热采井封隔器胶筒非线性大变形分析∗

摘要

井底复杂环境下封隔器胶筒的密封性能是影响热采井生产安全的关键因素之一。采用Yeoh本构模型表征胶筒超弹性与非线性特点，数值仿真封隔器坐封过程，分析胶筒非线性大变形，获得胶筒压缩距与接触应力变化规律。基于正交试验设计方法，系统研究了坐封载荷、井底温度、胶筒长度、胶筒厚度、胶筒与套管摩擦因数等对胶筒力学响应的影响。研究结果表明：封隔器坐封载荷与胶筒厚度是影响胶筒压缩距和接触应力的主控因素；随着坐封载荷增加，封隔器压缩距与接触应力非线性增大；胶筒厚度的增加能明显降低压缩距，提高接触应力。研究结果可为热采井封隔器型号优选提供依据。%The sealing performance of the packer rubber in complex downhole conditions is one of the key points affecting the production safety of thermal production wells. Yeoh constitutive model has been used to charac⁃ter the hyper⁃elasticity and non⁃linear characteristics of the packer rubber. Numerical simulation has been conducted to simulate the packer setting processand analyze the non⁃linear large deformation. The varying pattern of compres⁃sion space and contact stress has been attained. Based on the orthogonal method, the effect of various factors like⁃setting load, downhole temperature, rubber length, rubber thickness, rubber⁃casing friction coefficient on the me⁃chanical response of the packer rubber has been studied systematically. The results show that setting load and rub⁃ber thickness are the main controlling factors affecting compression space and contact stress of the packer rubber. The compression space and contact stress increase nonlinearly with the increase of setting load. The increase of rub⁃ber thickness would significantly decrease the compression space and increase contact stress. The study results could provide bases for packer selection for thermal recovery wells.