Characterization of Carbonate Rock Fragmentation Under Torsional Impact Loading

ABSTRACT: In order to study the influence of torsional impact technology on rock stress response, cutting force and other parameters of carbonate rock under different impact amplitude and impact frequency, the crushing test of carbonate rock was carried out by using the method of torsional impact assisted PDC bit, and the single-tooth rock crushing model under torsional impact was established, and the influence of different impact parameters on crushing efficiency was analyzed. The results show that under the condition of reasonable selection of torsional impact frequency and amplitude, torsional impact technology can effectively reduce the rock breaking torque and improve the rock breaking efficiency. The peak Mises stress increases by 42.3%,and the average cutting force of 1.5 times the amplitude is reduced by 10.6%. The research results are expected to provide a scientific basis for accelerating the drilling rate of carbonate rocks. INTRODUCTION Geothermal energy, as one of the renewable energy sources, is a resource that can provide low-carbon, renewable loads for the production of electricity and heat, and has great potential for development. Although geothermal energy resources have their unique advantages, taking carbonate reservoirs as an example, the deep geothermal resource reservoirs are characterized by low permeability, high abrasiveness and high hardness, which makes the development of geothermal resources relatively difficult. Geothermal drilling, as the most basic and important part of geothermal development, has been attracting much attention. Expensive drilling equipment, experienced drilling experts and strong financial support are necessary for geothermal energy development. Therefore, reducing the number of drilling days and improving the drilling efficiency are the main ways to achieve the goal of commercializing geothermal energy. Currently, the conventional rotary drilling method is commonly used for drilling wells in carbonate formations, but the low rock crushing efficiency and severe wear and tear of the drill bit of this drilling method, which in turn leads to long drilling cycles and high drilling costs, have severely restricted the large-scale development of geothermal energy in carbonate formations.