Abstract: Downhole drilling tools designed and manufactured to minimize or reduce imbalance forces and wear by disposing cutting elements in cutter groups and cutter sets in a level of force balance and by placing impact and/or wear resistant cutters on blades subject to high impact forces and/or large loadings. Manufacturing costs may be reduced by placing inexpensive cutters on blades not subject to high impact forces and/or loadings. Some embodiments comprise designing downhole tools with combinations of thicker blades to receive high impact forces and/or loadings with thinner blades. Some embodiments comprise designing downhole drilling tools with optimized fluid-flow properties. Designing methods may comprise performing simulations on a designed tool, evaluating respective forces acting on cutters during simulated engagement with a downhole (uniform and transitional) and/or evaluating wear on cutters and bit, and/or CFD simulations to evaluate fluid-flow optimization on a tool.

Abstract: The present disclosure relates to fixed-cutter drill bits with track-set primary cutters and backup cutters, methods of designing such bits, systems for implementing such methods, and systems for using such fixed-cutter drill bits to drill a wellbore in a geological formation.

Abstract: Methods for simulating a downhole drilling operation include estimating the geometry, i.e., the shape, size of cuttings or rock chips generated by engagement of a drill bit with a geologic formation. Each cutting element on the drill bit may produce rock chips of different geometry, and the geometry of rock chips generated by a particular cutting element may change over a predetermined interval. The geometry and other properties rock chips predicted for an interval may be recorded, and a distribution may be calculated based on categorizing each of the predicted rock chips into predefined categories and determining the relative number of rock chips in each category. The distribution may be useful in drill bit design, determining required mud flow characteristics for a drilling operation, and facilitating rotation of a drill string by preventing undesirable interactions of the rock chips with the drill bit, a drill pipe or other downhole equipment.

Abstract: A method for bit-rock interaction modeling includes selecting a parameter for a drill bit model. The parameter includes a geometrical factor of a cutter represented in the drill bit model. The method further includes dynamically adjusting the drill bit model to a displaced position, updating a shape of a wellbore model formed by the displaced position of the drill bit model, and determining local and initial forces on the drill bit model based on the shape of the wellbore model and the parameter for the drill bit model. The method further includes determining, by a processor, at least one coefficient for a bit matrix based on the local force and the initial force on the drill bit model; and storing the bit matrix in a memory, wherein the bit matrix is indicative of an interaction between a drill bit represented by the drill bit model and a formation substrate.

Abstract: A multi-layer downhole drilling tool designed for directional and horizontal drilling is disclosed. The drilling tool includes a bit body including a rotational axis extending therethrough. A plurality of primary blades are disposed on exterior portions of the bit body and a plurality of secondary blades are disposed on exterior portions of the bit body between the primary blades. The drilling tool further includes a plurality of first-layer cutting elements disposed on exterior portions of the primary blades and a plurality of second-layer cutting elements disposed on exterior portions of the secondary blades. The second-layer cutting elements are track set with the first-layer cutting elements in an opposite track set configuration.

Abstract: A method of designing a drill bit is disclosed. The method includes determining a location of a bit coordinate system in a wellbore coordinate system and generating a bit profile based on an angular coordinate around a wellbore axis of a wellbore and the location of the bit coordinate system. The bit profile is based on a cutting edge of a first cutting element on an exterior portion of a first blade. The method also includes determining a cutting layer volume based on the bit profile and identifying a weak zone based on the cutting layer volume being less than a predefined minimum cutting layer volume. The method includes determining a location for a second cutting element on the exterior portion of a second blade based on the weak zone.

Abstract: A drill bit cutter having a shaped cutting element is disclosed. The cutter includes a substrate having a fixed portion, and a rotating portion rotatably attached to the fixed portion. The cutter also includes a cutting element secured to the rotating portion of the substrate, the cutting element having a non-circular cross-section in a plane perpendicular to a cutter axis of the rotating cutting element, the cross-section having a radially symmetric shape.

