Compression Sealing For Different Surface Topography Research And Optimization Of Sealing Characteristics Of Rubber Cylinder

Compressed-type packers are mainly used in fracturing,acidizing and waterflooding.The rubber casing is the core component to seal the annulus and isolate the production zone.The sealing performance of the rubber casing determines the stratification effect of the reservoir and the production efficiency of the well.In the process of oil well exploitation,due to the complex underground working conditions and harsh environment,the packer seal failure,resulting in layer flow,resulting in production accidents.Therefore,in order to improve the sealing performance of the packer,scholars at home and abroad have optimized its structure,but these optimization schemes often change the structural size of the packer and increase the economic cost.In order to solve the above problems,this paper carries out the research on the sealing performance of the rubber cylinder with different surface morphologies based on the diversified design of the surface morphologies.Based on this,the main research content of this paper is as follows:(1)Based on the functional use and working principle of the packer rubber barrel,this paper studies the sealing mechanism of the packer rubber barrel.According to the sealing mechanism of the packer rubber barrel,multiple rubber materials and the hyperelastic constitutive model are compared and analyzed,and the appropriate material and hyperelastic constitutive model are selected,which provides a theoretical basis for the subsequent analysis of the influence of different working conditions on the sealing performance of the packer rubber barrel and the optimization of the packer rubber barrel.(2)Based on the working mechanism of the rubber cylinder and the principle of fluid pressure penetration,four finite element models of the packer rubber cylinder with different surface morphologies were established.The finite element software ABAQUS was used to analyze the sealing performance of the rubber cylinder under different load conditions.The MISES stress,contact stress,shoulder point value and contact stress between tube and sleeve were studied under the setting load and working pressure difference of the tube with different surface morphologies,and the seal performance rule of the tube with different surface morphologies under different load conditions was obtained,which laid the foundation for the subsequent analysis of the effect of temperature on the seal performance of the tube.(3)On the basis of analyzing the influence of load on the sealing performance of different rubber cylinders,two representative rubber cylinders(ordinary rubber cylinder and semicircular surface)were selected for temperature analysis.Using ABAQUS finite element analysis software,the finite element model of the temperature field of the packer rubber barrel was established,and the sealing performance of the rubber barrel under different temperature conditions was analyzed,and the sealing performance indexes such as the shoulder value,sealing coefficient,compression distance and contact stress between the rubber barrel and casing were studied under the two conditions of constant temperature and dynamic temperature increase.The sealing performance of the cylinder with different surface morphologies was obtained under temperature conditions.(4)Sensitivity analysis was carried out on the parameters of the cylinder with semi-circular surface morphology based on the DOE test design method,and the primary and secondary relationships of structural parameters affecting the sealing performance of the cylinder were analyzed.Parameters that had a great impact on the output response of the cylinder were selected,and appropriate parameters were selected as design variables in combination with the neural network radial basis(RBF)algorithm.The approximate proxy model was established with the maximum contact stress of casing and the maximum MISES stress of rubber tube as output response.Finally,NSGA-II algorithm was used to solve the multi-objective optimization of the structural parameters of the rubber drum,and the optimal structural design parameters were obtained.The optimization results were verified by simulation,and the sealing performance of the rubber drum before and after optimization was compared and analyzed,providing a reference for the structural design and parameter selection of the packer rubber barrel.