Study on sealing integrity of cement sheath in ultra deep well reservoir reconstruction

This article mainly studies the influence of high temperature, high pressure, and ultra-deep well reservoir renovation construction on wellbore barriers, and explores the impact of reservoir renovation on cement sheath under high temperature and high-pressure conditions. Combining the coupling effect of casing, cement, and formation rock, a three-dimensional numerical model is established to analyze the stress changes and distribution of the cement sheath during the volume fracturing process. By establishing a numerical model for the analysis of the integrity of the wellbore during the fracturing process of the ultra-deep well vertical section, the stress changes and distribution of the cement sheath during the fracturing process are analyzed. A numerical calculation model for crack propagation during perforation and cement sheath reservoir renovation is constructed, and the model results are verified through laboratory experiments and computed tomography scans. The shear failure of the cement sheath interface under different conditions such as different casing pressure, cement sheath thickness, elastic modulus, and Poisson's ratio is analyzed during the fracturing process. The research results can provide technical support for the integrity of the wellbore and the design of the well structure in similar ultra-deep well development processes.