Abstract: An earth-boring bit comprising a bit body is configured at its upper end for connection into a drillstring. A fixed blade depends axially downwardly from the bit body. An axially extending slot is formed in the bit body adjacent the fixed blade. A bit leg is received and retained in the slot by engagement between the slot and correspondingly shaped bit leg, wherein the bit leg cannot be removed from the slot except by axial movement relative to the bit body. A rolling cutter is secured to the bit leg at its lower extent. A fastener secures the bit leg against movement relative to the bit body and extends through oblong apertures in the bit leg and into the bit body, the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade.

Abstract: An earth-boring bit comprising a bit body is configured at its upper end for connection into a drillstring. A fixed blade depends axially downwardly from the bit body. An axially extending slot is formed in the bit body adjacent the fixed blade. A bit leg is received and retained in the slot by engagement between the slot and correspondingly shaped bit leg, wherein the bit leg cannot be removed from the slot except by axial movement relative to the bit body. A rolling cutter is secured to the bit leg at its lower extent. A fastener secures the bit leg against movement relative to the bit body and extends through oblong apertures in the bit leg and into the bit body, wherein the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade.

Abstract: A hybrid drill bit having both roller cones and fixed blades is disclosed, and a method of drilling. The cutting elements on the fixed blades form a continuous cutting profile from the perimeter of the bit body to the axial center. The roller cone cutting elements overlap with the fixed cutting elements in the nose and shoulder sections of the cutting profile between the axial center and the perimeter. The roller cone cutting elements crush and pre- or partially fracture formation in the confined and highly stressed nose and shoulder sections.

Abstract: A hybrid drill bit having both roller cones and fixed blades is disclosed. The cutting elements on the fixed blades form a continuous cutting profile from the perimeter of the bit body to the axial center. The roller cone cutting elements overlap with the fixed cutting elements in the nose and shoulder sections of the cutting profile between the axial center and the perimeter. The roller cone cutting elements crush and pre-fracture formation in the weak and highly stressed nose and shoulder sections.

Abstract: An earth-boring bit comprising a bit body configured at its upper extent for connection into a drillstring. A selected number of fixed blades extend downward from the bit body and a selected number of rolling cutters are mounted for rotation on the bit body. A plurality of rolling-cutter cutting elements are arranged on each rolling cutter and a plurality of fixed-blade cutting elements are arranged on each fixed blade. The selected number of fixed blades exceeds the selected number of rolling cutters by at least one.

Abstract: An earth-boring bit comprising a bit body configured at its upper extent for connection into a drillstring. A selected number of fixed blades extend downward from the bit body and a selected number of rolling cutters are mounted for rotation on the bit body. A plurality of rolling-cutter cutting elements are arranged on each rolling cutter and a plurality of fixed-blade cutting elements are arranged on each fixed blade. The selected number of fixed blades exceeds the selected number of rolling cutters by at least one.

Abstract: An earth-boring bit comprising a bit body is cofigured at its upper end for connection into a drillstring. A fixed blade depends axially downwardly from the bit body. An axially extending slot is formed in the bit body adjacent the fixed blade. A bit leg is received and retained in the slot by engagement between the slot and correspondingly shaped bit leg, wherein the bit leg cannot be removed from the slot except by axial movement relative to the bit body. A rolling cutter is secured to the bit leg at its lower extent. A fastener secures the bit leg against movement relative to the bit body and extends through oblong apertures in the bit leg and into the bit body, wherein the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade. The slot defines a pair of generally opposed sides connected by a third side, the generally opposed sides being inclined toward one another to define a dovetail that corresponds with the shape of the bit leg.

Abstract: A hybrid drill bit having both roller cones and fixed blades is disclosed. The cutting elements on the fixed blades form a continuous cutting profile from the perimeter of the bit body to the axial center. The roller cone cutting elements overlap with the fixed cutting elements in the nose and shoulder sections of the cutting profile between the axial center and the perimeter. The roller cone cutting elements crush and pre-fracture formation in the weak and highly stressed nose and shoulder sections.

Abstract: A hybrid drill bit having both roller cones and fixed blades is disclosed, and a method of drilling. The cutting elements on the fixed blades form a continuous cutting profile from the perimeter of the bit body to the axial center. The roller cone cutting elements overlap with the fixed cutting elements in the nose and shoulder sections of the cutting profile between the axial center and the perimeter. The roller cone cutting elements crush and pre- or partially fracture formation in the confined and highly stressed nose and shoulder sections.