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A Method for Evaluating the Rock Breaking Efficiency of Cutters and Optimizing the PDC Cutter Profile—A Study of Igneous Rock Formations in Shunbei Oilfield

The Permian igneous rock in Shunbei Oilfield exhibits high rock strength, which results in a low rate of penetration (ROP) and shortens the cutter’s service life. It is necessary to analyze and evaluate the rock breaking effect of cutters. However, at this stage, the evaluation of the rock breaking effect has been limited to comparing the sizes of the mechanical specific energy (MSE), and the change in the rock breaking efficiency caused by the difference in the shape of the cutters’ surface has not been considered. Therefore, through the establishment of numerical simulation models of a circular cutter, bevel cutter, axe cutter, wedge cutter, and triangular cutter, the evaluation of the rock breaking efficiency of special-shaped cutters was completed. The results show that the triangular cutter and the wedge cutter are suitable for the front row cutter of the polycrystalline diamond compact bit (PDC); the triangular cutter is suitable for drilling into medium–hard formations, the wedge cutter is suitable for drilling into hard formations, and the bevel cutter is suitable for the back row cutter of the PDC, to assist other cutters in the process of rock breaking. The research results can provide the basis for the selection of PDC bit cutters and the design optimization of the bit.