Study on rock reaction force depending on PDC cutter placement

The article focuses on the problem of polycrystalline diamond cutter (PDC) cutters' overlapping influence on rock reaction force. This study proposed a static force balance model, based on the model of Wojtanowicz and Kuru (1993 Wojtanowicz, A.K.; Kuru, E. (1993) Mathematical modeling of PDC bit drilling process based on a single-cutter mechanics. Journal of Energy Resources Technology-Transactions of the ASME, 115(4): 247–256.Crossref], Web of Science ®] , Google Scholar]). The innovation of this model is considering two types of friction forces, acting on the contact frontal surface and the lateral surface of a PDC cutter, respectively. Additionally, the proposed model assumes a rock reaction force direction not orthogonal to the contact surface of a cutter but parallel to the crack propagation direction and similar to the rock heterogeneity direction.

Numerical study was provided for a new and a worn PDC cutter to define a rock reaction force depending on options of adjacent cutters' placement (cutters' shape, cutter sizes, bake rake angle, side rake angle, etc.). Two main tendencies were observed: increasing of lateral plot of a cutter decreases rock reaction force, and deviation between directions of cutting force and crack propagation is an extremely significant factor and affects rock reaction force magnitude.