Non-uniform roller cone

A drill bit comprising:

• a bit body having a rotational axis;
• a first fixed blade fixed relative to the bit body with a first plurality of fixed blade cutting elements affixed to the first fixed blade;
• a second fixed blade fixed relative to the bit body with a second plurality of fixed blade cutting elements affixed to the second fixed blade;
• a third fixed blade fixed relative to the bit body with a third plurality of fixed blade cutting elements affixed to the third fixed blade;
• and
• a roller cone supported by the bit body, the roller cone including:
• an innermost region having roller cone cutting elements arranged thereon, wherein the roller cone cutting elements of the innermost region are closest to the rotational axis,
• an inner first central region having roller cone cutting elements arranged thereon, wherein a first transition from the innermost region to the inner first central region corresponds to a radially innermost fixed cutting element of the first plurality of fixed blade cutting elements,
• an outer first central region having roller cone cutting elements arranged thereon, wherein a second transition from the inner first central region to the outer first central region corresponds to a radially innermost fixed cutting element of the second plurality of fixed blade cutting elements, and
• a second central region having roller cone cutting elements arranged thereon, wherein a third transition from the outer first central region to the second central region corresponds to a radially innermost fixed cutting element of the third plurality of fixed blade cutting elements,
• wherein a cutting element density of at least one of the inner first central region, the outer first central region, and the second central region is no less than 75% greater than the cutting element density of another of the inner first central region, the outer first central region, and the second central region.

A drill bit comprising:

• a bit body having a rotational axis;
• a first fixed blade fixed relative to the bit body with a first plurality of fixed blade cutting elements affixed to the first fixed blade;
• a second fixed blade fixed relative to the bit body with a second plurality of fixed blade cutting elements affixed to the second fixed blade;
• and
• a roller cone supported by the bit body, the roller cone including:
• an innermost region having roller cone cutting elements arranged thereon, wherein the roller cone cutting elements of the innermost region are closest to the rotational axis,
• a first central region having roller cone cutting elements arranged thereon, wherein a first transition from the innermost region to the first central region corresponds to a radially innermost fixed cutting element of the first plurality of fixed blade cutting elements,
• a second central region having roller cone cutting elements arranged thereon, wherein a second transition from the first central region to the second central region corresponds to a radially innermost fixed cutting element of the second plurality of fixed blade cutting elements, and
• an outermost region having roller cone cutting elements arranged thereon, wherein the outermost region has a radial length no less than 10% of a radius of the drill bit relative to the rotational axis,
• wherein a cutting element density of the second central region is no less than 75% greater than the cutting element density of the first central region.