The Study On Key Problems For Dual String Packer Used In Heavy Oil Thermal Recovery

With the development of petroleum industry, the proportion of light crude oil is decreasing and the heavy oil is increasing gradually, so the in-situ need to develop new technology for heavy oil extract. Now they mainly use thermal recovery method as the viscosity of heavy oil can be decreased greatly under high temperature. During heavy oil thermal recovery, the cyclic steam stimulation technology is common used. The main mechanism is that injected the high temperature and high pressure steam into oil reservoir, gas put the heat to oil field, then the heavy oil viscosity decrease which is helpful for oil extract. Due to the cyclic steam stimulation technology need to transfer the heat energy into heavy oil as much as possible, so it need to use packer to seal the reservoir during exploitation. Thermal packer is a main tool for heavy oil thermal recovery, but there is less research on it in domestic and overseas.The packer rubber of new dual packer for heavy oil thermal recovery studing in this paper. The main contents are as follows:(1) Research on the structure differences and advantages/disadvantages between the thermal packer and normal packer. Select adaptive dual packer for heavy oil thermal recovery.(2) According to the working condition of heavy oil thermal recovery and the mechanical analysis of dual packer structure, select the packer rubber for mechanical analysis, the finite element modal builded based on relevant requirements and structure of critical position.(3) Using finite element method (FEM) analysis packer rubber, and get the analysis result about displacment, Von1 stress and contact stress. Based on the results of the analysis of packer rubber, combined with the material mechanical properties and the related theory, I forward a feasible decision condition packer, for subsequent about high temperature packer rubber tube assembly analysis contrast standard;(4) Packer rubber have different physical property under different temperature. Combine hot-set coupling mathematical model, simulated the packer rubber displacement,Von tress and contact stress under 300℃.compraison the different between the two temperature,get the result about the rubber can be used in heavy oil thermal recovery.(5) Through comparing the finite element analysis under different temperature, high temperature packer rubber deformation quantity is big, good for deformation of the rubber, the packer rubber internal equivalent stress decreases, the possibility of damage reduction, contact stress decreases after sealing performance of rubber tube is relatively lower but also can complete the packer.