Mechanical Analysis and Application of Multi-packer Tubing String in Layered Water Injection in Dagang Oilfield

Abstract

In Zaoyuan Oilfield and Wangguantun Oilfield of Dagang Oilfield Company, the wells feature large depth, high temperature, high water injection pressure, serious corrosion and scaling and complex wellbore conditions. The existing mechanical analysis software for tubing string in layered water injection is only capable of analyzing the axial force and axial deformation and checking the safety of strength under the lowering and lifting working conditions. Therefore, a mechanical analysis method for the multi-packer tubing string has been derived by comprehensively considering the constraint and impact of anchor tools and packers on tubing string deformation, the well deviation and orientation, the statical indeterminacy of the multi-packer tubing string as well as the impact of injected water temperature and expansion effect by injection pressure. The method is capable of analysis on the axial force, deformation and stress strength of each string segment of the layered water injection tubing string with two or more packers, and helps improve the accuracy of mechanical analysis of tubing string under different well conditions and working conditions. Case analysis shows that the analysis results can be used to guide the design of tubing string for layered water injection as well as to guide the research and development of auxiliary downhole tools such as layered water injection packers and anchor tools.