Intelligent Optimization for a Full-Sized PDC Bit with Composite Percussive Rock Breaking Drilling

Abstract

Intelligent drilling has obtained a lot of attention in mining engineering, oil and gas production, and tunnelling engineering. The optimization of drilling parameters is one of the most important technologies of intelligent drilling, while how to determine the key values to improve the drilling efficiency is still a difficulty. In this paper, we established a composite percussive rock breaking model of a full-size PDC (Polycrystalline Diamond Compact) bit based on the Continuous-Discontinuous Element Method (CDEM). The evolution of rock fragmentation under the action of composite impact is analyzed by the rock breaking volume and the torque applied on the drill bit during drilling. Based on actual construction, two key parameters affecting the process of composite impact rock breaking were selected, axial impact velocity and impact frequency, to further investigate their effect of composite impact rock breaking. The fitting curves obtained from the sensitivity analysis of rock breaking effect under different construction parameters were proposed to guide the intelligent drilling. Furthermore, the construction parameters of a diversion inclined shaft in the #2 construction branch hole of Tiantai Mountain Pumped Storage Power Station in Zhejiang Province were collected, which provides validation data for the proposed optimizing theory of the drilling parameters.