Analytical solution to stress cage problem with particular application to wellbore

  • Liu Haoge

    Student thesis: Master's Thesis

    Abstract

    Stress cage is a concept of wellbore strengthening which has achieved great success in wellbore stability enhancement since 2004. But till now, there is no available analytical solution of stress state to its model. The availability of analytical solution of stress state to the stress cage model is not only meaningful to the perfection of stress cage concept, but also of great progress in wellbore stress analysis. Therefore, based on the linear elasticity assumption, this study tried to solve out the analytical solution of stress state to the stress cage model by Muskhelishvili (1953) method. However, the multi value of the conformal transformation equation for the stress cage model brought a lot of troubles, and the singularities of the Cauchy integral completely blocked this study from getting the analytical results. Then analysis of these two mathematical issues was done and the future work ahead was pointed out. Even though this study failed in getting the analytical solution of stress state to the stress cage model, but it found the analytical solution of stress state that can be used for the vertical wellbore suffered from collapse and washout which tends to be elliptical shape rather than a circular shape. Comparison of the results to the FEA was made which revealed the advantages of the analytical solution. And sensitive analysis found the effect of the ellipticity and formation anisotropy which can be quantified by the analytical solution.
    Date of Award2016
    Original languageAmerican English
    SupervisorMD Rahman (Supervisor)

    Keywords

    • Applied sciences
    • Stress analysis
    • Stress cage
    • Wellbore
    • Petroleum engineering
    • 0765:Petroleum engineering

    Cite this

    '