| CPC E21B 10/43 (2013.01) [E21B 10/56 (2013.01)] | 43 Claims |

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1. A drill bit for drilling a borehole in an earthen formation, the bit having a central axis and a cutting direction of rotation, the bit comprising:
a bit body configured to rotate about the axis in the cutting direction of rotation, wherein the bit body includes a bit face;
a blade extending radially along the bit face;
a first cutter element mounted to a cutter-supporting surface of the blade and a second cutter element mounted to the cutter-supporting surface of the blade;
wherein the first cutter element has a central axis and comprises:
a first forward-facing cutting face including a first cutting tip distal the cutter supporting surface and a first planar surface extending radially from the first cutting tip toward the central axis of the first cutter element;
wherein the first planar surface is oriented at a first effective backrake angle measured between the cutter supporting surface and a surface vector of the first planar surface;
wherein the second cutter element has a central axis and comprises:
a second forward-facing cutting face including a second cutting tip distal the cutter supporting surface and a second planar surface extending radially from the second cutting tip toward the central axis of the second cutter element;
wherein the second planar surface is oriented at a second effective backrake angle measured between the cutter supporting surface and a surface vector of the second planar surface;
wherein the second effective backrake angle is greater than the first effective backrake angle;
wherein the first cutting face is completely planar and defined by the first planar surface, and wherein the first cutter element is oriented at a first backrake angle measured between the central axis of the first cutter element and the cutter-supporting surface, and wherein the first effective backrake angle is the same as the first backrake angle;
wherein the second cutting face is non-planar and comprises a plurality of planar surfaces that intersect at distinct edges, wherein the plurality of planar surfaces include the second planar surface.
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