Design And Sealing Characteristics Of A New Downhole Hydraulic Packer

As the key equipment in petroleum exploitation,the excellent performance of packer directly affects the overall efficiency of petroleum exploitation.With the development of the global economy and the continuous improvement of new mining technology,the technical means of fracturing,plugging and mining of oil Wells are also transferred to the deeper stratum for development,which brings more severe mining environment.This makes it difficult for traditional packers to operate in high-temperature and high-pressure environments.Based on this,a new type of hydraulic packer is designed in this paper.When it is working,the rubber cylinder is slowly pushed to meet the needs of the packer rubber cylinder in the downhole and the outer wall of the pipe for pressing or stretching,so as to realize the coordinated operation control of the packer opening and closing.In the working process,the problem of setting failure caused by excessive or insufficient compression of the rubber cylinder due to too large or too small setting force can be reduced.Traditional packers bounce back through the elasticity of rubber in the process of unsealing.However,if the packer is kept downhole for a long time,the rubber cylinder of the packer will be damaged.As a result,the packer cannot bounce back depending on its elasticity,and even the rubber cylinder and the pipe wall will be stuck,affecting the overall unsealing effect and the actual production efficiency.The new downhole hydraulic packer uses hydraulic pressure to stretch the rubber casing portion of the packer during unpacking,separating the rubber casing from the downhole wall and ultimately removing the entire packer.In view of the above problems,this paper takes the hydraulic packer as the research object,combines the basic theoretical research,design calculation and simulation theory,and develops a new type of downhole hydraulic packer which uses the micro-hydraulic system to control the packer opening and closing coordinated action.Compared with the traditional packer set by mechanical force,hydraulic setting has the advantages of simple structure,stable motion,balanced thrust,controllable motion displacement,and stretching and retracting the cartridge to reduce the failure of the cartridge during the process of unsealing.The structure of the rubber barrel part of the packer is designed,and the finite element simulation analysis is used to study whether the rubber barrel has anti-surge structure,different height,different thickness,different dip Angle and so on.The design is suitable for the hydraulic packer rubber barrel structure under the conditions of downhole high temperature and high pressure.Finally,it is concluded that there is an anti-outburst structure;The height of the rubber cylinder is L=85mm-70mm-85mm;The thickness of the rubber cylinder is 16.5mm;When the inclination Angle is 45°,the sealing comprehensive performance of the rubber cylinder is the best.The pressure and flow characteristics of the micro-hydraulic system in the hydraulic seal are analyzed,and the influences of the internal flow resistance,the working speed,the closed volume of the sliding sleeve cylinder,the oil gas content and other factors on the micro-hydraulic system are studied.After the simulation analysis,the downhole hydraulic system is optimized,adding an inlet booster structure to the system,analyzing the influence of adding the booster structure on the overall hydraulic system,and analyzing the moving speed,pressure and suction flow of the sliding cylinder liner.Finally,it is concluded that adding the inlet booster structure can effectively improve the dynamic response performance of the micro-hydraulic system.The combined seal of moving parts in hydraulic packer is studied.The movement of sliding sleeve cylinder can be simplified as piston movement.The combined seal structure composed of O-ring,cylinder block and slip ring groove is analyzed.Orthogonal test method is used to design the parameters of the sealing parts,and the sealing structure is simulated under different parameter combinations.The maximum contact stress value is used as reference.The results show that when the compression rate of O-ring is 30%,the hardness of O-ring is 90 HA,the number of grooves of slip ring is 1,and the thickness of slip ring is 1mm,the contact stress is the maximum and the sealing effect is the best.Finally,the leakage amount of the combined sealing process is analyzed,and the factors affecting the leakage amount such as pressure and temperature are analyzed,and the corresponding leakage calculation formula is derived.