Study On Makeup Torque And Sealing Performance Of Premium Connection In High Pressure Deep Well

Because of the particularity of high pressure deep well,the axial force and internal and external pressure of the connector will be increased.Therefore,it is required proper torque to ensure the sealing performance of the connector.Less torques will makes the shoulder or sealing severe plastic deformation and over torque will result in insufficient contact stress,which caused strength or seal failure.The kind of premium connection three-dimensional finite element model was established with ABAQUS and using the elastic plasticity contact finite element method,considering helix angle,axial force and internal and external pressure analyzes the contact stress and equivalent stress of the premium connection loaded by less,minimum,optimal,maximum,over make-up torque.The results show that,under the action of less torques,sealing surface contact stress is greater than the tube body internal pressure strength,and the connection can realize seal,but the auxiliary seal of the shoulder is lost.Under the action of over torque,the contact stress at the shoulder and the sealing surface is greater than the tube internal pressure strength,the connection can realize sealing,so the optimal torque is best.Under the action of axial tension,premium connection of upper well section of sealing will be failure,when loaded by less torque.And after over torque,the connection can realize seal,but the auxiliary seal of the shoulder is lost.Under the axial pressure and internal and external pressure,the connection can realize seal,but the shoulder auxiliary seal failure when loaded by less torque.Under the over torque,the stress concentration in the screw thread is more serious,and the phenomenon of sticking and thread breaking will arise.Based on the finite element analysis of makeup torque,which gives the assurance at different well depth of premium connections sealed optimal torque and torque range to and provide reference for the selecting of the premium connections.