Patent ID: 7861809

Claim:
A rotary drag bit, comprising: a bit body with a face and an axis; at least one blade extending longitudinally and radially outward from the face; a primary cutter row comprising at least one primary cutter, the at least one primary cutter including a cutting surface protruding at least partially from the at least one blade and located to traverse a cutting path upon rotation of the bit body about the axis, and configured to engage a formation upon movement along the cutting path; and a multiple backup cutter group comprising a first trailing cutter row and a second trailing cutter row, the first trailing cutter row comprising at least one cutter having a size smaller than a size of the at least one primary cutter and including a cutting surface protruding at least partially from the at least one blade, the second trailing cutter row comprising at least one cutter having a size smaller than a size of the at least one cutter of the first trailing cutter row and including a cutting surface protruding at least partially from the at least one blade, each cutter of the first and second trailing cutter rows positioned so as to substantially follow the at least one primary cutter along the cutting path upon rotation of the bit body about its axis, and each cutter configured to selectively engage the formation upon movement along the cutting path.