DRILLING SYSTEMS AND HYBRID DRILL BITS FOR DRILLING IN SUBTERRANEAN FORMATION AND METHODS RELATING THERETO Russian patent published in 2018 - IPC E21B10/14 E21B10/20 

FIELD: soil or rock drilling; mining.

SUBSTANCE: group of inventions relates to drill bits and a method for drilling a wellbore in a subterranean formation. Drill bit comprises a bit body having a bit axis, a first end configured to be coupled to a lower end of a drill string, and a second end configured to engage the subterranean formation. Bit body includes a plurality of legs circumferentially arranged about the bit axis, wherein each leg has a lower section extending axially from the second end of the bit, and wherein each lower section has a leading surface relative to a direction of bit rotation about the bit axis and a trailing surface relative to the direction of bit rotation. Drill bit also comprises a plurality of rolling cone cutters, wherein each rolling cone cutter is rotatably mounted to the lower section of one of the legs and positioned along the leading surface of the corresponding leg. Each cone cutter has a cone axis of rotation that is radially spaced from the bit axis and is substantially perpendicular to a plane containing the bit axis. Drill bit also comprises a plurality of circumferentially-spaced fixed blades. Each fixed blade extends radially outward from the lower section of each leg. Each fixed blade has a radially outer formation-facing surface circumferentially arranged between the leading surface and the trailing surface of the corresponding leg. Each cone cutter includes a first plurality of cutter elements arranged in a first circumferential row extending about the corresponding cone axis of rotation, and each of the first plurality of cutter elements includes a planar cutting face that is configured to engage and shear the subterranean formation, when the bit body is rotated about the bit axis in the direction of bit rotation. Drill bit further comprises a second plurality of cutter elements mounted on the surface of each fixed blade facing the formation and configured to engage with the formation and shear said formation when the bit body rotates about the axis of the bit in the cutting direction.

EFFECT: technical result reduction of the number of drill string tips before the completion of the wellbore.

24 cl, 13 dwg