AXISYMMETRICAL MODELING OF DRILLING STRING CONNECTIONS SUBJECT TO INSTALLATION TENSION AND TORQUE

The exploration of oil and gas at great depths requires the use of drill strings composed of connections with highly resistant shoulders, designed to withstand intense and complex loads in hostile environments, where they are prone to the emergence of mechanical weaknesses. To ensure the efficiency and safety of these connections, it is essential to assess their operational limits, particularly the maximum stress they can withstand without exceeding the material’s yield strength. This study employs the Finite Element Method to analyze the stress distribution in a connection subjected to make-up torque and axial tensile load. The methodology involves the axisymmetric modeling of the NC46 connection in ABAQUS®, data processing, and the calculation of the Stress Concentration Factor. The results indicate that the highest stress concentrations occur at the root of the first engaged thread on the pin, aligning with findings from reference studies. Results also show that the preloading effect helps mitigate stress concentration under the applied load.