The Analysis On Thermal Coupling And The Study On Sealing Characteristics Of VX Metal Gasket

The seal between subsea trees and high pressure wellhead is achieved by the VX metal gasket inside the connector.It is one of the key sealing parts to the subsea trees.In this paper,the sealing technology of connector in the high pressure wellhead is studied.Sealing performance of VX metal gasket under the dual role of load and temperature is analyzed.This paper gives the theory analysis of heat conduction on the part of subsea wellhead,and establishes the basic equations of transient heat conduction,and introduces the finite element method and the direct integral method of transient heat conduction.Paper also introduces the thermodynamic coupling finite element method of subsea wellhead sealing parts,and establishes the energy conservation equation.Combining the working principle of the VX metal gasket,the paper deduces the formula of pre-tightening contact stress and operation contact stress,and deduces the formula of stress checking of the gasket.Besides,the paper qualitative analyzes the impact of sealing performance of the gasket by preloaded compressed volume,inner pressure,tight coefficient and contact state.Subsea wellhead sealing parts are analyzed in numerical simulation.Paper shows the distribution of temperature field and thermal stress of subsea wellhead sealing parts and stress distribution of VX metal sealing gasket in the process of preload and operating.The paper also provides the numerical simulation analysis of thermal coupling.The results show that,temperature field has influence on sealing performance of the gasket.It needs to avoid the situation of overheating on the wellhead.And it provides a very valuable reference for the study of wellhead seal at high temperature and pressure.