Numerical Investigation on the Rock Breaking Performance of Special-Shaped PDC Cutters Combination

Abstract

ABSTRACT: The special-shaped polycrystalline diamond compact (PDC) cutter has good rock breaking performance. This paper adopts the finite element method to conduct research on the rock-breaking capabilities of special-shaped PDC cutters. The results show that: with the increase of the spacing between the front row of cutters, the cutting force on the back row of cutters gradually increases and then tends to be stable. The optimum spacing of cutters in the combination of ‘axe-shaped and triple-ridged cutters' is 11mm, the optimum spacing of cutters in the combination of ‘axe-shaped and conical cutters’ is 14mm, the optimum spacing of cutters in the combination of ‘conical and triple-ridged cutters’ is 13mm. In transverse vibration, the combination type of ‘conical and triple-ridged cutters’ has the smallest vibration condition. In the axial vibration, the combination of ‘axe-shaped and conical cutters’ has the lowest vibration. The results of the study can provide a basis for the selection of cutter combinations and the optimal design of drilling tools for PDC drills. 1. INTRODUCTION With the increasing global demand for energy, the exploitation of deep formation oil and gas resources has become one of the focuses of attention in the energy industry (Sun et al., 2013). Deep formation oil and gas resources are rich in reserves and high in quality, however, the characteristics of deep formations such as high rock hardness, strong heterogeneity of formations and high geostress severely limit the drilling efficiency in deep formations (Chen et al., 2024; Guo et al., 2019; Wu et al., 2020). How to efficiently crush rocks in deep hard-to-drill formations and improve rate of penetration has become a key problem to be solved. Conventional rock-breaking techniques are often ineffective when facing deep formations, and it is difficult to meet the industrial demand for efficient, safe, and low-cost drilling (K. Abbas, 2018). Special-shaped Polycrystalline Diamond Compact (PDC) cutter combination rock-breaking technology, as an innovative tool and method, offers a novel solution to overcome the limitations of traditional techniques. Special-shaped PDC cutters not only efficiently crush a wide range of rock types, but also remain stable and wear-resistant over long periods of high-load operation (Che & Ehmann, 2014). In the combined rock-breaking technology of special-shaped PDC cutters, cutters of different shapes and sizes work in concert with each other to maximize crushing efficiency and reduce energy waste.