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

Abstract

Abstract. 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 the testing medium showed consistent results with the model, therefore demonstrating 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 predicting finite element models and can identify when the connection will leak according to the standard.