Abstract:The sealability of premium connection is not only related to the sealing structure and materials of connections,but also related to the roughness of sealing surface,and the properties of leakage.The sealing performance analysis of tubing and casing’s premium connections is a complex and difficult problem.The sealing leakage mechanism of premium connections was analyzed on the microscale,and the theoretical model of gasleakage rate through metal seal clearance was established on the microscale.Considering the effect of roughness of the premium connection sealing surface,the mathematical model of gasleakage rate of premium connection was established.The influences of the contact pressure of the sealing surface,the surface roughness and length of the sealing surface on the sealing performance were investigated.The results show that the gas leakage of the premium connection is decreased exponentially with the increase of contact stress and sealing surface length,and increased with the increase of sealing surface roughness.