The Mechanical Behavior Numerical Simulation And Revise Of Expandable Packer

When the working conditions are complex,the sealing performance and strength of the packer rubber can not still meet the requirement.Therefore,the numerical simulation of the mechanical behavior of the expandable packer is carried out in this paper.The problems reflected in the various stages of the force are analyzed.Then the rubber was studied from the material and structure.And the sealing performance of the single sealing element and the combined sealing element are analyzed and compared.In this paper,the K344 packer is used as the object,and the elastic theory and the theory of large deformation theory are used to analyze the stress of the packer in two stages,the first stage is after the expansion of the rubber and before contact with the casing,the second stage is after contact with the casing,the characteristics of each stage are obtained.The K344 local model is established by using finite element software(Including central tube,upper and lower rubber cylinder seat and casing).The working process is simulated,and the stress nephogram of each stage is obtained.The results show that when the packer is in the internal pressure of 20 MPa,the stress level of the upper and lower rubber cylinder seat and the central pipe joint is the highest,and the maximum Mises stress is 66.19 MPa.In the rubber tube,the middle part of the stress changes slowly,but near the ends should be up to 18.05 MPa,and the shoulder deformate biggest,its shear strain reached 0.8.According to the stress characteristics of rubber barrel reflected in the packer when,in the modeling of rubber cylinder structure was improved,the change of packer rubber structure parameters(thickness,height,friction coefficient,shoulder angle,add steel cord)with finite element analysis.After comparing and analyzing,it is found that under the same external conditions,the contact stress of the rubber cylinder decreases with the increase of the thickness of the rubber tube,the sealing performance is decreased,the packer design should choose a suitable rubber thickness to ensure sufficient contact stress,so as to achieve a good sealing performance.With the change of the shoulder angle of the packer,the maximum stress on the rubber cylinder is not very different,and the maximum stress at the angle of 15 degrees is higher than the stress at 30 and 45 degrees,so it is recommended that the shoulder angle be 15 degrees,it is not only beneficial to weaken the shoulder of the prominent degree,also can meet the strength requirement.In the modeling of rubber material was improved by adding 1-3 layer of steel cord in the rubber cylinder in the finite element analysis was carried out by sealing process,material reinforcement measures are obtained.In this paper,the sealing performance of a single sealing element and a combined sealing element is analyzed,expansion type sealing elements and expansion type and compression type sealing elements are analyzed by finite element analysis,by comparing the data we can see that the use of combined sealing element,not only reduces the packer packer force,and the bearing capacity is higher than the single element to seal type,the sealing effect is better.