Study on integrated effect of PDC double cutters

Abstract

This paper studies the integrated effect of double cutters on cutting rock. The rock being cut is subjected to hydrostatic pressure. Double cutters paralleled to each other and separated with a distance are advancing in the same direction and removing rock materials over constant depths of cut. The integrated effect indicates the situation where stresses in rock induced by double cutters can be large enough to even fragment the rock between double cutters. Once this happens, double cutters will have a large cutting area, thus increasing cutting efficiency.A cutting model is built in this paper to study the integrated effect of double cutters. The model calculates coupled stresses and pore pressure in the rock induced by double cutters and predicts cutting forces and MSE. The influences of depths of cut and cutter interval on the integrated effect are discussed. The MSE of double cutters is compared to that of a single cutter under the same cutting condition. Case studies on Indiana limestone show that when the depths of cut are large and the cutter interval is small enough, the integrated effect of double cutters can help reduce the MSE by 5–25 percent. Results in this paper can provide new insights on bit-rock interaction and PDC bit design.