Abstract: A method of designing a drill bit is disclosed. The method includes determining a location of a bit coordinate system in a wellbore coordinate system and generating a bit profile based on an angular coordinate around a wellbore axis of a wellbore and the location of the bit coordinate system. The bit profile is based on a cutting edge of a first cutting element on an exterior portion of a first blade. The method also includes determining a cutting layer volume based on the bit profile and identifying a weak zone based on the cutting layer volume being less than a predefined minimum cutting layer volume. The method includes determining a location for a second cutting element on the exterior portion of a second blade based on the weak zone.

Abstract: A method of designing a downhole drilling tool may include generating a three dimensional (3D) downhole drilling tool model and simulating engagement of the drilling tool model with a 3D model of a borehole bottom. First and second cutting zones of first and second cutting elements may be determined based on areas of the first and second cutting elements that engage the borehole bottom, where the first and second cutting zones respectively have first and second cutting zone shapes. First and second cutting forces for the first and second cutting elements may be calculated based on the respective first and second cutting zone shapes. A drilling efficiency of the drilling tool model may be modeled based at least on the first cutting force and the second cutting force and a design parameter of the drilling tool model may be modified based on the drilling efficiency of the drilling tool model.

Abstract: In accordance with some embodiments of the present disclosure, a method of designing a drill bit comprises determining placements on a drill bit for a plurality of cutting elements at a plurality of radial coordinates of the drill bit. The method further comprises determining a substrate-based critical depth of cut for a substrate of each cutting element and generating a substrate-based critical depth of cut control curve based on the substrate-based critical depth of cut at each radial coordinate. The method also comprises comparing the substrate-based critical depth of cut control curve and the threshold critical depth of cut control curve and adjusting a drill bit design parameter if the substrate-based critical depth of cut control curve is less than or equal to the threshold critical depth of cut control curve at a radial coordinate.

Abstract: A downhole drilling tool designed for drilling a wellbore is disclosed. The drilling tool includes a bit body, and a first plurality of blades and a second plurality of blades on exterior portions of the bit body. A first group of cutting elements is located on exterior portions of the first plurality of blades. A second group of cutting elements is located on the second plurality of blades and under-exposed with respect to the first group of cutting elements. The first and second plurality of blades and the first group and second groups of cutting elements cooperate with each other to form a composite bit face profile such that each respective group of at least three neighbor cutting elements on the composite bit face profile is force balanced with respect to each other.

Abstract: A multi-layer downhole drilling tool designed for drilling a wellbore including a plurality of formations is disclosed. The drilling tool includes a bit body and a plurality of primary blades and secondary blades with respective leading surfaces on exterior portions of the bit body. The drilling tool further includes a plurality of first layer cutting elements and second layer cutting elements located on the leading surfaces of the primary blades and secondary blades, respectively. Each second layer cutting element is under-exposed with respect to the corresponding first layer cutting element. The amount of under-exposure is selected according to each second layer cutting element having an initial critical depth of cut greater than an actual depth of cut for a first drilling distance and a critical depth of cut equal to zero at a target drilling depth.

Abstract: A downhole drilling tool designed for drilling a wellbore is disclosed. The drilling tool includes a bit body and a first plurality of blades and a second plurality of blades on exterior portions of the bit body. A first group of track-set cutting elements is on exterior portions of the first plurality of blades and a second group of track-set cutting elements is on the second plurality of blades. The first and second plurality of blades and the first group and second group of track-set cutting elements cooperate with each other to form a composite bit face profile such that each respective group of at least three neighbor cutting elements on the composite bite face profile is force balanced with respect to each other.

Abstract: A multi-layer downhole drilling tool designed for drilling a wellbore including a plurality of formations includes a bit body and a plurality of primary blades and secondary blades with respective leading surfaces on exterior portions of the bit body. The drilling tool further includes a plurality of first layer cutting elements and second layer cutting elements located on the leading surfaces of the primary blades and secondary blades, respectively. Each second layer cutting element is under-exposed with respect to the corresponding first layer cutting element. The amount of under-exposure is selected according to each second layer cutting element having an initial critical depth of cut greater than an actual depth of cut for a first drilling distance and a critical depth of cut equal to zero at a target drilling depth.

