or more springs disposed between the stator barrel and the traveler barrel. The suspension is tuned relative to the drill bit to: dampen the vibration of the drill bit when the BHA is rotated at a first angular velocity; and resonate the vibration of the drill bit when the BHA is rotated at a second angular velocity, thereby imparting percussive energy to the drill bit.

Systems and methods for drilling a wellbore include delivering electrical energy to a downhole end of the wellbore. A tapered drill string, with larger drill pipes connected in an up-hole portion with a turbine and an electrical generator and a smaller drill pipes coupled in downhole portion may be used to deliver the electrical power. A turbine and generator may be sufficiently sized to harvest the necessary hydraulic energy and safely operated in a subterranean environment. An electrode carried by the downhole portion of the drill string is electrically coupled to the generator through the downhole portion of the drill string.

Systems and methods for drilling a wellbore include delivering electrical energy to a downhole end of the wellbore. A tapered drill string, with larger drill pipes connected in an up-hole portion with a turbine and an electrical generator and a smaller drill pipes coupled in downhole portion may be used to deliver the electrical power. A turbine and generator may be sufficiently sized to harvest the necessary hydraulic energy and safely operated in a subterranean environment. An electrode carried by the downhole portion of the drill string is electrically coupled to the generator through the downhole portion of the drill string.

The subject disclosure provides for a mechanism implemented with neural networks through machine learning to predict wear and relative performance metrics for performing repairs on drill bits in a next repair cycle, which can improve decision making by drill bit repair model engines, drill bit design, and help reduce the cost of drill bit repairs. The machine learning mechanism includes obtaining drill bit data from different data sources and integrating the drill bit data from each of the data sources into an integrated dataset. The integrated dataset is pre-processed to filter out outliers. The filtered dataset is applied to a neural network to build a machine learning based model and extract features that indicate significant parameters affecting wear. A repair type prediction is determined with the applied machine learning based model and is provided as a signal for facilitating a drill bit operation on a cutter of the drill bit.

The subject disclosure provides for a mechanism implemented with neural networks through machine learning to predict wear and relative performance metrics for performing repairs on drill bits in a next repair cycle, which can improve decision making by drill bit repair model engines, drill bit design, and help reduce the cost of drill bit repairs. The machine learning mechanism includes obtaining drill bit data from different data sources and integrating the drill bit data from each of the data sources into an integrated dataset. The integrated dataset is pre-processed to filter out outliers. The filtered dataset is applied to a neural network to build a machine learning based model and extract features that indicate significant parameters affecting wear. A repair type prediction is determined with the applied machine learning based model and is provided as a signal for facilitating a drill bit operation on a cutter of the drill bit.

A drill bit using track-set depth of cut control elements to provide improved stability is disclosed. A drill bit for drilling a wellbore includes a bit body with a rotational axis extending therethrough. The drill bit further includes a plurality of blades disposed on exterior portions of the bit body. The drill bit includes a first group of track set depth of cut controllers (DOCCs) disposed on exterior portions of a first set of the plurality of blades. The first group of track set DOCCs configured to be placed within a first radial swath of a bit face of the drill bit and configured to provide a first critical depth of cut (CDOC).

Earth-boring tools may comprise rotatable cutting elements rotatably connected to protruding journals, which may be at least partially located within inner bores extending through the rotatable cutting elements. A rotationally leading end of one of the protruding journals may not extend beyond a cutting face of its associated rotatable cutting element. Alternatively, a protruding journal may comprise a chip breaker protruding from a cutting face of a rotatable cutting element. Methods of removing an earth formation may include directing cuttings forward, away from a cutting face of a rotatable cutting element when the cuttings reach an inner bore of the rotatable cutting element, and rotating the rotatable cutting element around a protruding journal at least partially located in the inner bore.

Earth-boring tools may comprise rotatable cutting elements rotatably connected to protruding journals, which may be at least partially located within inner bores extending through the rotatable cutting elements. A rotationally leading end of one of the protruding journals may not extend beyond a cutting face of its associated rotatable cutting element. Alternatively, a protruding journal may comprise a chip breaker protruding from a cutting face of a rotatable cutting element. Methods of removing an earth formation may include directing cuttings forward, away from a cutting face of a rotatable cutting element when the cuttings reach an inner bore of the rotatable cutting element, and rotating the rotatable cutting element around a protruding journal at least partially located in the inner bore.

Roller cutters comprise a diamond-bonded body joined to an infiltration substrate. An extension is joined to the substrate and includes first section having a diameter sized the same as the substrate, and an integral second section having a diameter smaller than the substrate. The extension is joined to the substrate during an HPHT process. The first section has a thickness greater than that of the infiltration substrate. The second section has an axial length greater than the combined thickness of the substrate and the first section. The extension has a strength and/or toughness greater than the substrate as a result of its material composition, e.g., the amount of binder phase material and/or the size of hard phase material. The roller cutter is rotatably disposed within a pocket internal cavity, wherein the pocket is attached to a

Roller cutters comprise a diamond-bonded body joined to an infiltration substrate. An extension is joined to the substrate and includes first section having a diameter sized the same as the substrate, and an integral second section having a diameter smaller than the substrate. The extension is joined to the substrate during an HPHT process. The first section has a thickness greater than that of the infiltration substrate. The second section has an axial length greater than the combined thickness of the substrate and the first section. The extension has a strength and/or toughness greater than the substrate as a result of its material composition, e.g., the amount of binder phase material and/or the size of hard phase material. The roller cutter is rotatably disposed within a pocket internal cavity, wherein the pocket is attached to a