Studied on Thermal Coupling and Sealing Characteristics of the Subsea Wellhead Connector Metal Seal

The sealing between subsea trees and high pressure wellhead is achieved by the metal seal inside the subsea wellhead connector. In this paper, the sealing performance of the metal seal under the dual role of load and temperature is analyzed. The theoretical analysis of the heat conduction in the sealing part of the subsea wellhead connector is carried out, and the basic equation of heat transfer for transient heat conduction is established, finite element simulation calculations were carried out to obtain the thermal stress of subsea wellhead sealing parts in the process of preload and operating. The results show that as the internal pressure of the subsea wellhead increases, the equivalent contact stress inside the metal seal gradually decreases, and the equivalent stress on the sealing surface is still greater than the initial sealing pressure, ensuring the sealing effect. As the internal pressure of the wellhead increases, the contact stress on the sealing surface of the metal seal increases gradually, with the increases of the temperature, the contact stress increases continuously, when the temperature is too high, the negative impact on the seal is relatively large, resulting in excessive stress inside the seal, which is prone to seal crushing accidents. The temperature effects can be reduced by appropriately reducing the amount of axial preload compression to avoid the metal seal failure.