We are interested in simulating the initial phase of the rock fracturing process of geothermal drilling. In order to simulate the fracture process, we use Particle Flow Code (PFC3D) and synthesize Colorado Red Granite (hereafter "granite"). The discrete nature of PFC allows us to visualize how micro-fractures and cuttings are developed as part of the validation assessment of simulation results. For this study, the granite is synthesized using the Bonded Particle Model (BPM) in PFC3D. Three tests are used to conduct a sensitivity analysis of the micro-parameters associated with the BPM: Triaxial Strength (Triax), Uniaxial Compressive Strength (UCS), and Brazilian Tensile Strength (BTS). A series of visualizations of rock cuttings at different stages will be provided to show the dynamic interaction between the drill bits and the cuttings. A preliminary hypothesis about how the work done by the bits is converted to kinetic and strain energy is discussed. The kinetic energy is associated with the movement of fragmented pieces, and the strain energy is associated with the compression behavior of the bits on the granite sample.