A model for reliability assessment of sealing performance of the C-shaped metal sealing ring at the outlet of the subsea tubing hanger

The subsea tubing hanger as the core parts in subsea trees provides the only channel to produce oil. The sealing ring of the oil outlet of the tubing hanger plays a crucial role in preventing oil from flowing out and external impurities from entering, which may result in a disastrous consequence. Therefore, it is extremely important to ensure its sealing performance and structural integrity. In this paper, the C-shaped metal sealing ring was decomposed into the cantilever beam model and the simply supported beam model for theoretical analysis, by using its structural axisymmetric characteristics. Combining with the Hertz contact theory, a theoretical model for the contact pressure was derived. The sealing performance was investigated according to key parameters, such as the initial interference (0.08mm–0.375 mm), and internal oil pressure (0 MPa–34.5 MPa). The theoretical and numerical analysis show that the sealing contact pressure is positively correlated with interference and oil pressure. The results indicated that the C-shaped sealing ring has excellent sealing performances and structural integrity in an interference range of 0.1 mm–0.375 mm, and the theoretical model can better reflect the changing trend of the sealing contact pressure, which can provide the significant theoretical basis and practical design reference for enhancing reliability of the tubing hanger for subsea trees in ocean engineering. •An analytical formula for the contact pressure of C-shaped sealing ring was derived.•Sealing performances of the C-shaped ring in operational conditions was obtained.•The analytical and the finite simulation values of contact pressure were compared.