Numerical and Experimental Assessments on the Performance of Gas-Tight Oilfield Tubular Connections under Cyclic Downhole Service Conditions

In this work, a finite element model was developed and a series of experimental tests were conducted on a gas tight tubular connection to investigate the sealing mechanism and the integrity of the entire connection under the combined effects of the make-up process and high cyclic loading, simulating real-world field conditions. Findings of both numerical and experimental assessments show that the most critical condition impacting the sealing performance of a gas-tight connection subjected to cyclic loading is tensile loading with internal pressure. Full-scale experiments with water and nitrogen as testing medium showed consistent results with the model, what speaks of the validity of the model. Finally, three sealability indicators were found based on tuning them with the full-scale results, this gives a powerful tool for having predicting finite element models and can identify when the connection will leak according to the standard.