Abstract: Disclosed is method for designing a fixed cutter drill bit comprising: (a) defining initial primary placement parameters for primary cutter elements; (b) repeatedly: selecting back up placement parameters for back up cutter elements; applying to a simulated formation a bit design having the combination of the defined initial primary placement parameters and the selected back up placement parameters; using the combination in the simulation and generating a value representative of a first design criteria of interest (such as resultant force on a cutter element, total out-of-balance force on the bit, resistance to slip stick, and resistance to bit vibration); comparing the generated value to a first predetermined acceptable value.

Abstract: A drill bit for drilling a borehole in earthen formations comprises a bit body having a central bit axis, a first end adapted to be connected to a drillstring, and a second end opposite the first end. In addition, the bit comprises a pilot bit extending from the second end of the bit body. Further, the bit comprises a reamer section extending radially from the bit body and axially positioned between the first end of the bit body and the pilot bit. The reamer section comprises a rolling cone cutter rotatably mounted to a journal shaft extending from the bit body. Moreover, the rolling cone cutter has a cone axis of rotation, a backface proximal the bit body, and a nose opposite the backface and distal the bit body.