Numerical and Experimental Study on Belleville Springs as Vibrational Element of Passive Vibration Assisted Rotary Drilling (pVARD) Tool for Drilling Performance Applications

—A novel small-scale laboratory drilling tool, passive Vibration Assisted Rotary Drilling (pVARD) was previously designed and tested through intensive laboratory experiments in the Drilling Technology Laboratory at Memorial University of Newfoundland, Canada. The initial laboratory small-scale pVARD prototype showed promising results in enhancing drilling performance. The current laboratory drilling simulator (LDS) pVARD prototype is designed for wider-range drilling parameters of up to 100 kN of applied Weight on Bit (WOB), 1200 N-m of torque, and up to 1000 rpm of rotational speed. For optimal pVARD configurations and best drilling results, a pVARD operational detail is an important step. The study of this paper concentrates on mechanically designing the pVARD compatible to the LDS, selecting optimal Belleville Springs, conducting experimental and simulation studies to optimize Belleville Springs stacking and pVARD configurations. The mechanical and simulation studies include conducting dynamic and static compression tests as well as a numerical study using simulation on various scenarios of Belleville Spring stacking. The initial mechanical compression tests, numerical study, and subsequent planned intensive drilling experiments can collectively provide important information in optimizing the pVARD fundamentals and can provide pVARD pre-setting and configurations based on the rock types to be drilled and the drilling parameters to be applied for the optimal drilling performance. The results of spring compression tests with the results of drilling performance (planned) can be analyzed based on drilling with and without pVARD. The results can also include the analysis of vibrations produced in both drilling systems recorded by an associated laser sensor.