Method for simulating drilling of roller cone bits and its application to roller cone bit design and performance

A method for balancing lateral forces on a plurality of roller cones on a roller cone drill bit during drilling, comprising:

• (a) calculating, from a geometry of cutting elements on each of the roller cones and an earth formation to be drilled by the bit, a lateral force on each of the cutting elements;
• (b) simulating incrementally rotating the bit and recalculating the lateral force on each of the cutting elements;
• (c) repeating the simulating incrementally rotating and recalculating for a selected number of incremental rotations;
• (d) combining the lateral force on the cutting elements on each one of the roller cones to determine the lateral force on each of the roller cones;
• (e) adjusting at least one bit design parameter and repeating (a) through (d);
• and
• (f) repeating (e) at least until a difference between the lateral force on each of the roller cones is less than the difference between the lateral force on each of the roller cones determined prior to the adjusting the at least one bit design parameter.

A method for modeling interaction between cutting elements on a roller cone bit and subterranean formation during drilling, the method comprising:

• (a) impressing a selected cutting element on a selected earth formation with a selected force to produce a crater on the earth formation;
• (b) recording in a database data representative of the selected cutting element, the selected earth formation, the selected force, and parameters for the crater, the parameters for the crater comprising at least a depth of the crater;
• (c) repeating (a) and (b) a selected number of times with at least one of a different cutting element, a different earth formation, and a different force;
• (d) using the data in the database during a simulation of the roller cone drill bit drilling in the subterranean formation to calculate craters formed when one of the cutting elements on the roller cone bit contacts the subterranean formation.