Analysis On The Integrity Of Premium Connection In High Temperature Gas Wells And The Study Of Make-up Experiment

In the high temperature,high pressure and directional wells,the tubing string is subjected to large temperature load,axial load,internal and external pressure and bending load,in which the tubing connection is the weakest part of the whole tubing string.In order to avoid the problem of sealing or connection failure caused by the stress concentration of premium connection,the integrity of premium connection in high temperature gas wells is studied in this paper.In order to study the influence of temperature load on the integrity of premium connection,firstly,the elastic-plastic finite element method is used to establish the three-dimensional finite element model of premium connection.Considering the effect of the helix ascending angle of screw thread on the anti-torque,the method of controlling the corner is used to simulate the make-up process.Secondly,considering the temperature load,the integrity of the premium connection under complex load is studied.At the same time,the influence of temperature load on the integrity of the bending section of the premium connection is studied.The premium connection is tested by the micro-tooth hydraulic power clamp,and the make-up performance of three kinds of torque on the premium connection is analyzed.Moreover,this paper studied the effects of different temperature act on the integrity of premium connection after make-up.The results show that,under complex load,premium connection is in good performance and the plastic deformation does not occur within the temperature changes,the temperature changing affect the connection integrity a lot ranging form 50℃ to 150℃.The distribution of Mises stress and contact pressure of the premium connection of the bending section at different temperature is uneven,one side of the connection is pulled and the other side is pressed,compression side severe stress concentration can easily produce thread gluing,the sealing surface and the shoulder contact pressure of the tensile side is small,the sealing performance is poor.The make-up experiment tests three-dimensional finite element method to simulate the validity of the make-up of the premium connection.After make-up by three kinds of torque the sealing surface and shoulder near the tip of the premium connection has a higher contact pressure under different temperature,meanwhile the sealing surface near the tipand the shoulder appeared plastic deformation,and the degree of plastic deformation increases with the increasing of temperature.The influence of temperature load on the integrity of premium connection is studied,which provides a reference for the safe use of premium connection in high temperature gas wells.