Abstract: A drill bit includes a bit body having cutters and a generally cylindrical rolling element secured thereon. The rolling element protrudes from the bit body to engage a geologic formation. The location and orientation of the rolling element may be selected such that an outer surface of the rolling element maintains multiple points of contact with the geologic formation to balance the operational forces acting thereon for a desired minimum depth of cut. A moment acting on the rolling element may be minimized to thereby prevent damage to the drill bit. A method for configuring the rolling element may include calculating a critical depth of cut for each point along a radial interval defined by the cylindrical body, changing a design variable, and recalculating the critical depth of cut until at least three contact points exist along the rolling element for a desired minimum depth of cut for the interval.

Abstract: A well tool can include a cutter with at least one cutting layer and a substrate, the cutting layer having a leading face, and the substrate partially overlying the leading face. A method of constructing a well tool can include forming a cutter by at least partially embedding at least one cutting layer in a substrate, and securing the cutter to the well tool. A drill bit can include a drill bit blade, and a cutter secured on the drill bit blade, the cutter including a substrate and at least one cutting layer embedded in the substrate, the substrate overlying leading and trailing faces of the cutting layer.

Abstract: In accordance with some embodiments of the present disclosure, a method of configuring depth of cut controllers (DOCCs) of a drill bit comprises determining a primary depth of cut for a first radial swath. The first radial swath is associated with a first area of the bit face. The method further comprises configuring a primary DOCC for placement on the bit face within the first radial swath based on the primary depth of cut. In addition, the method comprises determining a back-up depth of cut for a second radial swath. The second radial swath is associated with a second area of the bit face that overlaps the first area of the bit face associated with the first radial swath. The method further comprises configuring a back-up DOCC for placement on the bit face within the second radial swath based on the back-up depth of cut.

Abstract: Downhole drilling tools designed and manufactured to minimize or reduce imbalance forces and wear by disposing cutting elements in cutter groups and cutter sets in a level of force balance and by placing impact and/or wear resistant cutters on blades subject to high impact forces and/or large loadings. Manufacturing costs may be reduced by placing inexpensive cutters on blades not subject to high impact forces and/or loadings. Some embodiments comprise designing downhole tools with combinations of thicker blades to receive high impact forces and/or loadings with thinner blades. Some embodiments comprise designing downhole drilling tools with optimized fluid-flow properties. Designing methods may comprise performing simulations on a designed tool, evaluating respective forces acting on cutters during simulated engagement with a downhole (uniform and transitional) and/or evaluating wear on cutters and bit, and/or CFD simulations to evaluate fluid-flow optimization on a tool.

Abstract: A multi-layer downhole drilling tool designed for drilling a wellbore including a plurality of formations is disclosed. The drilling tool includes a bit body including a rotational axis extending therethrough. A plurality of blades are disposed on exterior portions of the bit body. A plurality of primary cutting elements and a plurality of back-up cutting elements are disposed on exterior portions of the plurality of blades. The back-up cutting elements are track set with corresponding primary cutting elements, and each back-up cutting element is disposed on a different blade than the corresponding primary cutting element.

Abstract: A drill bit includes a bit body having cutters and a generally cylindrical rolling element secured thereon. The rolling element protrudes from the bit body to engage a geologic formation. The location and orientation of the rolling element may be selected such that an outer surface of the rolling element maintains multiple points of contact with the geologic formation to balance the operational forces acting thereon for a desired minimum depth of cut. A moment acting on the rolling element may be minimized to thereby prevent damage to the drill bit. A method for configuring the rolling element may include calculating a critical depth of cut for each point along a radial interval defined by the cylindrical body, changing a design variable, and recalculating the critical depth of cut until at least three contact points exist along the rolling element for a desired minimum depth of cut for the interval.